//M2//QN1//SUB//DL0

List the factors that affects our health.

//X

Our health is affected by the following:
(1) Genetic Disorder : A child is born with a defect and the effects of defects which the child inherits from parents from birth.
(2) Infections : Due to pathogens.
(3) Our way of life : Including the food we eat, the water we are drink, the rest and exercise we give the body, the habits we possess or lack.

//M2//QN2//SUB//DL0

What is health? Why is important to maintain good health?

//X

Health is not the 'absence of disease' or 'physical well-being' but health is being physically, mentally, emotionally and socially healthy. Health is increased life expectancy, as well as reduced infant and maternal mortality.
Importance of maintaing good health:
(1) When people are healthy, they can work more efficiently.
(2) A balanced diet, personal hygiene and regular exercises also, help to maintain good health is important.
(3) Yoga has also been practiced since ancient times to achieve physical and mental health.
(4) Awareness of diseases and their effects on various functions of the body , vaccination against communicable diseases, proper disposal of excreta, control of vectors and maintenance of hygienic food and water supply etc are essential for attaining good health.

//M2//QN3//SUB//DL0

What is a disease? In which groups are diseases classified? Explain with example.

//X

When the functions of one or more organs or systems of the body are adversely affected, due to which various reasons and signs or symptoms are observed. It is called a disease.
(Dis-not, ease i.e. not in ease)
Diseases are divided into groups like infectious and non-infectious or communicable or non-communicable.

(1) Contagious diseases : Diseases that can be transferred/spread easily from one person to another are called contagious diseases. Infectious diseases are common but some infectious diseases such as AIDS are fatal.

(2) Non-Contagious diseases : Diseases which can not be spread from one person to another are called non-contagious diseases e.g.

Cancer is a non-contagious disease, but it is a main reason of death.
Consumption of drugs and alcohol also adversely affects our health.

//M2//QN4//SN//DL0

Short note on : Typhoid

//X

Pathogen : Salmonella typhi
Spread through :
  • contaminated food and water
Signs/symptoms :

(1) Persistent high fever (39°C to 40°C)

(2) Weakness, abdominal pain, constipation, headache and loss of appetite.

(3) In severe cases intestinal perforation and sometimes death are possible.

Diagnosis : Widal test
Treatment : Antibiotics

//M2//QN5//SN//DL0//EQ//PYQ

Short note: Pneumonia

OR
Explain the disease and their symptoms caused by Haemophilus influenzae
(MARCH 2025, JULY 2023, May, 2021, March/April 2022)
OR
Describe symptoms and causative agent of pneumonia in human.

//X

Pathogen : Streptococcus pneumoniac and Haemophilus influenza
Spread through :
  • Droplets or aerosols released by an infected person through coughing or sneezing. Inhalation or by using the utensils of an infected person.
  • As a result of infection, the alveoli get filled with fluid leading to severe problem in respiration.
Symptoms :
  • Fever, chills, cough and headache
  • In severe condition, the lips and fingers become gray to blue in color.
Treatment : Antibiotics

//M2//QN6//SN//DL0

Write short note on Common cold

//X

Pathogen : Rhino virus and some other viruses.
Spreads through :

(1) Droplets resulting from cough and sneeze of an infected person are either inhalated direct by transmitted through pen, book, glass, door handle, computer keyboard or mouse etc.

(2) Rhino virus infects the nose and respiratory tract, but does not infect the lungs.

Symptoms :

(1) Nasal congestion and discharge, dry throat, runny nose, cough, headache, fatigue etc.

(2) These symptoms are observed for three to seven days.

//M3//QN7//SUB//DL0

Write in short about pathogen, spread of disease and symptoms of Ringworm

//X

(1) Pathogen : Fungi – like Microsporum, Trichophyton, Epidermophyton.
(2) Spread through :
This fungus is usually spread through soil or through the use of towels, clothes or combs of an infected person.

(3) Symptoms :

(1) It appears as dry, scaly lesions (ring like) on various parts of the body like skin, nails and scalp etc.
(2) Such lesions are intensely itchy.
(3) A warm and moist environment in areas such as folded skin, thighs and toes encourages the growth of fungus.

//M0//QN8//SUB//DL0//EQ

What are the various public health measures, which you would suggest as safeguard against infectious diseases?

//X

Health measures as a safeguard against infectious diseases. The public health measures that can be taken be avoid infectious are as follows :
(1) Immunisation drives : The populations should be vaccinated timely against infectious disease and properly so that they don't develop diseases.
(2) Awareness : Everybody should be educated or made aware of infectious diseases so that they can protect themselves from them.
(3) Cleanliness and sanitation : Public sanitation measures is good for avoiding infectious diseases. We should maintain cleanliness in our surroundings.
(4) Clean water supply : One should also maintain cleanliness and consume only clean drinking water and contamination-free fruits and vegetables.
(5) Eradication of vectors : The vectors of diseases must be eradicated by destroying the breeding sites of many vectors.

//M2//QN9//SUB//DL0

How does the study of biology help us to control infectious diseases? [NCERT Exercise Q.2]

//X

Various advancements in the field of biology give us insight into how to fight various infectious diseases.
With the knowledge of biology, the life cycle of parasites, pathogens and disease carriers can be studied and measures can be taken to control them.
Infectious diseases like small pox, measles, tuberculosis can be controlled by vaccination.
With the help of biotechnology, new effective and safe drugs, antibiotics and vaccines can be prepared.

//M3//QN10//SUB//DL0

What are pathogens? Elaborate and give examples.

//X

Many organisms like bacteria, viruses, fungi, parasites, worms are responsible for causing diseases in humans. Such disease causing organisms are called pathogens.
All parasites are pathogenic because they harm the host by staying in or on it. Pathogens enter our body throught many ways, multiply, disturb our essential functions.
As a result, external and functional disturbance occurs.
Pathogen has to adapt its life according to the internal environment of the host and also, resist to other factors. Such as.
Shows ability to survive in pH (< 7) and resist various digestive enzymes.
Examples :

Table

Disease

Pathogens

1

Typhoid

Salmonella typhi

2

Pneumonia

Streptococcus pneumoniae, Haemophilus influenzae

3

Common cold

Rhino virus

4

Malaria

Plasmodium species

5

Ascariasis

Ascaris lumbricoides

6

Elephantiasis/Filariasis

Wuchereria bancrofti

7

Ringworm

Microsporum, Trichophyton and Epidermophyton

//M2//QN11//SUB//DL0

What measures will you take to prevent the spread of water borne diseases?

[NCERT Exercise Q.4]

//X

Water borne diseases are :
Cholera, Typhoid, Amoebiasis, Ascariasis etc.
Measures to prevent spread :

(1) Reservoirs, pools, cess pools, tanks etc. should be periodically cleaned and kept clean.

(2) Purification of waste water through sewage plant.

(3) Chlorination of water and use it as drinking water.

//M2//QN12//SUB//DL0

What public awareness measures do you suggest to protect against communicable diseases?

OR
What are the measures should be taken for control of infectious / communicable diseases?

//X

Maintenance of personal and public hygiene is very important for prevention and control of many infectious diseases.
(1) Personal hygiene : Measures for personal hygiene include keeping the body clean; consumption of clean drinking water, food, vegetables, fruits, etc.
(2) Public hygiene : Public hygiene includes proper disposal of waste and excreta; periodic cleaning and disinfection of water reservoirs, pools, cesspools and tanks and observing standard practices of hygiene in public catering.
These measures are particularly essential where the infectious agents are transmitted through food and water such as typhoid, amoebiasis and ascariasis.

(3) Social distancing & Wearing mask : In cases of air-borne diseases such as pneumonia and common cold, in addition to the above measures, close contact with the infected persons or their belongings should be avoided.

For diseases such as malaria and filariasis that are transmitted through insect vectors, the most important measure is to control or eliminate the vectors and their breeding places.
This can be achieved by avoiding stagnation of water in and around residential areas, regular cleaning of household coolers, use of mosquito nets.
Introducing fishes like Gambusia in ponds that feed on mosquito larvae, spraying of insecticides in ditches, drainage areas and swamps, etc.

//M3//QN13//SUB//DL0//EQ

Give information about the diseases caused by worms in humans. OR Give the name and character of the disease caused by Entamoeba histolytica, Trichophyton and Wuchereria in human.

//X

Worm like Roundworm and Wuchereria like filariasis worm (elephantiasis worm) are pathogenic in humans.
1) Ascariasis :
Intestinal parasitic worms (Ascaris lumbricoids) cause this disease.
Spreads through :
  • The eggs of this parasite come out with the faeces of the infected person. It contaminates the soil, water and plants. Its infects a healthy person by consuming such contaminated severe cases of infection. (vegetables, fruits etc. causes)
Symptoms :
  • Internal bleeding, fever, anemia and intestinal obstruction.

2) Elephantiasis - Filariasis :

Pathogens : Wuchereria (W.bancrofti and W.malayi)
Spread through :
  • The pathogen are transmitted to a healthy person through the bite by female mosquito vector (Culex fatigans).
Symptoms :
  • These worms slowly developing chronic inflammation in the lymphatic vessels of a person and remain in the host for years, the leg below the knee gets swollen like the leg of an elephant, hence the disease is called elephantiasis.
  • Often the genitals are also affected by this disease, causing many deformities.

//M2//QN14//SUB//DL0

Explain : Amoebiasis.

//X

Amoebiasis (Amoebic dysentery) : Pathogen is Entamoeba histolytica.
Mode of transmission : Houseflies (carriers) transmit parasites from faeces to food and water.
Symptoms : Constipation, abdominal pain and cramps, stools with excess mucous and blood clots.

//M4//QN15//SUB//DL0//EQ//PYQ

Explain the life cycle of Plasmodium (with diagram).(JUNE 2025)

//X

(1) Plasmodium enters the human body in the form of sporozoites when an infected female Anopheles mosquito bites a human.
(2) Initially this parasite multiplies in the liver cells and then invades the blood cells causing RBC's to rupture.
(3) Rupture of RBC releases a toxic substance called Haemozoin, which causes chills and high fever for 3 to 4 days.
(4) At this stage, when a female Anopheles mosquito bites an infected person, the parasite enters the mosquito's body, where it develops further and multiply and form sporozoites.
(5) This sporozoite is stored in the salivary gland of the mosquito.
When this infected female mosquito bites a person, the parasite enters her body and develops.
Malaria parasite requires two hosts to complete its life cycle,
1) Human, 2) Mosquitoes.
Reproduction in Plasmodium
Asexual reproduction in humans :
(1) The parasite reproduces in the human RBC and destroys the RBC.
(2) In RBC the sexual stage (germ cells) develop male and female (male-microgametes, female-mega gamete).
These gametes enter mosquitoes from humans through mosquito bites.
Sexual reproduction in mosquito :
The Gametes entered into the mosquito from the human being are fertilized in the intestine of the mosquito and develop.
In order to develop, the sporozoite stage is stored in the salivary gland of the mosquito.
Malaria is a disease caused by Plasmodium.
Different species of Plasmodium (Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale) are responsible for different types of malaria.

//M2//QN16//SUB//DL0

What is active immunity?

//X

When a host is exposed to antigens, antibodies are produced in the host body.
Active immunity is slow.
It takes more time to give full effective response.
Injecting the microbes deliberately during immunisation or infectious organisms gaining access into body induces active immunity.
Antigens may be in the form of living or dead microbes or other proteins.

//M0//QN17//SUB//DL0//EQ

What does ‘a suitable gene’ means, in the context of DNA vaccine? Discuss.

//X

Recombinant DNA technology has allowed the production of antigenic polypeptides from the suitable gene which is a segment of DNA.
This DNA is cloned in to host cell, which now produce protein and used as vaccine.

//M0//QN18//SUB//DL0

Give the difference between Innate and Acquired Immunity.

//X

Innate Immunity

Acquired Immunity

1) Innate immunity includes all the defence elements with which an individual is born.

1) Acquired immunity responds to exposure to a pathogen, based on memory.

2) It consists of various types of barriers that prevent the entry of foreign agents.

2) Animals develop resistance in the body to fight diseases during their life.

//M0//QN19//SUB//DL0

Give the difference : Active immunity and passive immunity

//X

Active Immunity

Passive Immunity

1) When a host is exposed to antigens, which may be in the living or dead microbes or other proteins, antibodies are produced in the host body.

1) When ready-made antibodies are directly given to protect the body against foreign agents, it is called passive immunity.

2) It has long lasting effect.

2) It has short term
effect.

3) Active immunity is slow and takes time to give its full effective response.

3) Its effect is fast and gives immediate relief to the patient.

4) By injecting the microbes deliberately during immunisation active immunity can be achieved.

4) Example : IgA antibody in the colostrum of mother gives passive immunity to new born infant.

//M2//QN20//SUB//DL0

Explain autoimmunity.

//X

In higher lineages, memory-based acquired immunity is based on the ability to distinguish between self and non self (pathogens), which can be understood from two principles:
(i) Higher order lineages can differentiate into foreign cells as well as foreign organisms. Much of experimental immunology runs on this aspect.
(ii) Sometimes due to genetic or other unknown reasons, the body attacks its own cells, resulting in damage to the body, which is called an auto-immune disease.
Example :
Gout (rheumatoid arthritis).

//M2//QN21//SUB//DL0

State the types of acquired immunity.

//X

There are 2 types of acquired immunity :
1) Antibody mediated (B-cell based)
2) Cell Mediated Immunity (CMI) (T-cell based)

//M0//QN22//SUB//DL0

Describe primary lymphoid organ.

//X

Lymphoid organs: These are the organs where origin and/or maturation and proliferation of lymphocytes occur.
The primary lymphoid organs are bone marrow and thymus where immature lymphocytes differentiate into antigen-sensitive lymphocytes.
After maturation the lymphocytes migrate to secondary lymphoid organs like spleen.

(a) Bone marrow : The bone marrow is the main lymphoid organ where all blood cells including lymphocytes are produced.

(b) Thymus : The thymus is a lobed organ located near the heart and beneath the breastbone.

The thymus is quite large at the time of birth but keeps reducing in size with age and by the time puberty is attained it reduces to a very small size.
Both bone-marrow and thymus provide micro-environments for the development and maturation of T-lymphocytes.

//M0//QN23//SUB//DL0

Where are B-lymphocytes and T-lymphocytes formed? How do they differ from each other ?

//X

B-cells and T-cells both are lymphocytes and they are formed in bone marrow.
B-cells :

(1) They differentiate in bone marrow.

(2) They produce antibody (Protein) against antigen.

T-cells :

(1) They differentiate in thymus.

(2) T-lymphocytes help B-cells to produce antibody or killer T-cells which directly attack on antigen.

  • They are involved in Cell Mediated Immunity (CMI)

//M0//QN24//SUB//DL0

What is passive immunity ?

//X

When ready-made antibodies are directly given to protect the body against foreign agents, it is called passive immunity.
It has short term effect.
Its effect is fast and gives immediate relief to the patient.
Example : IgA antibody in the colostrum of mother gives passive immunity to new born infant.
The foetus also receives some antibodies from their mother, through the placenta during pregnancy.

//M0//QN25//SUB//DL0

Explain vaccination and immunization.

//X

The principle of immunisation or vaccination is based on the property of 'memory' of the immune system.
In vaccination, a preparation of antigenic proteins of pathogen or inactivated/weakened pathogen (vaccine) are introduced into the body.
The antibodies produced in the body against these antigens would neutralise the pathogenic agents during actual infection .
The vaccines also generate memory - B and T-cells that recognise the pathogen quickly on subsequent exposure and overwhelm the invaders with a massive production of antibodies.
If a person is infected with some deadly microbes to which quick immune response is required as in tetanus, we need to directly inject the preformed antibodies, or antitoxin (a preparation containing antibodies to the toxin).
Even in case of snakebites, the injection which is given to the patients, contains preformed antibodies against the snake venom. This type of immunisation is called passive immunisation.
Recombinant DNA technology has allowed the production of antigenic polypeptides of pathogens in bacteria or yeast.
Vaccines produced using this approach allow large scale production and hence greater availability for immunisation, e.g., hepatitis B vaccine produced from yeast.

//M2//QN26//SUB//DL0

What is allergy? Discuss in detail about it?

OR
Describe about the exaggerated response of immune system to certain antigen present in the environment

//X

An exaggerated response of the immune system to certain antigens present in the environment is called allergy.
Allergens : Substances causing allergy are called Allergens.
e.g. Dust mites, pollen, animal dung etc. are common examples of allergens.
Allergy Symptoms :
  • Sneezing, watery eyes, runny nose, difficulty in breathing etc.
  • Antibodies produced for allergy are of
    Ig-E type.
  • Allergies are caused by histamine and serotonin chemicals secreted from mast cells.
  • Allergy symptoms can be quickly reduced by medicines like antihistamines, adrenaline and steroids.
  • Nowadays, due to the modern lifestyle, immunity has decreased and sensitivity to allergens has increased.
  • In big cities of India mostly children are becoming victims of allergies and asthma due to their sensitivity towards the environment. The reason for this is to keep the child in a more secure family from the beginning.

//M3//QN27//SUB//DL0

Explain innate immunity in detail.

OR
Explain cellular barrier and cytokine barrier of innate immunity.

//X

Innate immunity is non-specific immunity, which is present at the time of birth.
1) Physical barrier:
Our skin is the main physical barrier that prevents the entry of microorganisms.
Mucous membrane lining the respiratory tract, gastrointestinal tract and urinary tract also helps to prevent germs from entering the body.
2) Physiological barrier:
Acid in the stomach, saliva in the mouth, tears in the eyes etc. inhibit the growth of pathogens.
3) Cellular Barrier:
Certain types of Leucocytes (WBC) of our body like polymorpho - nuclear leukocytes (PMNL - neutrophils) and monocytes and natural killer (type of lymphocytes) in the blood as well as macrophages in tissues can phagocytise and destroy microbes.
4) Cytokine barrier:
Virus-infected cells secrete proteins called interferons, which protect other uninfected cells from virus infection.

//M0//QN28//SUB//DL0

Give names of Primary and Secondary lymphoid organs.

//X

(1) Primary lymphoid organs - Bone marrow and Thymus.
(2) Secondary lymphoid organs - spleen, lymph nodes, tonsils, Peyer's patches of small intestine and appendix.

//M3//QN29//SUB//DL0

Give information about primary and secondary lymphoid organ.

OR
Explain lymphatic organs of human lymphatic system. (Diagram is not required)

//X

These are the organs where origin/maturation and proliferation of lymphocytes occur. These are of two types : Primary and Secondary.
(a) Primary lymphoid organs
  • The organs where lymphocytes are matured and differentiated to antigen-sensitive lymphocytes. It is of two types :
1) Bone marrow :
  • The site of formation of all blood cells including B and T-lymphocytes.
2) Thymus :
  • A bilobed organ seen near the heart and beneath the breastbone. It is large during birth but gradually reduces in size and becomes very small-sized in puberty. Immature T-lymphocytes from bone marrow is migrated to thymus and matured.
(b) Secondary lymphoid organs
  • The organs, to which matured lymphocytes migrate from primary lymphoid organs, interact with antigens and then proliferate to become effector cells.
  • The secondary lymphoid organs provide the sites for interaction of lymphocytes with the antigen, which then proliferate to become effector cells.
  • E.g. Spleen, lymph nodes, tonsils, Peyer's patches, Mucosa- associated lymphoid tissue (MALT) and appendix.
Spleen :
  • Bean-shaped organ. Contains lymphocytes and phagocytes → It removes worn-out RBCs and microorganisms from blood → It is a reservoir of erythrocytes in foetus.
Lymph nodes :
  • Found in lymphatic system → They trap microorganisms or other antigens → Trapped antigens activate lymphocytes and cause immune response.
MALT :
  • Located within the lining of respiratory, digestive and urinogenital tracts called mucosa associated lymphoid tissue. It constitutes 50% of lymphoid tissue.

//M4//QN30//SUB//DL0//EQ

Describe : Acquired Immunity.

OR
Explain molecular structure of antibody with diagram.[NCERT Exercise Q.9]
OR
Draw a well labelled diagram for H2L2.

//X

The body is able to defend itself from most of these foreign agents.
This over all ability of the host to fight the diseases-causing organisms, conferred by the immune system is called immunity.
Immunity is of two types :
  • Innate immunity
  • Acquired immunity
Acquired immunity is pathogen specific. It is characterised by memory.
This means that our body, when encounters a pathogen for the first time, produces a response called primary response which is of low intensity.
Subsequent encounter with the same pathogen elicits a highly intensified secondary or anamnestic response.
The primary and secondary immune responses are carried out with the help of two special types of lymphocytes present in our blood,
i.e., B-lymphocytes and T- lymphocytes.
There are two type of acquired immune response.

(i) Antibody Mediated Immune response or / Humoral Immune response.

The B-lymphocytes produce an army of proteins in response to pathogens into our blood to fight with them. These proteins are called antibodies.
The T-cells themselves do not secrete antibodies but help B cells produce them.
Each antibody molecule has four peptide chains, two small called light chains and two longer, called heavy chains.
Hence, an antibody is represented as H2L2. Different types of antibodies are produced in our body.
IgA, IgM, IgE, IgG are some of them. Because these antibodies are found in the blood, the response is also called humoral immune response.

(ii) Cell Mediated Immune response

The second type is called cell-mediated immune response or cell- mediated immunity (CMI).
The T-lymphocytes mediate CMI.
Tissue matching, blood group matching are essential before undertaking any graft / transplant and even after this the patient has to take immuno suppresants all his life.
The body is able to differentiate ‘self’ and ‘non self’ and the CMI is responsible for graft rejection.

//M2//QN31//SUB//DL0

State the diagnosis and treatment of AIDS.

//X

Diagnosis
Diagnostic test for AIDS- Enzyme Linked Immuno-Sorbent Assay (ELISA).
Treatment of AIDS
  • Treatment of AIDS with anti-retroviral drugs- partially effective
  • Drugs can only prolong the life of the patient but can not prevent death, which is inevitable.

//M2//QN32//SUB//DL0

Give the full name of the following.

//X

MALT : Mucosa Associated Lymphoid Tissue
AIDS : Acquired Immuno Deficiency Syndrome
CMI : Cell Mediated Immunity
NACO : National AIDS Control Organization
HIV : Human Immunodeficiency Virus

//M2//QN33//SUB//DL0

Mention the mode of transmission of HIV.

OR
What are the various routes by which transmission of human immunodeficiency virus takes place?

//X

Modes of Transmission of HIV infection :
(a) sexual contact with infected person.
(b) transfusion of contaminated blood and blood products
(c) sharing infected needles as in the case of intravenous drugs abusers
(d) from infected mother to her child through placenta.

//M2//QN34//SUB//DL0

State the symptoms of AIDS.

//X

There are three stages of HIV infections.
(1) The asymptomatic HIV infections :
In this, person looks healthy, HIV symptoms are not appeared but a person act as a carrier of the HIV.
(2) Acute HIV infections :
It is the earliest stage of HIV infection, and it generally develops within 2 to 4 weeks.
During this time, some people have flu-like symptoms, such as fever, headache, rash, blood in the stool, loss of appetite and weight loss.
This is called AIDS related complex (ARC)
ARC developes into chronic disease (AIDS)
(3) AIDS :
This is last stage of AIDS and following symptoms appeared.
Rapid weight loss up to 10 percent without any reason.
Recurring fever for more than one month.
Common cold cough, pneumonia etc.
Prolonged swelling of the lymph glands.
Skin cancer

//M3//QN35//SUB//DL0//EQ//PYQ

With the help of labelled diagram, show replication of retrovirus.

(MARCH 2024) (JULY 2023)
OR What is the mechanism by which the AIDS virus causes deficiency of immune system of the infected person?

//X

Mechanism of action/replication of HIV :
1) HIV (Human Immunodeficiency virus)
is a RNA virus
  • After getting into the body of the person, the virus enters into macrophages where RNA genome of the virus replicates to form viral DNA with the help of the enzyme reverse transcriptase.
  • This viral DNA gets incorporated into host cell’s DNA and directs the infected cells to produce virus particles.
  • The macrophages continue to produce virus and in this way acts like a HIV factory.
  • Simultaneously, HIV enters into helper T-lymphocytes (TH), replicates and produce progeny viruses. The progeny viruses released in the blood attack other helper T-lymphocytes.
  • This is repeated leading to a progressive decrease in the number of helper T-lymphocytes in the body of the infected person.
  • During this period, the person suffers from bouts of fever, diarrhoea and weight loss. Due to decrease in the number of helper T lymphocytes, the person starts suffering from infections that could have been otherwise, overcome such as those due to bacteria especially Mycobacterium, viruses, fungi and even parasites like Toxoplasma. The patient becomes so immuno-deficient that he/she is unable to protect himself/herself against these infections.

//M2//QN36//SUB//DL0

State the measures to prevent AIDS.

OR
Explain prevention of AIDS.

//X

AIDS can not be cured, caution is the best option.
(1) HIV infection which includes making blood (from blood banks) safe.
(2) From HIV, ensuring the use of only disposable needles and syringes in public and private hospitals and clinics
(3) Free distribution of condoms
(4) Controlling drug abuse
(5) Advocating safe sex and promoting regular
check-ups for HIV in susceptible populations.

//M0//QN37//SUB//DL0

How do cancer cells differ from normal cells?

//X

Cell growth and differentiation is highly controlled and regulated which is lacking in cancerous cells
Normal cell shows a property of contact inhibition which inhibits uncontrolled growth
Cancer cells appear to have lost this property. As a result of this, cancerous cells just continue to divide giving rise to masses of cells called tumors.

//M3//QN38//SUB//DL0

What is meant by metastasis?

OR
Give difference between Benign and Malignant cancer and explain the agents responsible for transformation of normal cells into cancerous cells.(AUGUST 2020)
OR
Describe the causative agents of cancer; Explain different diagnosis method of cancer.(MARCH 2025)

//X

Cancerous cells continue to divide giving rise to mass of cells called tumours.
There are two types of tumours :
(1) Benign tumour:
(2) Malignant tumour:
(1) Benign tumour:
Confined to the place of its origin. They do not spread to other parts. Cause little damage.
(2) Malignant tumour:
Mass of proliferating cells (neoplastic or tumour cells) that grow rapidly, invade and damage the surrounding normal tissues.
Due to active division and growth, they starve normal cells by competing for nutrients.
Cells sloughed from tumors reach other sites via blood where they form a new tumour. This is called metastasis.

//M2//QN39//SUB//DL0

State the causes of cancer.

//X

Causes of Cancer :
Normal cells transformed into cancerous neoplastic cells by physical, chemical and biological agents.
These agents are called carcinogens.

(1) Physical agents: Ionizing radiation like X-rays, gamma rays, non-ionizing radiations like UV-rays.

(2) The chemical carcinogens: present in tobacco smoke have been identified as a major cause of lung cancer.

(3) Biological agents :

  • Cancer causing viruses called oncogenic viruses have a gene called viral oncogenes, induce transformation of neoplastic cells.
  • Cellular oncogenes (c-onc) or proto oncogenes in normal cells, when activated lead to oncogenic transformation of the normal cells.

//M2//QN40//SUB//DL0

Explain detection and diagnosis of cancer.

//X

Detection of Cancer :
(1) Biopsy and histopathological study
  • Tissue and blood and bone marrow tests for increased cell counts (leukemias);
  • Biopsy of a piece of the suspected tissue cut into thin sections is stained and examined under microscope (histopathological studies) by a pathologist.
(2) Radiography like X-rays, CT (computerized tomography)
  • Techniques like radiography (use of x-rays), CT (computed tomography) and MRI (Magnetic resonance detect cancers of the internal organs).
  • CT Scan : Computed tomography uses X-rays to generate a three-dimensional image of the internals of an object. Used to detect cancers of the internal organs.

MRI (magnetic resonance imaging) :

  • Uses strong magnetic fields and non-ionizing radiations to accurately detect pathological and physiological changes in the living tissue.
(3) Molecular diagnostic technique :
  • Antibodies against cancer-specific antigens are also used for detection of certain cancers.
  • Techniques of molecular biology can be applied to detect genes in individuals with inherited susceptibility to certain cancers.
  • Identification of such genes, which predispose an individual to certain cancers, may be very helpful in prevention of cancers.
  • Such individuals may be advised to avoid exposure to particular carcinogens to which they are susceptible (e.g., tobacco smoke in case of lung cancer).

//M2//QN41//SUB//DL0//PYQ

Write about diagnosis and treatment of Cancer.

(MARCH 2025, JUNE 2024)

//X

Surgery, radiation therapy and immunotherapy are commonly used to treat cancer.
(1) In radiation therapy, the tumour is treated with lethal radiation, but care is taken not to injure the surrounding normal cells.
(2) Some chemotherapy drugs (chemotherapeutic drugs) are used to kill cancer cells. Some of these drugs are specific for specific tumours.
Most medicines have side effects like hair loss, anaemia etc.

(3) Most cancers are treated by combination of surgery, radiotherapy and chemotherapy.

(4) Immunotherapy - involves use of biological response modifier like α-interferon which activates immune system to detect the cancer cells and destroy them.

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Draw the chemical structure of a molecule of morphine and cannabinoids.

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Chemical structure of morphine : (C17H19NO3) molecule
Chemical structure of the molecule Cannabinoids: (C21H30O2)

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Give your comment on Opioids.

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Refer diagram A from Q.42
(1) Opioids are the drugs, which bind to specific opioid receptors present in our central nervous system and gastrointestinal tract.
(2) Heroin commonly called smack is chemically diacetylmorphine which is a white, odourless, bitter crystalline compound.
(3) This is obtained by acetylation of morphine which is extracted from the latex of poppy plant Papaver somniferum.
(4) Generally, it is taken by snorting and injections, heroin is a depressant and slows down body functions.

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Give information about Cannabinoids.

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Refer diagram B from Q.42
Cannabinoids are a group of chemicals which interact with cannabinoid receptors present principally in the brain.
Natural cannabinoids are obtained from the inflorescences of the plant Cannabis sativa.
The flower tops, leaves and the resin of cannabis
plant are used in various combinations to produce marijuana, hashish, charas and ganja.
Generally taken by inhalation and oral ingestion, these are known for their effects on cardiovascular system of the body.

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Write in brief about cocaine drug.

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Coca alkaloid or cocaine is obtained from coca plant Erythroxylum coca, native to South America.
It interferes with the transport of the neuro-transmitter dopamine.
Cocaine, commonly called coke or crack is usually snorted.
It has a potent stimulating action on central nervous system, producing a sense of strong feeling of happiness (euphoria) and increased energy.
Excessive dosage of cocaine causes hallucinations.
Other well-known plants with hallucinogenic properties are Atropa belladona and Datura
These days cannabinoids are also being abused by some sportspersons, actors/celebrates etc.

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Mention the effects of smoking on human health.

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It contains alkaloid nicotine which is a stimulant and toxin.
(1) Nicotine stimulates adrenal gland to release adrenaline and nor-adrenaline which increases blood pressure and heart rate.
(2) Smoking of tobacco increases chances of lung cancer, bronchitis, emphysema, coronary heart diseases, cancer of throat, gastric ulcer, cancer of urinary bladder etc.
(3) Smoking of tobacco also increases carbon monoxide content of blood and reduces concentration of haem-bound oxygen which causes oxygen deficiency in the body.

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Why is that once a person starts taking alcohol or drugs, it is difficult to get rid of this habit? Discuss it with your teacher.

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Consumption of alcohol or drugs is intuitively addictive in nature, it increases and provides temporary strong feeling of happiness euphoria.
Repeated use of drugs increases the tolerance level of the receptors present in our body leads to higher doses of drugs and alcohol leading to greater intake and addiction.

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Do you think that friends can influence one to take alcohol/drugs? If yes, how may one protect himself/herself from such an influence?

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Yes, friends can influence one to take drugs. Following measures can be taken to prevent :
(i) Avoiding measures peer pressure.
(ii) Not taking undue pressure of failures beyond its threshold.
(iii) Getting counselling from a counsellor
(iv) Seeking help from parents and peers
(v) Seeking medical help.

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Discuss the important measures that are useful in preventing and controlling the use of alcohol and drugs in youth.

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(i) Avoid undue peer pressure :
(a) Every child has his/her own choice and personality, which should be respected and nurtured.
(b) A child should not be pushed unduly to perform beyond his/her threshold limits; be it studies, sports or other activities.
(ii) Education and counseling :
(a) Educating and counseling him/her to face problems and stresses and to accept disappointments and failures as a part of life.
(b) It would also be worthwhile to channelise the child's energy into healthy pursuits like sports, reading, music, yoga and other extracurricular activities.
(iii) Seeking help from parents and peers :
(a) Help from parents and peers should be sought immediately, so that, they can guide appropriately.
(b) Help may even be sought from close and trusted friends. Besides, getting proper advice to sort out their problems, this would help youth to vent their feelings of anxiety and guilt.
(iv) Looking for danger signs :
(a) Alert parents and teachers need to look for and identify the danger signs discussed above.
(b) Even friends, if they find someone using drugs or alcohol, should not hesitate to bring this to the notice of parents or teachers in the best interests of the person concerned.
(c) Appropriate measures would then be required to diagnose the malady and the underlying causes.
This would help in initiating proper remedial steps or treatment.
(v) Seeking professional and medical help :
(a) A lot of help is available in the form of highly qualified psychologists, psychiatrists, and de-addiction and rehabilitation programs to help individuals who have unfortunately got into quagmire of drug/alcohol abuse.
(b) With such help, the affected individual with sufficient efforts and will power, can get rid of the problem completely and lead a perfectly normal and healthy life.
Q.50.Explain that adolescence is a very sensitive phase of a person's mental and scientific development.
Ans. The period between 12-18 years of age may be thought of as adolescence period.
Adolescence is a bridge linking childhood and adulthood.
It is accompanied by several biological and behavioural changes.
Thus, it is a very vulnerable phase of mental and psychological development of an individual.
The first use of drugs or alcohol may be out of curiosity or experimentation.
The problem becomes more complicated with the initiation of consumption of such substances.
Some, teenagers use it to escape from problems.
Of late, stress, from pressures to excel in academics or examinations, has played a significant role in persuading the youngsters to try alcohol and drugs.
The perception among youth that it is 'cool' or progressive to smoke, use drugs or alcohol, is also in a way a major cause for youth to start these habits.
At puberty, a person feels a pressure to create an identity.
Television, movies, newspapers, internet also help to promote this perception.
Family instability or lack of mutual support is also a cause of psychological stress.
Q.51.Explain addiction and dependence in your words.
Ans. Because of the perceived benefits, drugs are frequently used repeatedly.
The most important thing, which one fails to realise, is the inherent addictive nature of alcohol and drugs.
Addiction is a psychological attachment to certain effects –such as euphoria and a temporary feeling of well-being associated with drugs and alcohol.
These drive people to take them even when these are not needed, or even when their use becomes self-destructive.
With repeated use of drugs, the tolerance level of the receptors present in our body increases.
Consequently the receptors respond only to higher doses of drugs or alcohol leading to greater intake and addiction.
However, it should be clearly borne in mind that use of these drugs even once, can be a fore-runner to addiction.
Thus, the addictive potential of drugs and alcohol, pull the user into a vicious circle leading to their regular use (abuse) from which he/she may not be able to get out.
In the absence of any guidance or counselling, the person gets addicted and becomes dependent on their use.
Dependence is the tendency of the body to manifest a characteristic and unpleasant withdrawal syndrome if regular dose of drugs/alcohol is abruptly discontinued.
This is characterised by anxiety, shakiness, nausea and sweating, which may be relieved when use is resumed again.
In some cases, withdrawal symptoms can be severe and even life threatening and the person may need medical supervision.
Dependence leads the patient to ignore all social norms in order to get sufficient funds to satiate his/her needs. These result in many social adjustment problems.
Q.52.List the harmful effects caused by drug/alcohol abuse.
OR
Describe any four effects of alcohol and drug abuse.
Ans. The immediate adverse effects of drugs and alcohol abuse are manifested in the form of reckless behaviour, vandalism and violence.
Excessive doses of drugs may lead to coma and death due to respiratory failure, heart failure or cerebral hemorrhage.
A combination of drugs or their intake along with alcohol generally, results in overdosing and even deaths.
The most common warning signs of drug and alcohol abuse among youth include drop in academic performance, unexplained absence from school/college, lack of interest in personal hygiene, withdrawal, isolation, depression, fatigue, aggressive and rebellious behaviour, deteriorating relationships with family and friends, loss of interest in hobbies, change in sleeping and eating habits, fluctuations in weight, appetite, etc.
Those who take drugs intravenously (direct injection into the vein using a needle and syringe), are much more likely to acquire serious infections like AIDS and Hepatitis B.
The chronic use of drugs and alcohol damages nervous system and liver (cirrhosis).
The use of drugs and alcohol during pregnancy is also known to adversely affect the foetus.
Another misuse of drugs is what certain sportspersons do to enhance their performance.
They (mis)use narcotic analgesics, anabolic steroids, diuretics and certain hormones in sports to increase muscle strength and bulk and to promote aggressiveness and as a result increase athletic performance.
The side-effects of the use of anabolic steroids in females include masculinisation (features like males), increased aggressiveness, mood swings, depression, abnormal menstrual cycles, excessive hair growth on the face and body, enlargement of clitoris, deepening of voice.
In males it includes acne, increased aggressiveness, mood swings, depression, reduction of size of the testicles, decreased sperm production, potential for kidney and liver dysfunction, breast enlargement, premature baldness, enlargement of the prostate gland.
These effects may be permanent with prolonged use. In the adolescent male or female, severe facial and body acne, and premature closure of the growth centres of the long bones may result in stunted growth.
Q.53.What is withdrawal syndrome? Describe its Symptoms.
OR
Write about withdrawal syndrome.
Ans. Dependency is the tendency of the body to manifest a characteristic and unpleasant withdrawal syndrome if regular dose of drug / alcohol is abrupty discontinued. This is characterised by anxiety, shakiness, nausea and sweating etc.