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Chapter 4 · Principles of Inheritance 159 and Variation

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S type: 43 Q ⤓ Export ZIP
#1 SUB 2M

Question

Describe the meaning of inheritance and variation.

Answer

Inheritance : The phenomenon of parental traits being passed on to offspring is called inheritance.
The continuous transmission of traits from one generation to the next is carried out by genes.
(2) Variation : Variation means that offspring differ from their parents.
Differences that occur among individuals of the same species are called variation.
Through the ability to reproduce, every organism produces new generations of offspring that resemble their parents.
Inheritance and variation in offspring are the result of sexual reproduction.
#2 SUB 3M

Question

Why is Gregor Mendel known as Father of genetics?

Answer

The contribution of Mendel to genetics is called Mendelism.
Gregor Mendel conducted hybridisation experiments on garden peas during 1856–1863 for several contrasting traits such as seed colour, pod colour, flower portion, and other characteristics, and collected systematic data.
He postulated the laws of inheritance, which are also called Mendel’s laws.
These laws laid the foundation of heredity.
Hence, G. J. Mendel is called the father of genetics.
#3 SUB 🖼 1

Question

Mention the advantages of selecting pea plant for experiment by Mendel.

Answer

The advantages of selecting pea plants for experiments are as follows:
The cultivation of pea plants is easy.
The plant shows clear contrasting traits.
The life span is short, about 2 to 4 months.
The bisexual flowers of pea plants normally undergo self-pollination, but cross-fertilisation can also be carried out easily.
Artificial hybridisation is highly successful.
The hybrids of pea plants are fertile.
A large number of offsprings are produced.

#4 SUB 4M 🖼 2

Question

Explain the Punnett square used to understand a typical monohybrid cross conducted by Mendel between true breeding tall plant and true line dwarf plant.
OR
Explain one gene inheritance by Punnett square.

Answer

Mendel selected the pea plant (Pisum sativum), in which the selected contrasting traits were tall and dwarf.
The monohybrid cross between the parental plants (tall and dwarf) resulted in hybrids in the F1 generation.
All the offspring in the F1 generation were tall.
When the F1 generation hybrids were crossed among themselves, the traits segregated in the F2 generation to give three tall and one dwarf plants (phenotypic ratio 3 : 1) and a genotypic ratio of 1 : 2 : 1.
The genotypic and phenotypic ratios of the offspring can be represented using a Punnett square.
Monohybrid Cross
Monohybrid cross
#5 SUB 🖼 1 ▦ 1

Question

Differentiate between: homozygous and heterozygous.

Answer

Homozygous

Heterozygous

1.

A zygote having identical genes / factors (alleles) is called homozygous.

A zygote having dissimilar genes / factors (alleles) is called heterozygous.

2.

It may possess either dominant alleles or recessive alleles.

Example: TT or tt — such a zygote is called pure (true).

It possesses one dominant and one recessive allele.

Example: Tt — such a zygote is called a hybrid.
#6 SUB 🖼 1 ▦ 1

Question

Differentiate between: dominant gene and recessive gene.

Answer

Dominant gene

Recessive gene

1.

A gene that is expressed in the presence or absence of its alternative gene is called a dominant gene.

A gene that is expressed only in the absence of its alternative gene is called a recessive gene.

2.

It dominates phenotypically and is expressed in the F1 generation.

It remains phenotypically suppressed in the F1 generation.

3.

It is represented by a capital letter.

Example: T for tall.

It is represented by a small letter.

Example: t for dwarf.
#7 SUB 🖼 6

Question

Using a Punnett Square, workout the distribution of phenotypic features in the first filial generation after a cross between a homozygous female and a heterozygous male for a single locus.

Answer

F1 generation: Punnett Square

Female

Gametes

A

a

a

Aa

aa

a

Aa

aa

Phenotype = 1 : 1 (Heterozygous 50%, Homozygous 50%)

#8 SUB 🖼 1

Question

A diploid organism is heterozygous for 4 loci; how many types of gametes can be produced?

Answer

Here, number of heterozygous pair n = 4
Types of gametes = 2n; where n = 4

= 24

= 16

16 types of gametes will be formed.
#9 SUB 3M 🖼 1

Question

Explain the Law of Dominance using a monohybrid cross.
OR
Describe the laws concluded from monohybrid cross.

Answer

The study of the inheritance of one trait with contrast characteristics is called monohybrid cross.
Law of Dominance (Mendel’s First Law):

(i) Characters are controlled by discrete units called factors.

(ii) Factors occur in pairs.

(iii) In a dissimilar pair of factors one member of the pair dominates (dominant) the other (recessive).

The law of dominance is used to explain the expression of only one of the parental characters in a monohybrid cross in the F1 and the expression of both in the F2. It also explains the proportion of 3:1 obtained at the F2.
Law of Segregation (Mendel’s Second Law):

(i) This law is based on the fact that the alleles do not show any blending and that both the characters are recovered as such in the F2 generation though one of these is not seen at the F1 stage.

(ii) The phenotypic ratio is 3 tall and 1 dwarf and genotypic ratio is 1 : 2 : 1.

(iii) Though the parents contain two alleles during gamete formation, the factors or alleles of a pair segregate from each other such that a gamete receives only one of the two factors.

Of course, a homozygous parent produces all gametes that are similar while a heterozygous one produces two kinds of gametes each having one allele with equal proportion.
#10 SUB 2M 🖼 1

Question

What is test cross? Give Punnett square presentation for the test cross for the colour of flower in the pea plant.
OR
Define and design a test-cross.
[NCERT Exercise Q.5]

Answer

To determine the genotype whether it is homozygous or heterozygous, test cross is conducted by crossing the unknown (hybrid) genotype and a homozygous recessive.
The genotype of dominant allele can be determined.
Example, Selected trait- flower colour.
Phenotype- violet flower (WW) and white (ww).
The F1 generation is a result of hybridisation, it contains violet flowers which can be homozygous (WW) or heterozygous (Ww).
For the test cross, F1 violet flower is crossed with the white flower which has two possible results:

(i) If the F1 generation is homozygous violet (WW), then all the offsprings will have violet flower.

(ii) If the F1 generation is heterozygous violet (Ww), then 50% flowers are white where as 50% flowers are violet, which means the ratio is 1 : 1.

.
#11 SUB 3M

Question

Explain the concept of dominance with suitable example.

Answer

Every gene, contains the information to express a particular trait.
In a diploid organism, there are two copies of each gene, i.e., a pair of alleles.
These two alleles are not always identical, as in a heterozygote.
One of them may be different due to some changes that it has undergone.

Let’s take an example :

A gene that contains the information for producing an enzyme.
Now, there are two copies of this gene, the two allelic forms.
Let us assume (as is more common) that the normal allele produces the normal enzyme that is needed for the transformation of a substrate S.
Theoretically, the modified allele could be responsible for production of –

(i) the normal/less efficient enzyme, or

(ii) a non-functional enzyme, or

(iii) no enzyme at all

In the first case, the modified allele is equivalent to the unmodified allele, i.e., it will produce the same phenotype / trait, i.e., result in the transformation of substrate S.
Such equivalent allele pairs are very common. But, if the allele produces a non-functional enzyme or no enzyme, the phenotype may be affected.
The phenotype / trait will only be dependent on the functioning of the unmodified allele.
The unmodified (functioning) allele, which represents the original phenotype is the dominant allele and the modified allele is generally the recessive allele.
Hence, in the example above the recessive trait is seen due to non-functional enzyme or because no enzyme is produced.
#12 SUB 3M PYQ 🖼 1

Question

Explain incomplete dominance in dog flower.
[NCERT Exercise Q.13(b)]
OR
Explain with suitable example the monohybrid cross in which the phenotypic and genotypic ratio of F2 generation is equal.
(MARCH 2023)

Answer

The inheritance of flower colour in the dog flower (snapdragon or Antirrhinum sp.) is a good example to understand incomplete dominance.
In a cross between true-breeding red-flowered (RR) and true-breeding white-flowered plants (rr), the F1 (Rr) was Pink.
When the F1 was self-pollinated, the F2
resulted in the following ratio: 1 (RR) Red: 2
(Rr) Pink: 1 (rr) White. Here, the genotype ratios were exactly as we would expect in any Mendelian monohybrid cross, but the phenotype ratios had changed from the 3:1 dominant : recessive ratio to 1 : 2 : 1.
Conclusion was that R was not completely dominant over r and this made it possible to distinguish Rr as pink from RR (red) and rr (white).
#13 SUB 4M

Question

Explain the basis of inheritance of the blood group in human population.
OR
Explain multiple allelism.
[NCERT Exercise Q.13(a)](MARCH 2020)
OR
Explain regulation of ABO blood group
OR
Explain Co-dominance regarding ABO blood group in humans.(JULY 2022)

Answer

When three or more then three alleles are responsible for any trait is called multiple allelism.
Co-dominance is a phenomenon in which both the parental trait is expressed in the F1 generation.
A good example is different types of red blood cells that determine ABO blood grouping in human beings. ABO blood groups are controlled by the gene I.
The plasma membrane of the red blood cells has sugar polymers that protrude from its surface and the kind of sugar is controlled by the gene.
The gene (I) has three alleles IA, IB and i.
The alleles IA and IB produce a slightly different form of the sugar while allele i does not produce any sugar.
Because, humans are diploid organisms, each person possesses any two of the three I gene alleles.
IA and IB are completely dominant over i, in other words when IA and i are present, only IA expresses (because i does not produce any sugar), and when IB and i are present, IB expresses.
But when IA and IB are present together they both express their own types of sugars: this is because of co-dominance.
Hence red blood cells have both A and B types of sugars.
Since, there are three different alleles, there are six different combinations of these three alleles that are possible, and therefore, a total of six different genotypes of the human ABO blood types.

Allele from Parent 1

Allele

from Parent 2

Genotype

of

offspring

Blood (group) types of offspring

I A

I A

I A I A

A

I A

I B

I A I B

AB

I A

i

I A i

A

I B

I A

I A I B

AB

I B

I B

I B I B

B

I B

i

I B i

B

i

i

i i

O

Genotype: Given in table
Phenotype: blood group A, B, AB and O
There are more than two, i.e., three alleles, governing the same character. Since, in an individual only two alleles can be present, multiple alleles can be found only when population studies are made.
#14 SUB 3M

Question

A single gene product may produce more than one effect- explain this with starch synthesis in pea seeds.
OR
Explain pleiotropy in pea seeds.

Answer

Starch synthesis in pea seeds is controlled by one gene. It has two alleles (B and b). Starch is synthesised effectively by BB homozygotes and therefore, large starch grains are produced. In contrast, bb homozygotes have lesser efficiency in starch synthesis and produce smaller starch grains.
After maturation of the seeds, BB seeds are round and the bb seeds are wrinkled. Heterozygotes produce round seeds, and so B seems to be the dominant allele.
But, the starch grains produced are of intermediate size in Bb seeds.
So, if starch grain size is considered as the phenotype, then from this angle, the alleles show incomplete dominance.
Therefore, dominance is not an autonomous feature of a gene or the product that it has information for. It depends as much on the gene product and the production of a particular phenotype from this product as it does on the particular phenotype.
#15 SUB 4M 🖼 1

Question

Explain Mendel’s monohybrid cross in detail.
OR
explain one gene inheritance experiment done by Mendel.

Answer

The study of inheritance of only one trait is called monohybrid cross.
Mendel had selected two plants of Pisum sativum.
One is pure line tall and other is pure line dwarf plant and both are taken as parents.
Hybridisation experiment were carried out by Mendel where he crossed tall and dwarf pea plants to study the inheritance of one gene.
He collected the seeds produced as a result of this cross and grew them to generate plants of the first hybrid generation.
This generation is also called the first Filial progeny or the F1.
Mendel observed that all the F1 progeny plants were tall, like one of its parents; none were dwarf.
He made similar observations for the other pairs of traits – he found that the F1 always resembled either one of the parents, and that the trait of the other parent was not seen in them.
Mendel then self-pollinated the tall F1 plants and to his surprise found that in the second Filial F2 generation some of the offspring were dwarf ; the character that was not seen in the F1 generation was now expressed.
Similar results were obtained with the other traits that he studied: only one of the parental traits was expressed in the F1 generation while at the F2 stage both the traits were expressed in the proportion 3:1( 75% are tall and 25% dwarf).
The contrasting traits did not show any blending at either F1 or F2 stage.
Based on these observations, Mendel proposed that something was being stably passed down, unchanged, from parent to offspring through the gametes, over successive generations.
#16 SUB 3M

Question

A child has blood group O. If the father has blood group A and mother has blood group B, work out the genotypes of the parents and the possible genotypes of their offsprings.
[NCERT Exercise Q.12]

Answer

Child's blood group O, genotype = ii
Father's blood group A, genotype = IA IA or IA i
Mother's blood group B, genotype = IB IB or IB i
(i) If father's blood group is A with genotype IA IA and mother's blood is B with genotype IB IB then,
IA IA × IB IB

gamete

IA

IA

IB

IA IB

IA IB

IB

IA IB

IA IB
Possible blood group of child is AB.

(ii) If father's blood group is A with genotype IA IA and mother's blood is B with genotype IB i then,

IA IA × IB i

gamete

IA

IA

IB

IA IB

IA IB

i

IA i

IA i

Possible blood group of child is A or AB.

(iii) If father's blood group is A with genotype IA i and mother's blood is B with genotype IB IB then,

IA i × IB IB

gamete

IA

i

IB

IA IB

IB i

IB

IA IB

IB i

Possible blood group of child is B or AB.

(iv) If father's blood group is A with genotype IA i and mother's blood is B with genotype IB i then,

IA i × IB i

gamete

IA

i

IB

IA IB

IB i

i

IA i

ii

Possible blood group of child would be A, B, AB or O.
#17 SUB 2M

Question

Drosophila (fruit fly) is used in experimental verification of the chromosomal theory of inheritance by Thomas Hunt Morgan. Why?

Answer

Following are the reasons behind choosing Drosophila in the study of inheritance by T. H. Morgan:
(1) Drosophila melanogaster which were found very suitable for such studies. They could be grown on simple synthetic medium in the laboratory.
(2) They complete their life cycle in about two weeks.
(3) A single mating could produce a large number of progeny flies.
(4) Also, there was a clear differentiation of the sexes – the male and female flies are easily distinguishable. And it has many types of hereditary variations that can be seen with low power microscopes.
#18 SUB 2M

Question

Mendel published his work on inheritance of characters in 1865 but for several reasons, it remained unrecognised till 1900. Why?

Answer

Because of following reasons, Mendel’s work remained unrecognised:
(1) Communication was not easy (as it is now) in those days and his work could not be widely publicised.
(2) His concept of genes (or factors, in Mendel’s words) as stable and discrete units that controlled the expression of traits and, of the pair of alleles which did not ‘blend’ with each other, was not accepted by his contemporaries as an explanation for the apparently continuous variation seen in nature.
(3) Mendel’s approach of using mathematics to explain biological phenomena was totally new and unacceptable to many of the biologists of his time.
(4) Though Mendel’s work suggested that factors (genes) were discrete units, he could not provide any physical proof for the existence of factors or say what they were made of.
The role of nucleus and chromosome was not known in the reproduction.
#19 SUB 2M ▦ 1

Question

compare a chromosome and gene.

Answer

Chromosome

Gene

1

Segregate at the time of gamete formation such that only one of each pair is transmitted to a gamete.

Segregate at the time of gamete formation and only one of each pair is transmitted to a gamete.

2

Independent pairs segregate independently of each other.

One pair segregates independently from another pair.
#20 SUB 1M 🖼 1

Question

When a cross in made between tall plant with yellow seeds (TtYy) and tall plant with green seed (Ttyy), what proportions of phenotype in the offspring could be expected to be
(a) tall and green.
(b) dwarf and green.

Answer

Phenotype : Tall and yellow 3
Tall and green 3
Dwarf and yellow 1
Dwarf and green 1
(a) Tall plant and green seed - 3
(b) Dwarf plant and green seed - 1
#21 SUB 🖼 2

Question

Two heterozygous parents are crossed. If the two loci are linked, what would be the distribution of phenotypic features in F1 generation for a dihybrid cross?

Answer

Two or more genes located on the same chromosome shows linkage.
If genes are located on one chromosome and tightly linked, it can be inherited to offspring, these genes are called linked gane.

Only two types of gametes are formed because the genes are linked.
#22 SUB 2M 🖼 3

Question

Explain dihybrid cross in detail. OR
Explain the inheritance of two genes with chart.
OR
Explain dihybrid cross with chart for given characteristics.

Answer

The gametes RY and ry unite on fertilization to produce the F1 hybrid RrYy.
When Mendel self hybridised the F1 plants he found that 3/4th of F2 plants had yellow seeds and 1/4th had green.
The yellow and green colour segregated in a 3:1 ratio.
Round and wrinkled seed shape also segregated in a 3:1 ratio; just like in a monohybrid cross.
Gametogenesis in F1 generation:

The Punnett square can be effectively used to understand the independent segregation of the two pairs of genes during meiosis and the production of eggs and pollen in the F1 RrYy plant.

Consider the segregation of one pair of genes R and r. Fifty per cent of the gametes have the gene R and the other 50 per cent have r.
Now besides each gamete having either R or r, it should also have the allele Y or y.
The important thing to remember here is that segregation of 50 per cent R and 50 per cent r is independent from the segregation of 50 per cent Y and 50 per cent y.
Therefore, 50 per cent of the r bearing gametes
has Y and the other 50 per cent has y.
Similarly, 50 per cent of the R bearing gametes has Y and the other 50 per cent has y.
Thus, there are four genotypes of gametes (four types of pollen and four types of eggs).
The four types are RY, Ry, rY and ry each with a frequency of 25 per cent or 1/4th of the total gametes produced.

In dihybrid cross

genotype in F2

RRyy - 1 : Rryy - 2 : rryy - 1

RRyy - 2 : Rryy - 4 : rryy - 2

RRyy - 1 : Rryy - 2 : rryy - 1

Genotypic ratio: 1 : 2 : 1 : 2 : 4 : 1 : 2 : 1

#23 SUB 🖼 2

Question

Give difference between monohybrid and dihybrid cross.

Answer

#24 SUB 🖼 2

Question

Explain chromosomal theory of inheritance.

Answer

Walter Sutton and Theodore Boveri noted that the behaviour of chromosomes was parallel to the behaviour of genes and used chromosome movement to explain Mendel’s laws.
Chromosomes and genes both are in a pair.
The two alleles of a gene pair are located on homologous sites on homologous chromosomes.
Segregation at the time of gamete formation such that only one of each pair is transmitted to a gamete.

Sutton and Boveri argued that the pairing and separation of a pair of chromosomes would lead to the segregation of a pair of factors they carried. Sutton united the knowledge of chromosomal segregation with Mendelian principles and called it the chromosomal theory of inheritance.
Following this synthesis of ideas, experimental verification of the chromosomal theory of inheritance by Thomas Hunt Morgan and his colleagues, led to discovering the basis for the variation that sexual reproduction produced.
#25 SUB 🖼 3

Question

Explain dihybrid crosses carried out by Morgan in Drosophila to study genes that were sex- linked. OR
Briefly mention the contribution of T.H Morgan.
OR
Describe contribution of Morgan in genetics.
OR
Who had proposed the chromosomal theory of inheritance?

Answer

Morgan carried out several dihybrid crosses in Drosophila to study genes that were sex-linked. The crosses were similar to the dihybrid crosses carried out by Mendel in peas.
For example Morgan hybridised yellow-bodied, white-eyed females to brown-bodied, red-eyed males and intercrossed their F1 progeny.
He observed that the two genes did not segregate independently of each other and the F2 ratio deviated very significantly from the 9:3:3:1 ratio (expected when the two genes are independent).
Morgan and his group knew that the genes were located on the X-chromosome and saw quickly that when the two genes in a dihybrid cross were situated on the same chromosome, the proportion of parental gene combinations were much higher than the non-parental type.
Morgan attributed this due to the physical association or linkage of the two genes and coined the term linkage to describe this physical association of genes on a chromosome and the term recombination to describe the generation of non-parental gene combinations.
Morgan and his group also found that even when genes were grouped on the same chromosome, some genes were very tightly linked (showed very low recombination) while others were loosely linked (showed higher recombination).
For example, he found that the genes white and yellow were very tightly linked and showed only 1.3 per cent recombination while white and miniature wing showed 37.2 per cent recombination.
#26 SUB 3M 🖼 1

Question

Explain polygenic inheritance with example.
OR
Explain inheritance of human skin colour by polygenic inheritance.

Answer

Mendel’s studies mainly described those traits that have distinct alternate forms such as pea flower colour which are either purple or white.
But, if we look around we will find that there are many traits which are not so distinct in their occurrence and are spread across a gradient.
For example, in humans we don’t just have tall or short people as two distinct alternatives but a whole range of possible heights. Such traits are generally controlled by three or more genes and are thus, called as polygenic traits.
Besides, the involvement of multiple genes polygenic inheritance also takes into account the influence of environment.
In a polygenic trait the phenotype reflects the contribution of each allele, i.e., the effect of each allele is additive.
Human skin colour is another classic example for this.
The three genes A, B, C control skin colour in human with the dominant forms A, B and C responsible for dark skin colour and the recessive forms a, b and c for light skin colour.

(1) The genotype with all the dominant alleles (AABBCC) will have the darkest skin colour and that with all the recessive alleles (aabbcc) will have the lightest skin colour.

(2) As expected the genotype with three dominant alleles and three recessive alleles will have an intermediate skin colour.

In this manner, the number of each type of alleles in the genotype would determine the darkness or lightness of the skin in an individual.

#27 SUB 🖼 1

Question

Describe pleiotropism.
OR
What is pleiotropy? Explain with suitable example.

Answer

A single gene can exhibit multiple phenotypic expression.
Such a gene is called a pleiotropic gene. The underlying mechanism of pleiotropy in most cases is the effect of a gene on metabolic pathways which contribute towards different phenotypes.
An example of this is the disease phenylketonuria, which occurs in humans.
The disease is caused by mutation in the gene that codes for the enzyme phenyl alanine hydroxylase (single gene mutation).
This manifests itself through phenotypic expression characterised by mental retardation and a reduction in hair and skin pigmentation.
#28 SUB 2M

Question

Explain the basis of sex determination in insects.
OR
Explain the contribution of Henking in sex determination.

Answer

Henking (1891) could trace a specific nuclear structure throughout spermatogenesis in a few insects, and it was also observed by him that 50 per cent of the sperm received this structure after spermatogenesis, whereas the other 50 per cent sperm did not receive it.
Henking gave a name to this structure as the X body but he could not explain its significance.
Further investigations by other scientists led to the conclusion that the ‘X body’ of Henking was in fact a chromosome and that is why it was given the name X-chromosome.
It was also observed that in a large number of insects the mechanism of sex determination is of the XO type, i.e., all eggs bear an additional X-chromosome besides the other chromosomes (autosomes).
On the other hand, some of the sperms bear the X-chromosome whereas some do not.
Eggs fertilised by sperm having an X-chromosome become females and, those fertilised by sperms that do not have an X-chromosome become males.
Due to the involvement of the X-chromosome in the determination of sex, it was designated to be the sex chromosome, and the rest of the chromosomes were named as autosomes.
#29 SUB 2M 🖼 1

Question

Explain sex determination in birds.

Answer

In some other organisms, e.g., birds, a different mechanism of sex determination is observed.
In this case the total number of chromosome is same in both males and females. But two different types of gametes in terms of the sex chromosomes, are produced by females,
i.e., female heterogamety.
The two different sex chromosomes of a female bird has been designated to be the Z and W chromosomes.
In these organisms the females have one Z and one W chromosome, whereas males have a pair of Z-chromosomes besides the autosomes.

#30 SUB 2M 🖼 1

Question

Explain sex determination in insects.
OR
Explain XX-XO type of sex determination.

Answer

This type of sex determination is studied first time in squash bug (protonate).
In this type of sex determination, the number of chromosomes determine the sex of animal.
XO type of sex determination in which the males have only one X-chromosome besides the autosomes, whereas females have a pair of
X-chromosomes.
Following chart explains sex determination in bugs and grosshopper.

AA = Autosomal chromosome

XX, XO = Sex chromosome

#31 SUB 🖼 2

Question

Explain sex determination in Human.

Answer

The sex determining mechanism in case of humans is XY type. Out of 23 pairs of chromosomes present, 22 pairs are exactly same in both males and females; these are the autosomes. A pair of X-chromosomes are present in the female, whereas, the presence of an X and Y chromosome are determinant of the male characteristic.
During spermatogenesis among males, two types of gametes are produced.
50 per cent of the total sperm produced carry the X-chromosome and the rest 50 per cent has Y-chromosome besides the autosomes. Females, however, produce only one type of ovum with an X-chromosome.
There is an equal probability of fertilization of the ovum with the sperm carrying either X or Y chromosome. In case the ovum fertilises with a sperm carrying X-chromosome the zygote develops into a female (XX) and the fertilization of ovum with Y-chromosome carrying sperm results into a male offspring.
Thus, it is evident that it is the genetic makeup of the sperm that determines the sex of the child.
In each pregnancy there is always 50 per cent probability of either a male or a female child.
#32 SUB 4M 🖼 1

Question

Explain haplo- diploid sex determination with suitable example. OR
Explain sex determination in honey bee.
OR
Explain sex determination in honey bee with chart.(MARCH / APRIL 2022)

Answer

The sex determination in honey bee is based on the number of sets of chromosomes an individual receives.
An offspring formed from the union of a sperm and an egg develops as a female (queen or worker), and an unfertilised egg develops as a male (drone) by means of parthenogenesis.
This means that the males have half the number of chromosomes than that of a female. The females are diploid having 32 chromosomes and males are haploid, i.e., having 16 chromosomes.
This is called as haplodiploid sex-determination system and has special characteristic features such as the males produce sperms by mitosis.
#33 SUB 3M

Question

what is mutation? Explain in general.

Answer

Mutation is a phenomenon which results in alteration of DNA sequences and consequently results in changes in the genotype and the phenotype of an organism.
In addition to recombination, mutation is another phenomenon that leads to variation in DNA.
One DNA helix runs continuously from one end to the other in each chromatid, in a highly supercoiled form.
Therefore, loss (deletions) or gain (insertion/duplication) of a segment of DNA, result in alteration in chromosomes.
Since genes are known to be located on chromosomes, alteration in chromosomes results in abnormalities or aberrations. Chromosomal aberrations are commonly observed in cancer cells.
In addition to the above, mutation also arise due to change in a single base pair of DNA. This is known as point mutation.
A classical example of such a mutation is sickle cell anemia.
Deletions and insertions of base pairs of DNA, causes frame-shift mutations.
However, there are many chemical and physical factors that induce mutations.
These are referred to as mutagens. UV radiations can cause mutations in organisms – it is a mutagen.
#34 SUB 2M

Question

A male contains extra X- chromosome in the 23 pair of chromosome. Identify the disorder and describe its characteristics.
OR
Explain : Klinefelter's Syndrome

Answer

This genetic disorder is caused due to the presence of an additional copy of X-chromosome resulting into a karyotype of 47, XXY. An individual has Klinefelter’s Syndrome.
Characteristics:

(1) Such an individual has overall masculine development.

(2) Testes are under developed.

(3) Less hair on the skin.

(4) The feminine development (development of breast, i.e., Gynaecomastia) is also expressed.

(5) Voice is also female like.

(6) Such individuals are sterile.

#35 SUB 2M PYQ

Question

Describe: Turner’s syndrome (June 2024)
OR
Explain X - Chromosomal monosomy seen in female of human.

Answer

In Turner’s syndrome, these is monosomy of
X-chromosomes.
Here, chromosomes are found 45 instead of 46.
Characteristics :
  • Stunted growth, short, wrinkled neck females are infertile due to underdeveloped ovaries.
  • Absence or underdevelopment of secondary sexual characters.
#36 SUB 2M PYQ ▦ 1

Question

Differentiate between Down’s syndrome and Turner’s syndrome. (AUGUST 2020)

Answer

Down’s syndrome

Turner’s syndrome

1.

It is disorder related to autosomal chromosome.

It is disorder related to sex chromosome.

2.

In this abnormality is seen in the 21 chromosome.

In this abnormality is seen in sek chromosome.

3.

It shows trisomy of 21st chromosome.

It shows monosomy in 23rd chromosome.

4.

Can occur to both male and female.

It can only occur in female.
#37 SUB 2M PYQ

Question

Describe phenylketonuria (PKU).
(MARCH 2024, June 2025)

Answer

This inborn error of metabolism is also inherited as the autosomal recessive trait.
The affected individual lacks an enzyme phenyl alanine hydroxylase that converts the amino acid phenylalanine into tyrosine.
As a result of this phenylalanine is accumulated and converted into phenylpyruvic acid and other derivatives.
Accumulation of these in cerebrospinal fluid in the brain results in mental retardation.
These are also excreted through urine because of their poor absorption by kidney.
#38 SUB 3M PYQ

Question

Describe Mendelian abnormality: Thalassemia.
(June 2025)

Answer

This is an autosome-linked recessive blood disease transmitted from parents to the offspring when both the partners are unaffected carrier for the gene (or heterozygous).
The defect could be due to either mutation or deletion which ultimately results in reduced rate of synthesis of one of the globin chains (α and β chains) that make up haemoglobin.
This causes the formation of abnormal haemoglobin molecules resulting into anaemia which is characteristic of the disease.
Thalassemia can be classified according to which chain of the haemoglobin molecule is affected.

1. α Thalassemia:

  • In α Thalassemia, production of α globin chain is affected.
  • α Thalassemia is controlled by two closely linked genes HBA 1 and HBA 2 on chromosome 16 of each parent and it is observed due to mutation or deletion of one or more of the four genes. The more genes affected, the less alpha globin molecules produced.

2. β Thalassemia :

  • In β Thalassemia, production of β globin chain is affected. While β Thalassemia is controlled by a single gene HBB on chromosome 11 of each parent and occurs due to mutation of one or both the genes.
  • Thalassemia differs from sickle-cell anaemia in that the former is a quantitative problem of synthesising too few globin molecules.
#39 SUB 🖼 1

Question

what is pedigree analysis? Give symbols used for pedigree analysis and draw pedigree chart for myotonic dystrophy.
OR
What is pedigree analysis? Suggest how such an analysis can be useful.

Answer

An analysis of traits in a several generations of a family is called the pedigree analysis.
In the pedigree analysis, the inheritance of a particular trait is represented in the family tree over generations. In human genetics, pedigree study provides a strong tool, which is utilised to trace the inheritance of a specific trait, abnormality or disease.
Some of the important standard symbols used in the pedigree analysis have been shown as follows.
Each and every feature in any organism is controlled by one or the other gene located on the DNA present in the chromosome. DNA is the carrier of genetic information. It is hence transmitted from one generation to the other without any change or alteration. However, changes or alteration do take place occasionally.
Such an alteration or change in the genetic material is referred to as mutation. A number of disorders in human beings have been found to be associated with the inheritance of changed or altered genes or chromosomes.
The pedigree analysis of Autosomal dominant trait Myotonic dystrophy is as follows:
#40 SUB 2M PYQ

Question

what is Mendelian disorders (genetic disorders)? Explain genetic abnormalities seen in haemophilia and colour blindness with its characteristics. OR
Mention any two genetic disorders with their symptoms. OR
Explain genetic disorders caused due to
X- chromosom linked recessive gene.
(JULY 2022)
OR
What are Mendelian disorders? Explain any two disorders related to sex linked chromosomal recessive genes.

Answer

Mendelian disorders are mainly determined by alteration or mutation in the single gene. These disorders are transmitted to the offsprings on the same lines as we have studied in the principle of inheritance. The pattern of inheritance of such Mendelian disorders can be traced in a family by the pedigree analysis. It is important to mention that such Mendelian disorders may be dominant or recessive.
1. Colour Blindness : (JUNE 2024)
It is a sex-linked recessive disorder due to defect in either red or green cone cell of eye resulting in failure to differentiate discriminate between red and green colour. This defect is due to mutation in certain genes present in the X chromosome (Sex chromosome).
It occurs in about 8 per cent of males and only about 0.4 per cent of females. This is because the genes that lead to red-green colour blindness are on the X-chromosome.
Males have only one X-chromosome and females have two. The son of a woman who carries the gene has a 50 per cent chance of being colour blind.
The mother is not herself colour blind because the gene is recessive.
That means that its effect is suppressed by her matching dominant normal gene.
A daughter will not normally be colour blind, unless her mother is a carrier and her father is colour blind.
2. Haemophilia :
This sex linked recessive disease, which shows its transmission from unaffected carrier female to some of the male progeny. In this disease, a single protein that is a part of the cascade of proteins involved in the clotting of blood is affected.
Due to this, in an affected individual a simple cut will results in non-stop bleeding.
The heterozygous female (carrier) for haemophilia may transmit the disease to sons.
The possibility of a female becoming a haemophilic is extremely rare because mother of such a female has to be atleast carrier and the father should be haemophilic (unviable in the later stage of life).
The family pedigree of Queen Victoria shows a number of haemophilic descendants as she was a carrier of the disease.
#41 SUB 4M 🖼 3

Question

what is point mutation? Explain with suitable example.
OR
Explain: sickle cell anemia.

Answer

Mutation also arise due to change in a single base pair of DNA. This is known as point mutation.
A classical example of such a mutation is sickle cell anemia.

Sickle cell anemia :

This is an autosome linked recessive trait that can be transmitted from parents to the offspring when both the partners are carrier for the gene (or heterozygous). The disease is controlled by a single pair of allele, HbA and HbS. Out of the three possible genotypes only homozygous individuals for HbS (HbS HbS) show the diseased phenotype. Heterozygous (HbA HbS) individuals appear apparently unaffected but they are carrier of the disease as there is 50 per cent probability of transmission of the mutant gene to the progeny, thus exhibiting sickle-cell trait.
The defect is caused by the substitution of Glutamic acid (Glu) by Valine (Val) at the sixth position of the beta globin chain of the haemoglobin molecule. The substitution of amino acid in the globin protein results due to the single base substitution at the sixth codon of the beta globin gene from GAG to GUG.
The mutant haemoglobin molecule undergoes polymerisation under low oxygen tension causing the change in the shape of the RBC from biconcave disc to elongated sickle like structure.
#42 SUB 4M

Question

what are chromosomal abnormalities? Give any two aneuploidy that occurs in human chromosomes, with characteristics.
OR
Explain the disorder occurs due to trisomy of Chromosome-21.

Answer

The number of chromosomes are fixed in any species. The chromosomal disorders are caused due to absence or excess or abnormal arrangement of one or more chromosomes. Such a change occurs due to loss or gain of one chromosome in a group. There are two types of chromosomal abnormalities.
Euploidy and Aneuploidy
Aneuploidy : Loss or gain of one or more chromosomes in a pair of chromosomes is called aneuploidy.
  • Normally, a pair of homozygous chromosomes consists of two chromosomes. but in such cases there is only one or none at all or three or four chromosomes.

(a) Hypoploidy : Monosomy (2n – 1), nullisomy
(2n – 2).

(b) Hyperploidy : Trisomy (2n + 1), Tetrasomy
(2n + 2)

  • Somatic chromosomal aneuploidy is associated with the somatic chromosomes.
  • Sex chromosomal aneuploidy is associated with the sex chromosomes.

(i) Down’s syndrome :

  • The cause of this genetic disorder is the presence of an additional copy of the chromosome number 21 (trisomy of 21).
  • This disorder was first described by Langdon Down (1866).

(1) The affected individual is short statured with small round head, furrowed tongue, partially open mouth.

(2) Palm is broad with characteristic palm crease. Physical, psychomotor and mental development is retarded.

(ii) Klinefelter’s Syndrome :

  • This genetic disorder is also caused due to the presence of an additional copy of X-chromosome resulting into a karyotype of 47, XXY.

(1) Such an individual has overall masculine development, however, the feminine development (development of breast, i.e., Gynaecomastia) is also expressed. Testes are underdeveloped.

(2) Such individuals are sterile.

#43 SUB 🖼 1

Question

Who gave chromosomal theory of inheritance?

Answer

In 1903, Sutton and Boveri gave chromosomal theory of inheritance.
S type: 242 Q ⤓ Export ZIP
#44 MCQ 1M

Question

Conditions of a karyotype 2n + 1, 2n – 1 and 2n + 2, 2n – 2 are called _______ .

Options

  1. (A) Aneuploidy
  2. (B) Polyploidy
  3. (C) Allopolyploidy
  4. (D) Monosomy

Answer

(A) Aneuploidy

#45 MCQ 1M

Question

All genes located on the same chromosome _______ .

Options

  1. (A) Form different groups depending upon their relative distance.
  2. (B) Form one linkage group.
  3. (C) Will not form any linkage groups.
  4. (D) Form interactive groups that affect the phenotype.

Answer

(B) Form one linkage group.

#46 MCQ 1M

Question

Distance between the genes and percentage of recombination shows _______ .

Options

  1. (A) a direct relationship
  2. (B) an inverse relationship
  3. (C) a parallel relationship
  4. (D) no relationship

Answer

(A) a direct relationship

#47 MCQ 1M

Question

Which of the following will not result in variations among siblings?

Options

  1. (A) Independent assortment of genes
  2. (B) Crossing over
  3. (C) Linkage
  4. (D) Mutation

Answer

(C) Linkage

#48 MCQ 1M

Question

In sickle cell anaemia, glutamic acid is replaced by valine. Which one of the following triplets codes for valine?

Options

  1. (A) G G G
  2. (B) A A G
  3. (C) G A A
  4. (D) G U G

Answer

(D) G U G

#49 MCQ 1M

Question

If a genetic disease is transferred from a phenotypically normal but carrier female to only some of the male progeny, the disease
is _______ .

Options

  1. (A) Autosomal dominant
  2. (B) Autosomal recessive
  3. (C) Sex-linked dominant
  4. (D) Sex-linked recessive

Answer

(D) Sex-linked recessive

#50 MCQ 1M

Question

Person having genotype IA IB would show the blood group AB. This is because of _______.

Options

  1. (A) Pleiotropy
  2. (B) Co-dominance
  3. (C) Segregation
  4. (D) Incomplete dominance

Answer

(B) Co-dominance

#51 MCQ 1M

Question

ZZ / ZW type of sex determination is seen
in _______ .

Options

  1. (A) Platypus
  2. (B) Snails
  3. (C) Cockroach
  4. (D) Peacock

Answer

(D) Peacock

#52 MCQ 1M

Question

A cross between two tall plants resulted in offsprings having few dwarf plants. What would be the genotypes of both the parents?

Options

  1. (A) TT and Tt
  2. (B) Tt and Tt
  3. (C) TT and TT
  4. (D) Tt and tt

Answer

(B) Tt and Tt

#53 MCQ 1M

Question

In a dihybrid cross, if you get 9 : 3 : 3 : 1 ratio it denotes that _______ .

Options

  1. (A) The alleles of two genes are interacting with each other.
  2. (B) It is a multigenic inheritance.
  3. (C) It is a case of multiple allelism.
  4. (D) The alleles of two genes are segregating independently.

Answer

(D) The alleles of two genes are segregating independently.

#54 MCQ 1M

Question

Two genes 'A' and 'B' are linked. In a dihybrid cross involving these two genes, the F1 heterozygote is crossed with homozygous recessive parental type (aa bb). What would be the ratio of offspring in the next generation?

Options

  1. (A) 1 : 1 : 1 : 1
  2. (B) 9 : 3 : 3 : 1
  3. (C) 3 : 1
  4. (D) 1 : 1

Answer

(D) 1 : 1

#55 MCQ 1M

Question

Mother and father of a person with 'O' blood group have 'A' and 'B' blood group, respectively. What would be the genotype of both mother and father?

Options

  1. (A) Mother is homozygous for 'A' blood group and father is heterozygous for 'B'.
  2. (B) Mother is heterozygous for 'A' blood group and father is homozygous for 'B'.
  3. (C) Both mother and father are heterozygous for 'A' and 'B' blood group, respectively.
  4. (D) Both mother and father are homozygous for 'A' and 'B' blood group, respectively.

Answer

(C) Both mother and father are heterozygous for 'A' and 'B' blood group, respectively.

#56 MCQ 1M

Question

Occasionally, a single gene may express more than one effect. The phenomenon is called _______.

Options

  1. (A) multiple allelism
  2. (B) mosaicism
  3. (C) pleiotropy
  4. (D) polygeny

Answer

(C) pleiotropy

#57 MCQ 1M

Question

The inheritance pattern of a gene over generations among humans is studied by the pedigree analysis. Character studied in the pedigree analysis is equivalent to _______.

Options

  1. (A) Quantitative trait
  2. (B) Mendelian trait
  3. (C) Polygenic trait
  4. (D) Maternal trait

Answer

(B) Mendelian trait

#58 MCQ 1M

Question

It is said that Mendel proposed that the factor controlling any character is discrete and independent. His proposition was based on
the _______ .

Options

  1. (A) results of F3 generation of a cross.
  2. (B) observations that the offspring of a cross made between the plants having two contrasting characters shows only one character without any blending.
  3. (C) self pollination of F1 offsprings.
  4. (D) cross pollination of F1 generation with recessive parent.

Answer

(B) observations that the offspring of a cross made between the plants having two contrasting characters shows only one character without any blending.

#59 MCQ 1M

Question

In the F2 generation of a Mendelian dihybrid cross the number of phenotypes and genotypes are _______ .

Options

  1. (A) phenotypes - 4; genotypes - 16
  2. (B) phenotypes - 9; genotypes - 4
  3. (C) phenotypes - 4; genotypes - 8
  4. (D) phenotypes - 4; genotypes - 9

Answer

(D) phenotypes - 4; genotypes - 9

#60 MCQ 1M

Question

In a certain taxon of insects some have 17 chromosomes and the others have 18 chromosomes. The 17 and 18 chromosome bearing organisms are _______ .

Options

  1. (A) males and females, respectively
  2. (B) females and males, respectively
  3. (C) all males
  4. (D) all females

Answer

(A) males and females, respectively

#61 MCQ 1M

Question

Mendel’s Law of independent assortment holds good for genes situated on the _______.

Options

  1. (A) non-homologous chromosomes
  2. (B) homologous chromosomes
  3. (C) extra nuclear genetic element
  4. (D) same chromosome

Answer

(B) homologous chromosomes

#62 MCQ 1M

Question

Who believed that 'factors' are responsible for hereditary information?

Options

  1. (A) Mendel
  2. (B) Johannsen
  3. (C) Bateson and Punnet
  4. (D) Morgan

Answer

(A) Mendel

#63 MCQ 1M

Question

Mendel's factors, the carriers of heredity information are known as 'genes' a term coined by :

Options

  1. (A) Bateson
  2. (B) Johannsen
  3. (C) Morgan
  4. (D) Tschermak

Answer

(B) Johannsen

#64 MCQ 1M

Question

Mendelism is related with .

Options

  1. (A) Heredity in living beings.
  2. (B) Meiosis during sexual reproduction
  3. (C) Mutation in living organisms
  4. (D) Crossing over and linkage

Answer

(A) Heredity in living beings.

#65 MCQ 1M

Question

The first great "geneticist" was ________.

Options

  1. (A) Engler
  2. (B) Mendel
  3. (C) Bateson
  4. (D) Boveri

Answer

(B) Mendel

#66 MCQ 1M

Question

Through artificial selection and domestication from ancestral wild cows, we have well-known Indian breeds, e.g., Sahiwal cows which belongs to which state?

Options

  1. (A) Punjab
  2. (B) Gujarat
  3. (C) Rajasthan
  4. (D) Uttar Pradesh

Answer

(A) Punjab

#67 MCQ 1M

Question

Mating between two individual differing in genotypes to produce genetic variation is called

Options

  1. (A) Domestication
  2. (B) Introduction
  3. (C) Hybridisation
  4. (D) Mutation

Answer

(C) Hybridisation

#68 MCQ 1M

Question

Mendel did his work on ________.

Options

  1. (A) Pisum sativum
  2. (B) Drosophila melanogaster
  3. (C) Mirabilis jalapa
  4. (D) Lathyrus odoratus

Answer

(A) Pisum sativum

#69 MCQ 1M

Question

In Mendel's monohybrid experiment, how many different characters are selected to carry out similar experiments?

Options

  1. (A) 2
  2. (B) 4
  3. (C) 7
  4. (D) 1

Answer

(D) 1

#70 MCQ 1M

Question

Which of the parental plants Mendel has selected for his experiments ?

Options

  1. (A) Heterozygous and pure
  2. (B) Homozygous and mixed
  3. (C) Homozygous and pure
  4. (D) Heterozygous and mixed

Answer

(C) Homozygous and pure

#71 MCQ 1M

Question

In a monohybrid cross of Mendel, the different phenotypes available in F1 generation
are ________.

Options

  1. (A) pure, tall
  2. (B) mixed, dwarf
  3. (C) heterozygous, tall
  4. (D) heterozygous, dwarf

Answer

(C) heterozygous, tall

#72 MCQ 1M

Question

How many different types of plants are formed in F2 progeny obtained from self-pollination of a F1?

Options

  1. (A) 1
  2. (B) 2
  3. (C) 4
  4. (D) 16

Answer

(B) 2

#73 MCQ 1M

Question

First generation after a cross is

Options

  1. (A) First filial generation
  2. (B) F1 generation
  3. (C) Second filial generation
  4. (D) Both A and B

Answer

(D) Both A and B

#74 MCQ 1M

Question

Mendel is famous for his work on

Options

  1. (A) Pisum
  2. (B) Drosophila
  3. (C) Neurospora
  4. (D) Oenothera

Answer

(A) Pisum

#75 MCQ 1M

Question

Mendel was lucky because.

Options

  1. (A) Pisum sativum is a long lived plant
  2. (B) Pisum sativum shows more contrasting character.
  3. (C) The genes for different characters are located on different chromosomes in Pisum sativum
  4. (D) The Pisum sativum is short-lived plant.

Answer

(C) The genes for different characters are located on different chromosomes in Pisum sativum

#76 MCQ 1M

Question

How many true breeding pea plant varieties did Mendel select as pairs, which were similar except in one character with contrasting traits ?

Options

  1. (A) 8
  2. (B) 4
  3. (C) 2
  4. (D) 14

Answer

(D) 14

#77 MCQ 1M

Question

Number of linkage group in Pisum sativum is

Options

  1. (A) 2
  2. (B) 5
  3. (C) 7
  4. (D) 9

Answer

(C) 7

#78 MCQ 1M

Question

Mendel chose the pea plant to study genetics because of many qualities. One of them which he did not consider was _______ .

Options

  1. (A) Plant height
  2. (B) Plant colour
  3. (C) Pod shape
  4. (D) Pod colour

Answer

(B) Plant colour

#79 MCQ 1M

Question

Mendel's law of heredity can be explained with the help of _______ .

Options

  1. (A) Mitosis
  2. (B) Meiosis
  3. (C) Both mitosis and meiosis
  4. (D) None of the above

Answer

(B) Meiosis

#80 MCQ 1M

Question

When an allele fails to explain itself in the presence of other allele, the former is said to be _______ .

Options

  1. (A) Recessive
  2. (B) Dominant
  3. (C) Codominant
  4. (D) Complementary

Answer

(A) Recessive

#81 MCQ 1M

Question

Allele is the _______ .

Options

  1. (A) Alternate trait of gene pair
  2. (B) Total number of genes for a trait
  3. (C) Total number of chromosomes
  4. (D) Total number of chromosomes of a haploid set

Answer

(A) Alternate trait of gene pair

#82 MCQ 1M

Question

Genotype-Phenotype concept was first produced by _______ .

Options

  1. (A) Bateson
  2. (B) Johannsen
  3. (C) Sutton & Boveri
  4. (D) Punnett

Answer

(B) Johannsen

#83 MCQ 1M

Question

Mendel chose pea plants because _______ .

Options

  1. (A) They were cheap.
  2. (B) They were having seven pairs of contrasting characters.
  3. (C) They were easily available.
  4. (D) They were of great economic importance.

Answer

(B) They were having seven pairs of contrasting characters.

#84 MCQ 1M

Question

Two pea plants were subjected to cross pollination of the 183 plants produced in the next generation. 94 plants were found to be tall and 89 plants were found to be dwarf. The genotypes of the two parental plants were likely to be :

Options

  1. (A) TT and tt
  2. (B) Tt and Tt
  3. (C) Tt and tt
  4. (D) TT and TT

Answer

(C) Tt and tt

#85 MCQ 1M

Question

In a monohybrid cross between two heterozygous individuals, the number of pure homozygous individuals obtained in F1 generation is :

Options

  1. (A) 2
  2. (B) 4
  3. (C) 6
  4. (D) 8

Answer

(A) 2

#86 MCQ 1M

Question

What will be the genotypes of parental generation, if all progeny obtained in F1 were recessive and dwarf:

Options

  1. (A) TT and tt
  2. (B) tt and tt
  3. (C) tt and Tt
  4. (D) Tt and Tt

Answer

(B) tt and tt

#87 MCQ 1M

Question

What is a dominant gene?

Options

  1. (A) Both the genes expresses their expression together.
  2. (B) The allele which expresses it character.
  3. (C) The allele which remains unexpressed.
  4. (D) Multiple effect of a single gene.

Answer

(B) The allele which expresses it character.

#88 MCQ 1M

Question

The allele which is not expressed is called :

Options

  1. (A) Recessive gene
  2. (B) Dominant gene
  3. (C) Homozygous gene
  4. (D) Co-dominant gene

Answer

(A) Recessive gene

#89 MCQ 1M

Question

Both the genes of a character are identical
is _______ .

Options

  1. (A) Homozygous
  2. (B) Heterozygous
  3. (C) Dominant
  4. (D) Co-dominant

Answer

(A) Homozygous

#90 MCQ 1M

Question

Which option is true for test - cross?

Options

  1. (A) Tt × Tt
  2. (B) TT × TT
  3. (C) Tt × tt
  4. (D) tt × tt

Answer

(C) Tt × tt

#91 MCQ 1M

Question

Both the genes of character are unlike in: _______

Options

  1. (A) Homozygous
  2. (B) Incomplete dominant
  3. (C) Heterozygous
  4. (D) Co-dominant

Answer

(C) Heterozygous

#92 MCQ 1M

Question

A cross, arranged for deciding whether an organism is homozygous or heterozygous is :

Options

  1. (A) Epistasis
  2. (B) Test-cross
  3. (C) Back cross
  4. (D) Monohybrid-cross

Answer

(B) Test-cross

#93 MCQ 1M 🖼 8

Question

The results obtained from self- fertilization amongst F1 individuals in Mendel's Monohybrid cross is :

Options

  1. (A) Dominant and Recessive
  2. (C) Dominant and Recessive
  3. (D) Dominant and Recessive

Answer

(A) Dominant and Recessive

#94 MCQ 1M

Question

The phenotype and genotype ratios of test-cross is:

Options

  1. (A) 3 : 1 and 1 : 1
  2. (B) 1 : 1 and 3 : 1
  3. (C) 1 : 1 and 1 : 1
  4. (D) 9 : 3 and 3 : 1

Answer

(C) 1 : 1 and 1 : 1

#95 MCQ 1M

Question

If homozygous recessive parent crosses with homozygous dominant parent, then what will be the result ?

Options

  1. (A) 100% heterozygous dominant progeny
  2. (B) 50% dominant and 50% recessive progeny
  3. (C) 70% dominant and 25% recessive progeny
  4. (D) 70% dominant and 30% recessive progeny

Answer

(A) 100% heterozygous dominant progeny

#96 MCQ 1M

Question

Heterozygous tall plant (Tt) is crossed with homozygous dwarf (tt) plant. Then what will be the result ?

Options

  1. (A) All progeny will be (Tt) tall
  2. (B) 50% Tt and 50% tt progeny
  3. (C) 70% TT and 30% tt progeny
  4. (D) 75% Tt and 25% tt progeny

Answer

(B) 50% Tt and 50% tt progeny

#97 MCQ 1M

Question

Incomplete dominance can be studied through experiments on :

Options

  1. (A) Sweet pea
  2. (B) Dog flower
  3. (C) Drosophila
  4. (D) E.Coli

Answer

(B) Dog flower

#98 MCQ 1M

Question

What is phenotypic and genotypic ratio of incomplete dominance in F2 ?

Options

  1. (A) 3 : 1 and 1 : 2 : 1
  2. (B) 1 : 2 : 1 and 1 : 2 : 1
  3. (C) 3 : 1 and 3 : 1
  4. (D) 1 : 2 : 2 and 1 : 1

Answer

(B) 1 : 2 : 1 and 1 : 2 : 1

#99 MCQ 1M

Question

When homozygous red flowered and homozygous white flowered are crossed all offsprings in F1 generation are.

Options

  1. (A) Pink
  2. (B) White
  3. (C) Red
  4. (D) All of above

Answer

(A) Pink

#100 MCQ 1M

Question

In Mirabilis a plant with RW is crossed with RW then the expected percentage value of red, pink and white is. (R = Red, W = White)

Options

  1. (A) 25% 50%, 25%
  2. (B) 25%, 25%, 50%
  3. (C) 10%, 20% 70%
  4. (D) 50% 25%, 25%

Answer

(A) 25% 50%, 25%

#101 MCQ 1M

Question

In Mirabilis, a hybrid with pink (RW) flower is crossed with white flower (WW), then the expected phenotypic and genotypic ratio
is ________.

Options

  1. (A) Phenotype: Red White, Genotype : RR, WW
  2. (B) Phenotype : Pink, Pink, Genotype : RW RW
  3. (C) Phenotype: Pink, White, Genotype : RW, WW
  4. (D) Phenotype : White, White, Genotype : WW, WW

Answer

(C) Phenotype: Pink, White, Genotype : RW, WW

#102 MCQ 1M

Question

In which case dominant and recessive alleles lack their dominant and recessive
relationships?

Options

  1. (A) Incomplete dominance
  2. (B) Polygenic inheritance
  3. (C) Co-dominance
  4. (D) Dominance

Answer

(C) Co-dominance

#103 MCQ 1M

Question

A child's blood group is ‘O’ The parents' blood groups cannot be

Options

  1. (A) A and B
  2. (B) AB and O
  3. (C) A and A
  4. (D) B and O

Answer

(B) AB and O

#104 MCQ 1M

Question

A child of O-group has B-group father. The genotype of father will be

Options

  1. (A) IOIO
  2. (B) IBIB
  3. (C) IAIB
  4. (D) IBIO

Answer

(D) IBIO

#105 MCQ 1M

Question

A man of A-blood group marries a woman of AB blood group. Which type of progeny would indicate that man is heterozygous A?

Options

  1. (A) AB
  2. (B) A
  3. (C) O
  4. (D) B

Answer

(D) B

#106 MCQ 1M

Question

ABO blood groups are controlled by which gene?

Options

  1. (A) A
  2. (B) I
  3. (C) B
  4. (D) C

Answer

(B) I

#107 MCQ 1M

Question

Co-dominance refers to the condition
where F1 :

Options

  1. (A) resembles the dominant parent
  2. (B) is in-between the parents
  3. (C) resembled the recessive parents
  4. (D) resembles both the parents

Answer

(D) resembles both the parents

#108 MCQ 1M

Question

What does blending inheritance refer to?

Options

  1. (A) Mixed characters in an offspring
  2. (B) Dominant character
  3. (C) Recessive character
  4. (D) Dominant & recessive character

Answer

(A) Mixed characters in an offspring

#109 MCQ 1M

Question

ABO blood group system is due to

Options

  1. (A) multifactor inheritance
  2. (B) incomplete dominance
  3. (C) multiple allelism
  4. (D) epistasis.

Answer

(A) multifactor inheritance

#110 MCQ 1M

Question

Which gene produce antigen for blood group?

Options

  1. (A) I
  2. (B) i
  3. (C) A
  4. (D) B

Answer

(A) I

#111 MCQ 1M

Question

Inheritance of blood type in humans is the example of ________.

Options

  1. (A) multiple alleles
  2. (B) co-dominance
  3. (C) polygenic inheritance
  4. (D) incomplete dominance

Answer

(A) multiple alleles

#112 MCQ 1M

Question

Which gene shows co-dominance for producing antigen?

Options

  1. (A) IAIA or IAi
  2. (B) IBIB or IBi
  3. (C) IAIB
  4. (D) ii

Answer

(C) IAIB

#113 MCQ 1M

Question

Who described human blood groups?

Options

  1. (A) Morgan
  2. (B) Landsteiner
  3. (C) Devenport
  4. (D) Mended

Answer

(B) Landsteiner

#114 MCQ 1M

Question

Which condition decided blood group in human beings?

Options

  1. (A) Antigen types on RBCs
  2. (B) Antibody in blood plasma
  3. (C) Antigen types in blood plasma
  4. (D) A and B both

Answer

(D) A and B both

#115 MCQ 1M

Question

Which blood group has antibody 'a' as well as antibody 'b'?

Options

  1. (A) A
  2. (B) AB
  3. (C) B
  4. (D) O

Answer

(D) O

#116 MCQ 1M

Question

If the mother and father have 'O' blood group, then what will be probable blood group of the child?

Options

  1. (A) O
  2. (B) O, A
  3. (C) O, B
  4. (D) A, B

Answer

(A) O

#117 MCQ 1M

Question

If mother has O blood group and father has A blood group then what will be the probable blood group of the child?

Options

  1. (A) A, B, AB
  2. (B) O, A
  3. (C) B, O
  4. (D) AB, O

Answer

(B) O, A

#118 MCQ 1M

Question

If mother has O blood group and father has B blood group then what will be probable blood group of the child?

Options

  1. (A) A, B, O
  2. (B) A, O
  3. (C) O, B (D)AB AB

Answer

(C) O, B (D)AB AB

#119 MCQ 1M

Question

What will be the probable blood group of parents having children sequencely A and O blood group?

Options

  1. (A) A, A
  2. (B) A, B
  3. (C) B, AB
  4. (D) A, AB

Answer

(A) A, A

#120 MCQ 1M

Question

What will be the probable blood group of parents having children sequencely A, B, AB and O blood groups?

Options

  1. (A) A, B
  2. (B) A, AB
  3. (C) B B (D)AB,AB

Answer

(A) A, B

#121 MCQ 1M

Question

What will be the probable blood group of a couple having three children with blood group sequencely A, B and AB?

Options

  1. (A) A, B
  2. (B) B, B
  3. (C) A, AB
  4. (D) AB, O

Answer

(C) A, AB

#122 MCQ 1M

Question

A couple has two sons. Out of the two, one son has B blood group and another has O blood group, then what is the probable blood group of the couple?

Options

  1. (A) AB. O
  2. (B) B, B
  3. (C) AB, AB
  4. (D) A, B

Answer

(B) B, B

#123 MCQ 1M

Question

A woman with blood group O has a child with blood group O. She claims that a man with blood group 'A' is the father of her child. What would be the genotype of the father, if her claim is right?

Options

  1. (A) IOIO
  2. (B) IAIB
  3. (C) IAi
  4. (D) IAIA

Answer

(C) IAi

#124 MCQ 1M

Question

For a child having blood group B, if father has blood group A, what may be the blood group of mother?

Options

  1. (A) B or AB
  2. (B) O or A
  3. (C) A or B
  4. (D) AB or A

Answer

(A) B or AB

#125 MCQ 1M

Question

A person with unknown blood group under ABO system, has suffered much blood loss in an accident and needs immediate blood transfusion. His friend who has a valid certificate of his own blood type, offers for blood donation without delay. What would have been the type of blood group of the donor friend ?

Options

  1. (A) Type A
  2. (B) Type A
  3. (C) Type AB
  4. (D) Type O

Answer

(D) Type O

#126 MCQ 1M

Question

If a child has O type of blood group and father has B type, the genotype of the father will be :

Options

  1. (A) IOIO
  2. (B) IAIB
  3. (C) IOiB
  4. (D) IBIB

Answer

(C) IOiB

#127 MCQ 1M

Question

The genotypes of a husband and wife are IAIB and IAi. Among the blood types of their children, how many different genotypes and phenotypes are possible?

Options

  1. (A) 3 genotypes; 4 phenotypes
  2. (B) 4 genotypes. 3 phenotypes
  3. (C) 4 genotypes, 4 phenotypes
  4. (D) 3 genotypes, 3 phenotypes

Answer

(C) 4 genotypes, 4 phenotypes

#128 MCQ 1M

Question

Test cross is shown by _______ .

Options

  1. (A) Tt × Tt
  2. (B) Tt × TT
  3. (C) TT × TT
  4. (D) Tt × tt

Answer

(D) Tt × tt

#129 MCQ 1M

Question

Complete dominance is absent in

Options

  1. (A) Pisum sativum
  2. (B) Mirabilis jalapa
  3. (C) Lathyrus odoratus
  4. (D) Oenothera lamarckiana

Answer

(B) Mirabilis jalapa

#130 MCQ 1M

Question

If a mother has 'O' blood group, the foetus would die if the blood group of foetus is

Options

  1. (A) A
  2. (B) B
  3. (C) AB
  4. (D) Would remain unaffected by blood group whether it is A, B or AB

Answer

(D) Would remain unaffected by blood group whether it is A, B or AB

#131 MCQ 1M

Question

In one cross between red flower and white flower, the offsprings have red flower in majority and white flowers are much less, then in the cross, red colour character is

Options

  1. (A) Dominant
  2. (B) Assorted
  3. (C) Recessive
  4. (D) Hybrid

Answer

(A) Dominant

#132 MCQ 1M

Question

Organims that are phenotypically similar but genotypically different are said to be

Options

  1. (A) Heterozygous
  2. (B) Monozygous
  3. (C) Multizygous
  4. (D) Homozygous

Answer

(A) Heterozygous

#133 MCQ 1M

Question

Parents of blood group O and AB cannot have a child of group AB because:

Options

  1. (A) Gene O is dominant over gene A
  2. (B) Gene O is dominant over gene B
  3. (C) Gene A or B is absent in one of the parents.
  4. (D) Gene A and B are absent in one of the parents.

Answer

(D) Gene A and B are absent in one of the parents.

#134 MCQ 1M

Question

Which one of the following is a hereditary character of blood?

Options

  1. (A) Blood group
  2. (B) Haeme
  3. (C) Nucleus
  4. (D) None of the above

Answer

(A) Blood group

#135 MCQ 1M

Question

Three children in a family have blood types O, AB and B respectively. What are the genotypes of their parents ?

Options

  1. (A) IAi and IBi
  2. (B) IAIB and ii
  3. (C) IBIB and IAIA
  4. (D) IAIA and IBi

Answer

(A) IAi and IBi

#136 MCQ 1M

Question

A child of a mother with blood group A and a father with blood group AB may have any one of the following blood groups except :

Options

  1. (A) A
  2. (B) B
  3. (C) AB
  4. (D) O

Answer

(D) O

#137 MCQ 1M

Question

Blood grouping in humans is controlled by

Options

  1. (A) 4 alleles in which IA is dominant
  2. (B) 3 alleles in which IA and IB are dominant
  3. (C) 2 alleles in which none is dominant
  4. (D) 3 alleles in which IA is recessive

Answer

(B) 3 alleles in which IA and IB are dominant

#138 MCQ 1M

Question

Which of the following is the significance of dominance?

Options

  1. (A) Organisms with dominant genes are more vital
  2. (B) Harmful mutations are not expressed due to dominant gene
  3. (C) Heterosis is due to the dominant gene
  4. (D) All of the above

Answer

(B) Harmful mutations are not expressed due to dominant gene

#139 MCQ 1M

Question

From a single ear of corn, a farmer planted 200 kernels which produced 140 tall & 40 short plants. The genotypes of these offsprings are most likely to be _______ .

Options

  1. (A) TT, tt
  2. (B) TT, Tt, tt
  3. (C) TT, Tt
  4. (D) Tt, tt

Answer

(B) TT, Tt, tt

#140 MCQ 1M

Question

A useful process for determining whether an individual is homozygous or heterozygous is

Options

  1. (A) Cross-breeding
  2. (B) Self-fertilization
  3. (C) Back-crossing
  4. (D) Test cross

Answer

(D) Test cross

#141 MCQ 1M

Question

Heterozygous tall plants were crossed with dwarf plants. What will be the ratio of dwarf plants in the following progeny?

Options

  1. (A) 50%
  2. (B) 25 %
  3. (C) 75%
  4. (D) 100%

Answer

(A) 50%

#142 MCQ 1M

Question

In the Mirabilis plant the appearance of the pink hybrid (Rr) between a cross of a red (RR) and white (rr) flower parent
indicates _______ .

Options

  1. (A) Segregation
  2. (B) Dominance
  3. (C) Incomplete dominance
  4. (D) Heterosis

Answer

(C) Incomplete dominance

#143 MCQ 1M

Question

The longer the chromosome of an organism, the more genetic variability it gets from, _______ .

Options

  1. (A) Independent assortment
  2. (B) Linkage
  3. (C) Crossing over
  4. (D) Mutation

Answer

(C) Crossing over

#144 MCQ 1M

Question

A cross between hybrid and a parent is known as _______ .

Options

  1. (A) Test cross
  2. (B) Back cross
  3. (C) Monohybrid cross
  4. (D) Reciprocal cross

Answer

(B) Back cross

#145 MCQ 1M

Question

Checkerboard method of calculations was developed by _______ .

Options

  1. (A) Mendel
  2. (B) Bateson
  3. (C) Punnett
  4. (D) Morgan

Answer

(C) Punnett

#146 MCQ 1M

Question

ABO blood groups are controlled by the
gene _______ .

Options

  1. (A) ABO
  2. (B) O
  3. (C) I
  4. (D) i

Answer

(C) I

#147 MCQ 1M

Question

In case of incomplete dominance in F2 generation _______ .

Options

  1. (A) Genotypic ratio is 3 : 1
  2. (B) Phenotypic ratio is 3 : 1
  3. (C) Genotypic ratio = phenotypic ratio
  4. (D) Nothing can be concluded

Answer

(C) Genotypic ratio = phenotypic ratio

#148 MCQ 1M

Question

When Mendel crossed true breeding white-flowered strain of peas with a true breeding red-flowered strain, individuals in the F2 represented _______ .

Options

  1. (A) white-flowered plants
  2. (B) red-flowered plants
  3. (C) red-flowered and white-flowered plants in the ratio 3 : 1
  4. (D) red and white-flowered individuals in the ratio 1 : 1

Answer

(C) red-flowered and white-flowered plants in the ratio 3 : 1

#149 MCQ 1M

Question

A test cross is carried out to _______ .

Options

  1. (A) determine the genotype of a plant at F2
  2. (B) predict whether two traits are linked
  3. (C) assess the number of alleles of a gene
  4. (D) determine whether two species or varieties will breed successfully

Answer

(A) determine the genotype of a plant at F2

#150 MCQ 1M

Question

Mother and father both have blood group 'A'. They have two children one with blood group 'O' and second one with blood group' A'. They have _______ .

Options

  1. (A) mother has homozygotic gene father has heterozygote I'A I A
  2. (B) both are homozygotic (IA IA)
  3. (C) mother is heterozygotic (IAi) and father is homozygotic (IA IA)
  4. (D) both are heterozygotic (IAi)

Answer

(D) both are heterozygotic (IAi)

#151 MCQ 1M

Question

A cross between one tall plant and one dwarf plant resulted in offspring having tall plants. What would be the genotype of offsprings?

Options

  1. (A) TT
  2. (B) Tt
  3. (C) tt
  4. (D) All of the above

Answer

(B) Tt

#152 MCQ 1M

Question

Mendel crossed a pure white-flowered recessive pea plant with a dominant pure red-flowered plant. The first generation of hybrids from the cross should show _______.

Options

  1. (A) 50% white-flowered and 50% red-flowered plants
  2. (B) all red-flowered plants
  3. (C) 75% red-flowered and 25% white-flowered plants
  4. (D) all white-flowered plants

Answer

(B) all red-flowered plants

#153 MCQ 1M ▦ 1

Question

Match the following :

Column I

Column II

1

Inheritance of two genes

a

ABO blood group

2

Incomplete dominance

b

1 : 2 : 1

3

Codominance

c

9 : 3 : 3 : 1

4

Inheritance of one gene

d

3 : 1

Options

  1. (A) 1 – c, 2 – a, 3 – b, 4 – d
  2. (B) 1 – c, 2 – b, 3 – d, 4 – a
  3. (C) 1 – c, 2 – b, 3 – a, 4 – d
  4. (D) 1 – c, 2 – d, 3 – a, 4 – b

Answer

(C) 1 – c, 2 – b, 3 – a, 4 – d

#154 MCQ 1M

Question

Test cross involves

Options

  1. (A) crossing between two genotypes with dominant trait
  2. (B) crossing between two genotypes with recessive trait
  3. (C) crossing between two F1 hybrids
  4. (D) crossing the F1 hybrid with a double recessive genotype.

Answer

(D) crossing the F1 hybrid with a double recessive genotype.

#155 MCQ 1M

Question

Universal donors have no antigens in RBC and have both a and b antibodies. They belong to blood group _______ .

Options

  1. (A) A
  2. (B) B
  3. (C) AB
  4. (D) O

Answer

(D) O

#156 MCQ 1M

Question

A person with blood group 'A' can be given blood of which blood group?

Options

  1. (A) A and B
  2. (B) B and O
  3. (C) A and O
  4. (D) A, B, AB

Answer

(C) A and O

#157 MCQ 1M

Question

Which one of the following blood groups belongs to the category of universal recipient?

Options

  1. (A) AB
  2. (B) A
  3. (C) B
  4. (D) O

Answer

(A) AB

#158 MCQ 1M

Question

Phenotypic ratio 3:1 proves _______ .

Options

  1. (A) Dominance
  2. (B) Segregation
  3. (C) Crossing over
  4. (D) Independent Assortment

Answer

(B) Segregation

#159 MCQ 1M

Question

A child with mother of B blood group and father of AB group blood group, will not have which blood group?

Options

  1. (A) A
  2. (B) B
  3. (C) AB
  4. (D) O

Answer

(D) O

#160 MCQ 1M

Question

When dominant and recessive alleles express themselves together, it is called _______ .

Options

  1. (A) Dominance
  2. (B) Co-dominance
  3. (C) Amphidominance
  4. (D) Pseudodominance

Answer

(B) Co-dominance

#161 MCQ 1M

Question

A man with blood group 'A' marries a woman with blood group 'B'. What are all the possible blood groups of their offsprings?

Options

  1. (A) A, B, AB and O
  2. (B) O only
  3. (C) A and B only
  4. (D) A, B and AB only

Answer

(A) A, B, AB and O

#162 MCQ 1M

Question

When a cross is made between offspring and its parents, it is known as _______ .

Options

  1. (A) monohybrid cross
  2. (B) dihybrid cross
  3. (C) back cross
  4. (D) reciprocal cross

Answer

(C) back cross

#163 MCQ 1M

Question

Which of the following is genotypic ratio of F2 Mendel's monohybrid cross?

Options

  1. (A) 1 : 3
  2. (B) 3 : 1
  3. (C) 1 : 2 : 1
  4. (D) 1 : 1 : 1 : 1

Answer

(C) 1 : 2 : 1

#164 MCQ 1M

Question

Blood group of the father is A and blood group of mother is B. Then predict the blood group of the progeny.

Options

  1. (A) A, AB
  2. (B) A, B, AB, O
  3. (C) B, AB
  4. (D) A, B, AB

Answer

(B) A, B, AB, O

#165 MCQ 1M

Question

Genotype of blood group 'A' will be

Options

  1. (A) IAIA
  2. (B) IBIB
  3. (C) IAIA or IAIO
  4. (D) IAIO

Answer

(C) IAIA or IAIO

#166 MCQ 1M

Question

A child's blood group is 'O'. The parents blood groups cannot be _______ .

Options

  1. (A) AB and O
  2. (B) B and O
  3. (C) A and B
  4. (D) A and A

Answer

(A) AB and O

#167 MCQ 1M

Question

In a family, the father has a blood group ‘A’ and the mother has a blood group ‘B’, Children show 50% probability for a blood group “AB” indicate that _______ .

Options

  1. (A) father is heterozygous
  2. (B) mother is heterozygous
  3. (C) either of the parent is heterozygous
  4. (D) mother is homozygous

Answer

(C) either of the parent is heterozygous

#168 MCQ 1M

Question

How many different kind of phenotypic form will be obtained if we arrange Mendel's dihybrid experiment result in Punnett 16 square boxes?

Options

  1. (A) 8
  2. (B) 4
  3. (C) 2
  4. (D) 16

Answer

(B) 4

#169 MCQ 1M

Question

How many different genotypic forms of four different kinds of phenotypic plants will be obtained in F2 generation of Mendel's dihybrid experiment?

Options

  1. (A) 16
  2. (B) 4
  3. (C) 8
  4. (D) 9

Answer

(D) 9

#170 MCQ 1M

Question

How many genotypes of RrYy are there in F2 generation of dihybrid experiment ?

Options

  1. (A) 3
  2. (B) 2
  3. (C) 4
  4. (D) 9

Answer

(C) 4

#171 MCQ 1M

Question

How many genotypes of rryy are obtained in F2 generation of dihybrid experiment?

Options

  1. (A) 1
  2. (B) 4
  3. (C) 2
  4. (D) 3

Answer

(A) 1

#172 MCQ 1M

Question

What type of gametes will be formed by genotype RrYy?

Options

  1. (A) RY, Ry, rY, ry
  2. (B) RY, Ry, ry, ry
  3. (C) Ry, Ry, ry
  4. (D) Rr, RR, Yy, YY

Answer

(A) RY, Ry, rY, ry

#173 MCQ 1M

Question

In dihybrid cross, the factor for yellow colour assorts out independently of the factors for :

Options

  1. (A) Green colour
  2. (B) Round shape
  3. (C) Wrinkle shape
  4. (D) Long shape

Answer

(B) Round shape

#174 MCQ 1M

Question

In order to calculate map distance of genes on a chromosomes, one must know the

Options

  1. (A) Number of mutant genes
  2. (B) Recombination frequency of each gene locus
  3. (C) Cross over percentage
  4. (D) Non-cross over percentage

Answer

(C) Cross over percentage

#175 MCQ 1M

Question

What will be the number of linkage groups in maize if it has 10 pairs of chromosomes?

Options

  1. (A) 5
  2. (B) 10
  3. (C) 0
  4. (D) 20

Answer

(B) 10

#176 MCQ 1M

Question

Distance between two linked genes on a chromosome measured in cross over units, is

Options

  1. (A) Ratio of crossing over between them
  2. (B) Cross-over value
  3. (C) Number of other genes between them
  4. (D) None of these

Answer

(B) Cross-over value

#177 MCQ 1M

Question

When the tall plants with red flowers were crossed with dwarf plants having white flowers, Mendel found the ratio of progeny is

Options

  1. (A) 1 : 2 : 1
  2. (B) 3 : 1
  3. (C) 9 : 3 : 3 : 1
  4. (D) 1 : 4 : 6 : 4 : 1

Answer

(C) 9 : 3 : 3 : 1

#178 MCQ 1M

Question

Mendel's law of independent assortment is applicable for

Options

  1. (A) All genes in all organism
  2. (B) All genes of pea plant only
  3. (C) All linked genes only
  4. (D) All non-linked genes only

Answer

(D) All non-linked genes only

#179 MCQ 1M

Question

In Mendelian, linkage was not observed due to

Options

  1. (A) Mutation
  2. (B) Independent assortment
  3. (C) Synapsis
  4. (D) Crossing over

Answer

(B) Independent assortment

#180 MCQ 1M

Question

In a dihybrid cross between RRYY and rryy, the number of RrYy F2 genotypes will
be _______ .

Options

  1. (A) 4
  2. (B) 3
  3. (C) 2
  4. (D) 9

Answer

(A) 4

#181 MCQ 1M 🖼 1

Question

The map distance between genes A and B is 3 units, between B and C 10 units and between C and A, 7 units. The order of the genes in a linkage map constructed on the above data would perhaps be _______ .

Options

  1. (A) A, B, C
  2. (B) A, C, B
  3. (C) B,C, A
  4. (D) B,A, C

Answer

(D) B,A, C

#182 MCQ 1M

Question

The frequency of recombination between gene pairs on the same chromosome as a measure of the distance between genes was explained by _______ .

Options

  1. (A) T.H. Morgan
  2. (B) Gregor J. Mendel
  3. (C) Alfred Sturtevant
  4. (D) Sutton Boveri

Answer

(C) Alfred Sturtevant

#183 MCQ 1M

Question

If haploid chromosome number in a cell is 12. The monosomic number will be _______ .

Options

  1. (A) 24
  2. (B) 21
  3. (C) 25
  4. (D) 23

Answer

(D) 23

#184 MCQ 1M

Question

Experimental verification of the chromosomal theory of inheritance was done by _______ .

Options

  1. (A) Morgan
  2. (B) Mendel
  3. (C) Sutton
  4. (D) Boveri

Answer

(A) Morgan

#185 MCQ 1M

Question

Mendel's law of independent assortment is based on F2 ratio of _______ .

Options

  1. (A) 1 : 2 : 1
  2. (B) 9 : 3 : 3 : 1
  3. (C) 2 : 1
  4. (D) 3 : 1

Answer

(B) 9 : 3 : 3 : 1

#186 MCQ 1M

Question

In maize, chromosome number is 2n = 20. The number of linkage groups in it shall
be _______ .

Options

  1. (A) 20
  2. (B) 40
  3. (C) 10
  4. (D) 5

Answer

(C) 10

#187 MCQ 1M

Question

What is the ratio of homozygous plants for both dominant characters in F2 of a dihybrid cross?

Options

  1. (A) 1/16
  2. (B) 3/16
  3. (C) 4/16
  4. (D) 9/16

Answer

(A) 1/16

#188 MCQ 1M

Question

1: 1: 1: 1 ratio shows _______ .

Options

  1. (A) Monohybrid cross
  2. (B) Dihybrid cross
  3. (C) Back cross
  4. (D) Dihybrid test cross

Answer

(D) Dihybrid test cross

#189 MCQ 1M

Question

Types of phenotypes of the F2 generation of dihybrid cross?

Options

  1. (A) 4
  2. (B) 16
  3. (C) 8
  4. (D) 9

Answer

(A) 4

#190 MCQ 1M

Question

Genetic recombinations occur through

Options

  1. (A) Mitosis & fertilization
  2. (B) Mitosis & Meiosis
  3. (C) Meiosis & fertilization
  4. (D) None

Answer

(C) Meiosis & fertilization

#191 MCQ 1M

Question

Which of the following is the unit of inheritance?

Options

  1. (A) Phenotype
  2. (B) Genotype
  3. (C) Gene
  4. (D) Genome

Answer

(C) Gene

#192 MCQ 1M

Question

If there were only parental combinations in F2 generation of a dihybrid cross then Mendel might have discovered :

Options

  1. (A) Independent assortment
  2. (B) Atavism
  3. (C) Linkage
  4. (D) Repulsion

Answer

(C) Linkage

#193 MCQ 1M

Question

If the distance between the genes on the chromosome is more, then the gene shows _______ .

Options

  1. (A) less linkage
  2. (B) strong linkage
  3. (C) weak linkage
  4. (D) incomplete linkage

Answer

(C) weak linkage

#194 MCQ 1M

Question

Which of the following conditions represents a case of codominant genes?

Options

  1. (A) A gene expresses itself, suppressing the phenotypic effect of its alleles.
  2. (B) Genes that are similar in phenotypic effect when present separately, but together interact to produce a different trait.
  3. (C) Alleles, both of which interact to produce an effect in homozygous condition.
  4. (D) Alleles, both of which interact to produce an independent effect in heterozygous conditions.

Answer

(D) Alleles, both of which interact to produce an independent effect in heterozygous conditions.

#195 MCQ 1M

Question

Crossing over during meiosis occurs between

Options

  1. (A) Sister chromatids
  2. (B) Non-sister chromatids
  3. (C) Centromeres
  4. (D) Non-homologous chromosomes

Answer

(B) Non-sister chromatids

#196 MCQ 1M

Question

Incomplete linkage in Drosophila produces offsprings with parental and non-parental combinations. State the percentage of the non-parental combination in Drosophila.

Options

  1. (A) 83%
  2. (B) 17 %
  3. (C) 15 %
  4. (D) 85 %

Answer

(B) 17 %

#197 MCQ 1M

Question

What does the term recombination describe?

Options

  1. (A) Generation of non-parental gene combination
  2. (B) Generation of parental gene combination
  3. (C) Generation of internal gene combination
  4. (D) All of the above

Answer

(A) Generation of non-parental gene combination

#198 MCQ 1M

Question

In T. H. Morgan’s Experiment on Drosophila, what will be the result when F1 female flies are crossed with double recessive male flies?
17% recombinations
58.5% recombinations
40% recombinations
10% Recombinations

Options

  1. (A) 83% parental combinations
  2. (B) 41.5% parental combinations
  3. (C) 60% parental combinations
  4. (D) 90% parental combinations

Answer

(A) 83% parental combinations

#199 MCQ 1M

Question

Which cross yielded a ratio of 7:1 :1:7?

Options

  1. (A) Test cross (Dihybrid) – Bateson and Punnet
  2. (B) Test cross (Monohybrid) – Bateson and Punnet
  3. (C) Test cross (Dihybrid) – Carrel Correns
  4. (D) Test cross (Dihybrid) – Mendel & Morgan

Answer

(A) Test cross (Dihybrid) – Bateson and Punnet

#200 MCQ 1M

Question

An exception to Mendel's law is _______ .

Options

  1. (A) law of independent assortment
  2. (B) law of segregation
  3. (C) law of dominance
  4. (D) law of linkage

Answer

(D) law of linkage

#201 MCQ 1M

Question

When there is no possibility of an independent assortment of genes during gametogenesis then what will be the real ratio of F2 in dihybrid cross?

Options

  1. (A) 9 : 3 : 3 : 1
  2. (B) 11 : 1 : 1 : 3
  3. (C) 12 : 1 : 1 : 2
  4. (D) 9 : 3 : 2 : 2

Answer

(B) 11 : 1 : 1 : 3

#202 MCQ 1M

Question

What was the expected ratio of F2 by Bateson and Punnett in their dihybridization experiment done on Lathyrus odoratus?

Options

  1. (A) 9 : 3 : 3 : 1
  2. (B) 11 : 1 : 1 : 3
  3. (C) 12 : 1 : 1 : 3
  4. (D) 9 : 3 : 2 : 2

Answer

(A) 9 : 3 : 3 : 1

#203 MCQ 1M

Question

If a plant heterozygous for tallness is selfed, the F2 generation has both tall and dwarf plants. This proves the principle of _______ .

Options

  1. (A) Dominance
  2. (B) Segregation
  3. (C) Independent assortment
  4. (D) Incomplete dominance

Answer

(B) Segregation

#204 MCQ 1M

Question

A dihybrid for qualitative trait is crossed with homozygous recessive individual of its type, the phenotypic ratio is _______ .

Options

  1. (A) 1 : 2 : 1
  2. (B) 3 : 1
  3. (C) 1 : 1 : 1 : 1
  4. (D) 9 : 3 : 3 : 1

Answer

(C) 1 : 1 : 1 : 1

#205 MCQ 1M

Question

A human male produces sperms with the genotypes AB, Ab, aB, ab pertaining to two diallelic characters in equal proportions. What is the corresponding genotype of this person?

Options

  1. (A) AaBB
  2. (B) AABb
  3. (C) AABB
  4. (D) AaBb

Answer

(D) AaBb

#206 MCQ 1M

Question

On selfing a plant of F1-generation with genotype "AABbCC', the genotypic ratio in F2-generation will be

Options

  1. (A) 3 : 1
  2. (B) 1 : 1
  3. (C) 9 : 3 : 3 : 1
  4. (D) 27 : 9 : 9 : 9 : 3 : 3 : 3 : 1

Answer

(A) 3 : 1

#207 MCQ 1M

Question

In human beings, multiple genes are involved in the inheritance of _______.

Options

  1. (A) sickle-cell anaemia
  2. (B) skin colour
  3. (C) colour blindness
  4. (D) phenylketonuria

Answer

(B) skin colour

#208 MCQ 1M

Question

How many different types of genetically different gametes will be produced by a heterozygous plant having the genotype AABbCc?

Options

  1. (A) Six
  2. (B) Nine
  3. (C) Two
  4. (D) Four

Answer

(D) Four

#209 MCQ 1M

Question

The polygenic genes show

Options

  1. (A) different karyotypes
  2. (B) different genotypes
  3. (C) different phenotypes
  4. (D) none of these

Answer

(C) different phenotypes

#210 MCQ 1M

Question

A polygenic inheritance in human beings is

Options

  1. (A) skin colour
  2. (B) phenylketonuria
  3. (C) colour blindness
  4. (D) sickle cell anaemia

Answer

(A) skin colour

#211 MCQ 1M

Question

Inheritance of skin colour in humans is an example of

Options

  1. (A) point mutation
  2. (B) polygenic inheritance
  3. (C) codominance
  4. (D) chromosomal aberration

Answer

(B) polygenic inheritance

#212 MCQ 1M

Question

How many different kinds of gametes will be produced by a plant having the genotype AABbCC?

Options

  1. (A) Two
  2. (B) Three
  3. (C) Four
  4. (D) Nine

Answer

(A) Two

#213 MCQ 1M

Question

Which one of the following is an example of polygenic inheritance?

Options

  1. (A) Skin colour in humans
  2. (B) Flower colour in Mirabilis jalapa
  3. (C) Production of male honeybee
  4. (D) Pod shape in garden pea

Answer

(A) Skin colour in humans

#214 MCQ 1M

Question

What is called pleiotropism?

Options

  1. (A) Phenomenon of multiple effects of a single gene
  2. (B) Phenomenon of multiple effects of multiple genes
  3. (C) Phenomenon of multiple effects of multiple alleles
  4. (D) all of the above

Answer

(A) Phenomenon of multiple effects of a single gene

#215 MCQ 1M

Question

A pleiotropic gene is one which _______ .

Options

  1. (A) affects one character
  2. (B) affects more than one characters
  3. (C) and (B) both
  4. (D) None of these

Answer

(B) affects more than one characters

#216 MCQ 1M

Question

A pleiotropic gene _______ .

Options

  1. (A) controls a trait only in combination with another gene.
  2. (B) controls multiple traits in an individual.
  3. (C) is expressed only in primitive plants.
  4. (D) is a gene evolved during pliocene.

Answer

(B) controls multiple traits in an individual.

#217 MCQ 1M

Question

XO type of sex determination can be found in:

Options

  1. (A) Birds
  2. (B) Grasshoppers
  3. (C) Monkeys
  4. (D) Drosophila

Answer

(B) Grasshoppers

#218 MCQ 1M

Question

In human being sex chromosomal complement is _______ .

Options

  1. (A) XX – XY
  2. (B) XX – XO
  3. (C) ZO – ZZ
  4. (D) ZW – ZZ

Answer

(A) XX – XY

#219 MCQ 1M

Question

Which one of the following conditions correctly describes the manner of determining the sex?

Options

  1. (A) Homozygous sex chromosomes (ZZ) determine female sex in birds.
  2. (B) XO type of sex chromosomes determine male sex in grasshopper.
  3. (C) XO condition in humans as found in Turner’s syndrome determines female sex.
  4. (D) Homozygous sex chromosomes (XX) produce males in Drosophila.

Answer

(B) XO type of sex chromosomes determine male sex in grasshopper.

#220 MCQ 1M

Question

What type of sex determination is observed in grasshopper?

Options

  1. (A) XX - XY type
  2. (B) XX - XO type
  3. (C) ZZ - ZW type
  4. (D) ZZ - ZO type

Answer

(B) XX - XO type

#221 MCQ 1M

Question

Drosophila flies with one half of the body male and other half female is referred to as

Options

  1. (A) Gynandromorph
  2. (B) Hermaphrodite
  3. (C) Super female
  4. (D) Intersex

Answer

(A) Gynandromorph

#222 MCQ 1M

Question

The average ratio of male to female individuals based on XX and XY type of sex determination in total world of human population is

Options

  1. (A) 3 : 1
  2. (B) 1 : 3
  3. (C) 1 : 4
  4. (D) 1 : 1

Answer

(D) 1 : 1

#223 MCQ 1M

Question

It is a mutagen.

Options

  1. (A) Cold
  2. (B) Heat
  3. (C) Water
  4. (D) UV radiation

Answer

(D) UV radiation

#224 MCQ 1M

Question

The character of organisms is said to be sex linked when its gene is carried on _______ .

Options

  1. (A) Y chromosomes
  2. (B) X chromosome of male or female
  3. (C) X and Y chromosomes
  4. (D) A particular autosome

Answer

(B) X chromosome of male or female

#225 MCQ 1M

Question

One of the parents of a cross has a mutation in its mitochondria. In that cross, that parent is taken as a male. During segregation of F2 progenies that mutation is found in

Options

  1. (A) One-third of the progenies
  2. (B) None of the progenies
  3. (C) All the progenies
  4. (D) Fifty percent of the progenies

Answer

(B) None of the progenies

#226 MCQ 1M

Question

The most striking example of point mutation is found in a disease called

Options

  1. (A) Down's syndrome
  2. (B) Sickle cell anaemia
  3. (C) Thalassemia
  4. (D) Night blindness

Answer

(B) Sickle cell anaemia

#227 MCQ 1M

Question

A man who carries a sex linked gene on his Y chromosome will transmit this gene to ______.

Options

  1. (A) half of his sons
  2. (B) half of his daughters
  3. (C) all his sons
  4. (D) all his daughters

Answer

(C) all his sons

#228 MCQ 1M

Question

Euploidy is best explained by

Options

  1. (A) Exact multiples of a haploid set of chromosomes
  2. (B) One chromosome less than the haploid set of chromosome
  3. (C) One chromosome more than the haploid set of chromosomes
  4. (D) One chromosome more than the diploid set of chromosome

Answer

(D) One chromosome more than the diploid set of chromosome

#229 MCQ 1M

Question

XO-chromosomal abnormality in human beings causes.

Options

  1. (A) Turner's syndrome
  2. (B) Down's syndrome
  3. (C) Klinefelter's syndrome
  4. (D) None of these

Answer

(A) Turner's syndrome

#230 MCQ 1M

Question

A couple has four daughters. The percentage probability of the fifth child to be a daughter
is _______ .

Options

  1. (A) 10
  2. (B) 50
  3. (C) 75
  4. (D) 100

Answer

(B) 50

#231 MCQ 1M

Question

If both parents are carriers for thalassemia, which is an autosomal recessive disorder, what are the chances of pregnancy resulting in an affected child?

Options

  1. (A) 50%
  2. (B) 25%
  3. (C) 100%
  4. (D) no chance

Answer

(B) 25%

#232 MCQ 1M

Question

Sex linked disease is _______ .

Options

  1. (A) Haemophilia
  2. (B) Colour blindness
  3. (C) Sickle-cell anaemia
  4. (D) Both (A) and (B)

Answer

(D) Both (A) and (B)

#233 MCQ 1M

Question

If a colourblind lady marries a normal man, their children will be _______ .

Options

  1. (A) Normal daughters and normal sons
  2. (B) Normal sons and carrier daughters
  3. (C) Colourblind sons and carrier daughters
  4. (D) Colourblind sons and colourblind daughters

Answer

(C) Colourblind sons and carrier daughters

#234 MCQ 1M

Question

A woman with two genes for haemophillia and one gene for colour blindness on one of the X chromosomes marries a normal man. How will the progeny be?

Options

  1. (A) All sons and daughters will be haemophillic and colourblind.
  2. (B) Haemophillic and colourblind daughters.
  3. (C) 50% haemophillic colourblind sons and 50% normal sons.
  4. (D) 50% haemophillic daughters and 50% colourblind daughters.

Answer

(C) 50% haemophillic colourblind sons and 50% normal sons.

#235 MCQ 1M

Question

If a normal woman marries a colourblind man, then their _______ .

Options

  1. (A) all sons will be colourblind and daughters normal
  2. (B) all daughters will be colourblind and sons normal
  3. (C) all children will be normal
  4. (D) all children will be colourblind

Answer

(C) all children will be normal

#236 MCQ 1M

Question

Haemophilia is :

Options

  1. (A) Autosomal
  2. (B) Y-linked
  3. (C) Z-linked
  4. (D) X-linked

Answer

(D) X-linked

#237 MCQ 1M

Question

If a haemophilic man marries a woman carrier (heterozygous) for haemophilia, what would be the possibility that their daughter to be haemophilic?

Options

  1. (A) 100%
  2. (B) 75%
  3. (C) 50%
  4. (D) 0%

Answer

(C) 50%

#238 MCQ 1M

Question

In which of the following colour blindness is inherited?

Options

  1. (A) In males only
  2. (B) In females only
  3. (C) In both males and females
  4. (D) In none of the above

Answer

(C) In both males and females

#239 MCQ 1M

Question

All sons of a couple are colourblind
because _______ .

Options

  1. (A) mother is homozygous colourblind
  2. (B) mother is heterozygous and father normal
  3. (C) mother is heterozygous and father colourblind
  4. (D) mother is normal and father colourblind

Answer

(A) mother is homozygous colourblind

#240 MCQ 1M

Question

A colourblind man marries a woman with normal sight who has no history of colour blindness in her family. What is the probability of their grandson being colourblind?

Options

  1. (A) Nil
  2. (B) 0.25
  3. (C) 0.5
  4. (D) 1

Answer

(B) 0.25

#241 MCQ 1M

Question

Which one of the following is a genetically transmitted character?

Options

  1. (A) Colour blindness
  2. (B) Hydrocephalus
  3. (C) Hemophilia
  4. (D) All of these

Answer

(D) All of these

#242 MCQ 1M

Question

In man, which of the following genotypes and phenotypes may be the correct result of aneuploidy in sex chromosomes?

Options

  1. (A) 22 pairs + XXY males
  2. (B) 22 pairs + XX females
  3. (C) 22 pairs + XXYY females
  4. (D) 22 pairs + Y females

Answer

(A) 22 pairs + XXY males

#243 MCQ 1M

Question

If a colour blind female marries a man whose mother was also colour blind, what are the chances of her progeny having blindness ?

Options

  1. (A) 50%
  2. (B) 75%
  3. (C) 100%
  4. (D) 25%

Answer

(C) 100%

#244 MCQ 1M

Question

Carrier of genes of colour blindness are present in :

Options

  1. (A) Father
  2. (B) Mother
  3. (C) Father and mother
  4. (D) None

Answer

(B) Mother

#245 MCQ 1M

Question

In a cross between a male and female, both heterozygous are sickle cell anaemia gene, what percentage of the progeny will be diseased?

Options

  1. (A) 50
  2. (B) 75
  3. (C) 25
  4. (D) 100

Answer

(C) 25

#246 MCQ 1M

Question

Number of sex chromosomes is normal in

Options

  1. (A) Super females
  2. (B) Turner's syndrome
  3. (C) Klinefelter's syndrome
  4. (D) Down's syndrome

Answer

(D) Down's syndrome

#247 MCQ 1M

Question

Colour blindness is found more in males than in females because :

Options

  1. (A) The males containing the single affected X-chromosome are colour blind
  2. (B) Heterozygous females are colour blind
  3. (C) Males having affected Y-chromosome are colour blind
  4. (D) Affected X-chromosome has much higher affinity to Y-chromosome ans compared to unaffected chromosomes to exhibit the same.

Answer

(A) The males containing the single affected X-chromosome are colour blind

#248 MCQ 1M

Question

A normal woman, whose father was colour-blind is married to a normal man. The sons would be :

Options

  1. (A) All normal
  2. (B) All color blind
  3. (C) 75% colour blind
  4. (D) 50% colour blind

Answer

(D) 50% colour blind

#249 MCQ 1M

Question

A man whose father was colour blind marries a woman who had a colour blind mother and normal father. What percentage of male children of this couple will be colour blind?

Options

  1. (A) 25
  2. (B) 0
  3. (C) 50
  4. (D) 75

Answer

(C) 50

#250 MCQ 1M

Question

A normal woman whose father was colourblind marries a normal man. What kinds of children would be expected and in what proportion ?

Options

  1. (A) Daughters normal, 50% of sons colourblind
  2. (B) Daughters normal, all sons colourblind
  3. (C) 50% of daughters colourblind, all sons normal
  4. (D) All daughters colourblind, sons normal

Answer

(A) Daughters normal, 50% of sons colourblind

#251 MCQ 1M

Question

The amino acid substituted in sickle cell anaemia is

Options

  1. (A) Glutamic acid for valline in the alpha chain
  2. (B) Glutamic acid for valline in the beta chain
  3. (C) Valine for glutamic acid in the alpha chain
  4. (D) Valine for glutamic acid in the beta chain.

Answer

(D) Valine for glutamic acid in the beta chain.

#252 MCQ 1M

Question

Albinism is

Options

  1. (A) Hereditary character
  2. (B) Non-hereditary character
  3. (C) Sex-linked character
  4. (D) Acquired character

Answer

(A) Hereditary character

#253 MCQ 1M

Question

The number of chromosomes in Tuner's syndrome is

Options

  1. (A) 45
  2. (B) 43
  3. (C) 44
  4. (D) 42

Answer

(A) 45

#254 MCQ 1M

Question

Haemophilic female marries normal male, the theoretical ratio of their offsprings regarding haemophilia will be

Options

  1. (A) All offsprings are haemophilic
  2. (B) All girls are haemophilic
  3. (C) All sons are haemophilic
  4. (D) Half daughters and halfsons are haemophilic

Answer

(C) All sons are haemophilic

#255 MCQ 1M

Question

Haemophilia is a

Options

  1. (A) Deficiency disorder
  2. (B) Y-linked disorder
  3. (C) X-Linked recessive disorder
  4. (D) Autosomal recessive

Answer

(C) X-Linked recessive disorder

#256 MCQ 1M

Question

Colour blindness in man is

Options

  1. (A) Due of deficiency of VitaminA
  2. (B) Due of absence of visual purple in retina
  3. (C) Due to absence of rods in retina
  4. (D) A sex linked abnormality

Answer

(D) A sex linked abnormality

#257 MCQ 1M

Question

Colour blindness is caused by a single _______.

Options

  1. (A) Dominant gene in woman
  2. (B) Dominant gene in man
  3. (C) Recessive gene in man
  4. (D) Recessive gene in woman

Answer

(C) Recessive gene in man

#258 MCQ 1M

Question

Which one is a sex-linked disease?

Options

  1. (A) Tylosis
  2. (B) Beri-beri
  3. (C) Colour blindness
  4. (D) Albinism

Answer

(C) Colour blindness

#259 MCQ 1M

Question

A normal woman whose father was colourblind, is married to a normal man. The sons would be _______ .

Options

  1. (A) 75% colour blind
  2. (B) 50% colour blind
  3. (C) all normal
  4. (D) all colour blind

Answer

(B) 50% colour blind

#260 MCQ 1M

Question

The traits controlled by the genes located on X chromosome of human beings are said to
be _______ .

Options

  1. (A) Sex linked
  2. (B) Sex influenced
  3. (C) Sex limited
  4. (D) None of these

Answer

(A) Sex linked

#261 MCQ 1M

Question

Assertion : Phenylketonuria is a recessive hereditary disease caused by body's failure to oxidize an amino acid phenylalanine to tyrosine, because of a defective enzyme.
Reason : It results in the presence of phenylpyruvic acid in urine.

Options

  1. (A) Both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion
  2. (B) Both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
  3. (C) The Assertion is correct but reason is incorrect.
  4. (D) Both the Assertion and reason are incorrect.

Answer

(B) Both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

#262 MCQ 1M

Question

Assertion : Colour blindness occurs about 0.4 percent in the females.
Reason : Red-green colour blindness gene is present in the X-chromosome.

Options

  1. (A) A and R both are correct, and R is correct explanation of A.
  2. (B) A and R both are correct, but R is not correct explanation of A.
  3. (C) A is correct, but R is wrong
  4. (D) A is wrong, but R is correct

Answer

(A) A and R both are correct, and R is correct explanation of A.

#263 MCQ 1M

Question

Assertion : Seven contrasting traits in pea plant were studied by Mendel.
Reason : Mendel had performed several hybridization experiments.

Options

  1. (A) A and R both are correct, and R is correct explanation of A.
  2. (B) A and R both are correct, but R is not correct explanation of A.
  3. (C) A is correct, but R is wrong
  4. (D) A is wrong, but R is correct

Answer

(A) A and R both are correct, and R is correct explanation of A.

#264 MCQ 1M

Question

Assertion : Mendel studied height of stem, flower colour, position of flower, shape of pod, pod colour and colour of seed types of characteristics.
Reason : Mendel carried out experiments using certain method like emasculation and bagging.

Options

  1. (A) A and R both are correct, and R is correct explanation of A.
  2. (B) A and R both are correct, but R is not correct explanation of A.
  3. (C) A is correct, but R is wrong
  4. (D) A is wrong, but R is correct

Answer

(B) A and R both are correct, but R is not correct explanation of A.

#265 MCQ 1M

Question

Assertion : In monohybrid cross done by Mendel, the phenotype ratio is 3 : 1.
Reason : In monohybrid cross performed by Mendel, F2 generation show 3 Tall plant and 1 dwarf plant.

Options

  1. (A) A and R both are correct, and R is correct explanation of A.
  2. (B) A and R both are correct, but R is not correct explanation of A.
  3. (C) A is correct, but R is wrong
  4. (D) A is wrong, but R is correct

Answer

(A) A and R both are correct, and R is correct explanation of A.

#266 MCQ 1M

Question

Assertion : The pink flower in Snapdragon is an example of incomplete dominance.
Reason : In incomplete dominance, both the alleles do not completely dominate each other.

Options

  1. (A) A and R both are correct, and R is correct explanation of A.
  2. (B) A and R both are correct, but R is not correct explanation of A.
  3. (C) A is correct, but R is wrong
  4. (D) A is wrong, but R is correct

Answer

(A) A and R both are correct, and R is correct explanation of A.

#267 MCQ 1M

Question

Assertion : ABO blood group example of co-dominance.
Reason : When IA and IB alleles are present then both are dominant and express themselves.

Options

  1. (A) A and R both are correct, and R is correct explanation of A.
  2. (B) A and R both are correct, but R is not correct explanation of A.
  3. (C) A is correct, but R is wrong
  4. (D) A is wrong, but R is correct

Answer

(A) A and R both are correct, and R is correct explanation of A.

#268 MCQ 1M

Question

Assertion : The male honey bee (drone) has 16 chromosome.
Reason : In honey bee, drone is haploid.

Options

  1. (A) A and R both are correct, and R is correct explanation of A.
  2. (B) A and R both are correct, but R is not correct explanation of A.
  3. (C) A is correct, but R is wrong
  4. (D) A is wrong, but R is correct

Answer

(A) A and R both are correct, and R is correct explanation of A.

#269 MCQ 1M

Question

Assertion : In human, the colour of skin is an example of polygenic inheritance.
Reason : The colour of skin in human is regulated by A, B, C gene.

Options

  1. (A) A and R both are correct, and R is correct explanation of A.
  2. (B) A and R both are correct, but R is not correct explanation of A.
  3. (C) A is correct, but R is wrong
  4. (D) A is wrong, but R is correct

Answer

(A) A and R both are correct, and R is correct explanation of A.

#270 MCQ 1M

Question

Assertion : Mendel's dihybrid experiment has phenotypic ratio 9 : 3 : 3 : 1.
Reason : Two traits are studied in dihybrid cross.

Options

  1. (A) A and R both are correct, and R is correct explanation of A.
  2. (B) A and R both are correct, but R is not correct explanation of A.
  3. (C) A is correct, but R is wrong
  4. (D) A is wrong, but R is correct

Answer

(A) A and R both are correct, and R is correct explanation of A.

#271 MCQ 1M

Question

Assertion : Down's syndrome is caused by trisomy of 21.
Reason : There are 45 chromosomes in a Down's syndrome.

Options

  1. (A) A and R both are correct, and R is correct explanation of A.
  2. (B) A and R both are correct, but R is not correct explanation of A.
  3. (C) A is correct, but R is wrong
  4. (D) A is wrong, but R is correct

Answer

(C) A is correct, but R is wrong

#272 MCQ 1M

Question

Assertion : Sickle-cell anemia is an example of point mutation.
Reason : In sickle cell anemia, blood clotting mechanism is affected.

Options

  1. (A) A and R both are correct, and R is correct explanation of A.
  2. (B) A and R both are correct, but R is not correct explanation of A.
  3. (C) A is correct, but R is wrong
  4. (D) A is wrong, but R is correct

Answer

(C) A is correct, but R is wrong

#273 MCQ 1M 🖼 1

Question

The following pedigree analysis represents __________ .

Options

  1. (A) Sex-linked, inborn metabolic error such as phenyl ketonuria
  2. (B) Autosomal-linked recessive trait such as phenyl ketonuria
  3. (C) The given pedigree chart is wrong because this is not possible
  4. (D) Sex-linked recessive disorder such as haemophilia

Answer

(D) Sex-linked recessive disorder such as haemophilia

#274 MCQ 1M 🖼 1

Question

Choose correct option for given experiment.

Test cross

Phenotypic ratio

(A)

2 : 1

9 : 3 : 3 : 1

(B)

1 : 1 : 1 : 1

9 : 3 : 3 : 1

(C)

9 : 3 : 3 : 1

1 : 1 : 1 : 1

(D)

3 : 1

1 : 1

Answer

(B)

1 : 1 : 1 : 1

9 : 3 : 3 : 1

#275 MCQ 1M 🖼 4

Question

Which of the following option show recombinations?

Options

  1. (A)
  2. (B)
  3. (C)
  4. (D)

Answer

(C)

#276 MCQ 1M 🖼 1

Question

Identify the following Pedigree.

Options

  1. (A) Autosomal dominant trait
  2. (B) Autosomal recessive trait
  3. (C) Sex-linked dominant trait
  4. (D) Sex-linked recessive trait

Answer

(A) Autosomal dominant trait

#277 MCQ 1M 🖼 1

Question

Choose the correct option regarding following pedigree chart.

Options

  1. (A) Pedigree of phenylketonuria like autosomal recessive trait
  2. (B) Pedigree of phenylketonuria like in born metabolic sex-linked disorder
  3. (C) Pedigree for sex-linked disease such as haemophilia
  4. (D) The given pedigree is not possible

Answer

(A) Pedigree of phenylketonuria like autosomal recessive trait

#278 MCQ 1M 🖼 1

Question

Pedigree chart represents inheritance of certain trait present in human, then choose the correct option for the given chart.

Options

  1. (A) Autosomal dominant trait
  2. (B) Autosomal recessive trait
  3. (C) Sex-linked recessive trait
  4. (D) Sex-linked dominant trait

Answer

(B) Autosomal recessive trait

#279 MCQ 1M 🖼 1

Question

What is represented by given pedigree?

Options

  1. (A) X-linked recessive
  2. (B) Paternal inheritance
  3. (C) Autosomal recessive
  4. (D) Maternal inheritance

Answer

(D) Maternal inheritance

#280 MCQ 1M 🖼 1

Question

What is presented by following pedigree?

Options

  1. (A) Dominant inheritance
  2. (B) Recessive inheritance
  3. (C) Sex-linked recessive inheritance
  4. (D) Cytoplasmic inheritance

Answer

(C) Sex-linked recessive inheritance

#281 MCQ 1M 🖼 1

Question

Choose the correct option for the following experiment.

Genotypic ratio

Phenotypic ratio

(A)

2 : 2

1 : 1

(B)

3 : 1

2 : 1

(C)

1 : 2 : 1

3 : 1

(D)

9 : 3 : 3 : 1

1 : 1

Answer

(C)

1 : 2 : 1

3 : 1

#282 MCQ 1M 🖼 4

Question

Choose the correct option regarding symbols used in the human pedigree analysis.

Options

  1. (A) Mating between relatives
  2. (B) Unaffected male
  3. (C) Unaffected female
  4. (D) Affected male

Answer

(A) Mating between relatives

#283 MCQ 1M 🖼 1

Question

Which disorder is represented by given diagram ?

Options

  1. (A) Klinefelter's syndrome
  2. (B) Turner's syndrome
  3. (C) Down's syndrome
  4. (D) Cri-du-chat syndrome

Answer

(C) Down's syndrome

#284 MCQ 1M 🖼 1

Question

The following diagram represents sex determination in honey bee. How many chromosomes are there in P, Q and R?

Options

  1. (A) 16, 16, 32
  2. (B) 16, 8, 24
  3. (C) 32, 16, 32
  4. (D) 16, 8, 16

Answer

(A) 16, 16, 32

#285 MCQ 1M 🖼 1

Question

Choose the correct option for the given symbol.

Options

  1. (A) Mating between relatives (consanguineous mating)
  2. (B) Parents above and children below (in order to birth-left to right)
  3. (C) Parents with male child affected with disease
  4. (D) 5 unaffected offsprings.

Answer

(C) Parents with male child affected with disease

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#286 CS

Question

Mendel worked on pea plant (1856-1863) and selected 14 true-breeding pea (Pisum sativum) plant varieties, as pairs which were similar except for one character with contrasting traits. Some of the contrasting traits selected were smooth or wrinkled seeds, yellow or green seeds, inflated (full) or constricted green or yellow pods and tall or dwarf plants.
Table

S.No.

Characters

Contrasting Traits

1.

Stem height

Tall / dwarf

2.

Flower colour

Violet / white

3.

Flower position

Axial / terminal

4.

Pod shape

Inflated / constricted

5.

Pod colour

Green / yellow

6.

Seed shape

Round / wrinkled

7.

Seed colour

Yellow /green
(i) How many pure line breed with contrasting traits is used by Mendel in his experiment?
(ii) For how many years, Mendel performed experiments on pea plant?
(iii) Which are the following traits are recessive taken by Mendel in his experiment? Dwarf plant, white flower, constricted pod, wrinkled seed, tall plant, yellow seed colour
(iv) Choose the dominant traits from the following.
(a) Dwarf plant (b) Wrinkled seed
(c) Constricted pod (d) Yellow seed colour
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#287 CS

Question

The effect of a gene on a single phenotype or trait. There are however instances where a single gene can exhibit multiple phenotypic expression. Such a gene is called a pleiotropic gene. The underlying mechanism of pleiotropy in most cases is the effect of a gene on metabolic pathways which contribute towards different phenotypes. An example, of this is the disease phenylketonuria, which occurs in humans. The disease is caused by mutation in the gene that codes for the enzyme phenylalanine hydroxylase (single gene mutation). This manifests itself through phenotypic expression characterised by mental retardation and a reduction in hair and skin pigmentation.
(i) What is pleiotropic gene?
(ii) What is the main cause of phenylketonuria?
(iii) What are the symptoms of phenylketonuria?
(iv) Give examples of pleiotropic disorders.
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#288 CS

Question

The sex determining mechanism in case of humans is XY type. Out of 23 pairs of chromosomes present, 22 pairs are exactly same in both males and females; these are the autosomes. A pair of X-chromosomes are present in the female, whereas, the presence of an X and Y chromosome are determinant of the male characteristic. In a number of other insects and mammals including man, XY type of sex determination is seen among the males an X-chromosome is present. Here male heterogamety and female homogamety is seen. But in some birds ZZ-ZW type of sex determination is seen where male is homozygous but female shows heterogamety.
(i) In which organisms XX-XY type of sex determination is present?
(ii) Which type of sex determination is seen in the grasshoppers?
(iii) What type of sex determination is seen in the hen?
(a) xx - xy (b) xx - xo
(c) zw - zz (d) AA - XX
(iv) How many percentage of sperms contain Y chromosome in a male?
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#289 CS 🖼 1

Question

The disease is controlled by a single pair of allele, HbA and HbS. Out of the three possible genotypes only homozygous individuals for HbS (HbS HbS) show the diseased phenotype. Heterozygous (HbA HbS) individuals appear apparently unaffected but they are carrier of the disease as there is 50 per cent probability of transmission of the mutant gene to the progeny.
(i) What happens due to mutation in the HbA gene in sickle cell anaemia?
(ii) Which type of mutation seen in the sickle cell anaemia?
(iii) What happens due to substitution of GAG with GUG?
(iv) What amino acids are present at the fifth and seventh position of HbA peptide?
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#290 CS

Question

Anirudh wanted to know the genotype of a pea plant in his kitchen garden that had violet flowers. To do this, he crossed the violet - flowered plant, with a white flowered plant, resulting in all plants with violet flowers. When these plants were self-pollinated, 75 violet - flowered plants and 22 white - flowered plants were produced. Now, he knows the genotype of the violet - flowered plant and can confirm it by crossing it with a white - flowered plant.
(i) Which Mendel's law is applied on above experiment ?
(a) Mendel's law of dominance
(b) Law of segregation
(c) Gamete purity law
(d) Law of incomplete dominance
(ii) What are the ratio of violet and white flower obtained in above experiment ?
(a) 1:1 (b) 9:3:3:1
(c) 3:1 (d) 1:2:1
(iii) According to the above experiment, when a plant with violet flowers was first crossed with a plant with white flowers, what percentage of the plants were found to have violet flowers ?
(a) 75 % (b) 25 %
(c) 20 % (d) 100 %
(iv) According to the above experiment, when a plant with violet flowers was first crossed with a plant with white flowers, what coloured flower was obtained in first generation ?
(a) Violet (b) Red
(c) White (d) Yellow
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#291 CS

Question

Mutation is a phenomenon which results in alteration of DNA sequences and consequently results in changes in the genotype and the phenotype of an organism. In addition to recombination, mutation is another phenomenon that leads variation in DNA. One DNA helix runs continuously from one end to the other in each chromatid, in a highly supercoiled form. Therefore loss (deletions) or gain (insertion/duplication) of a segment of DNA, result in alteration in chromosomes. Since genes are known to be located on chromosomes, alteration in chromosomes results in abnormalities or aberrations. Chromosomal aberrations are commonly observed in cancer cells.
(i) What is another phenomenon responsible for variation other than recombination?
(a) Translation (b) Transcription
(c) Mutation (d) Replication
(ii) What kind of changes are occured as a result of mutation ?
(a) genotype
(b) phenotype
(c) genotype and phenotype both
(d) Behaviour of organism
(iii) What are the reasons for alternation in chromosomes ?
(a) Deletion of DNA segment (gene)
(b) Insertion or duplication of DNA segment (gene)
(c) A and B both
(d) Unwinding of DNA helix only
(iv) Where chromosomal aberrations are seen generally ?
(a) Leucocytes (b) cancer cells
(c) Erythrocytes (d) Normal skin cell
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#292 CS 🖼 1

Question

The idea that disorders are inherited has been prevailing in the human society since long. This was based on the heritability of certain characteristic features in families. After the rediscovery of Mendel's work the practice of analysing inheritance pattern of traits in human beings began. Since it is evident that control crosses that can be performed in pea plant or some other organisms, are not possible in case of human beings, study of the family history about inheritance of particular trait provides an alternative. Such an analysis of traits in a several of generations of a family is called the pedigree analysis. In the pedigree analysis the inheritance of a particular trait is represented in the family tree over generations.
(i) The given symbol represents ________ for pedigree analysis.
(a) Affected individuals
(b) Mating
(c) Mating between relatives (consanguineous mating)
(d) Parents above and children below (in order of birth - left to right)
(ii) What is the method of analysis of a single trait in a human family for many generations called ?
(a) DNA fingerprinting (b) Gene mapping
(c) Pedigree analysis (d) Gene therapy
(iii) In which form, the analysis of traits are done in pedigree analysis ?
(a) As a family tree
(b) As a Punnett square
(c) As a bar graph
(d) Only as a mathematical equation
(iv) Which is the only option useful for understanding the heritability of a specific trait in humans ?
(a) DNA test of every person
(b) To create new organisms in the laboratory
(c) Studying the history of the family. (d) To imitate Mendel's pea experiments.

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