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Causes of diseases:
Health does not simply mean ‘absence of disease’ or ‘physical fitness’. It could be defined as a state of complete physical, mental and social well-being. Typhoid and pneumonia is caused by bacteria while AIDS, common cold, dengue and chikungunya are caused by virus. Plasmodium and Amoeba causes malaria and amoebiasis. Microsporum, Trichophyton and Epidermophyton are responsible for ringworms. Aedes mosquitoes is a vector for diseases like dengue and chikungunya , filariasis is spread by Culex mosquitoes. 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. Vaccinations are also done for certain diseases.
(i) What are the diseases caused by bacteria?
(ii) Name the mosquito vectors for malaria, elephantiasis and dengue?
(iii) What is health?
(iv) Give the names of pathogenic protozoans and disease caused by them.
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(i) Typhoid - Salmonella typhi
Pneumonia - Streptococcus pneumoniae
(ii) Malaria - female Anopheles mosquito
Elephantiasis - culex mosquito
Dengue - Aedes mosquito
(iii) Health could be defined as a state of complete physical, mental and social well-being
(iv) Plasmodium falciparum - Malaria
Entamoeba histolytica - Amoebiasis
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Antibodies:
There are two special types of lymphocytes present in our blood, i.e., B-lymphocytes and T-lymphocytes. 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 to produce them. Each antibody molecule has four peptide chains, two small chains 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 as humoral immune response. This is one of the two types of acquired immune response, first antibody mediated. The second type is called cell-mediated immune response or cell-mediated immunity (CMI).
(i) Which type of immunity is provided by B and T lymphocytes?
(ii) How many polypeptide chains are present in the molecule of antibody?
(iii) Rahul has undergone an organ transplant but the organ is rejected in his body. Which immunity is responsible for this response?
(iv) Where does B and T lymphocyte generated?
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(i) B-cell : Antibody mediated immunity
T-cell : Cell mediated immunity
(ii) Total four chains : 2 light and 2 heavy (H2L2) chains
(iii) Cell mediated immunity (CMI)
(iv) Bone marrow
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Adversity of tobacco on human health.
Smoking also paves the way to hard drugs. Tobacco has been used by human beings for more than 400 years. It is smoked, chewed or used as a snuff. Tobacco contains a large number of chemical substances including nicotine, an alkaloid. Nicotine stimulates adrenal gland to release adrenaline and nor-adrenaline into blood circulation, both of which raise blood pressure and increase heart rate. Smoking is associated with increased incidence of cancers of lung, urinary bladder and throat, bronchitis, emphysema, coronary heart disease, gastric ulcer, etc. Tobacco chewing is associated with increased risk of cancer of the oral cavity. Smoking increases carbon monoxide (CO) content in blood and reduces the concentration of haembound oxygen. This causes oxygen deficiency in the body.
(i) What happens due to increased level of CO in the blood?
(ii) How does tobacco consumption affect on
health?(iii) Describe side effects of smoking.(iv) Tobacco contains_____ chemical compound.
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(i) Smoking increases carbon monoxide (CO) content in blood and reduces the concentration of haembound oxygen. This cause oxygen deficiency in the body.
(ii) Tobacco contains a large number of chemical substances including nicotine, an alkaloid, Nicotine present in tobacco stimulates adrenal gland to release adrenaline and nor-adrenaline in to blood circulation, both of which raise blood pressure and increase heart rate.
(iii) Smoking is associated with increased incidence Oral cancers of lung, urinary bladder and throat, bronchitis, emphysema, coronary heart disease, gastric ulcer etc. Tobacco chewing is associated with increased risk of cancer of oral cavity.
(iv) Alkaloid nicotine
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Immunity:
Memory-based acquired immunity evolved in higher vertebrates based on the ability to differentiate foreign organisms (e.g., pathogens) from self-cells. While we still do not understand the basis of this, two corollaries of this ability have to be understood. One, higher vertebrates can distinguish foreign molecules as well as foreign organisms. Most of the experimental immunology deals with this aspect. Two, sometimes, due to genetic and other unknown reasons, the body attacks self-cells. This results in damage to the body and is called auto-immune disease. Rheumatoid arthritis which affects many people in our society is an auto-immune disease.
(i) What are the basis of acquired immunity in higher vertebrates?
(ii) Describe reasons for auto immune disease.
(iii) Give any two examples of auto immune diseases.
(iv) Which auto immune disease is caused by deficiency of insulin?
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(i) Memory-based acquired immunity evolved in higher vertebrates based on the ability to differentiate foreign organisms from self-cells.
(ii) Higher vertebrates can distinguish foreign molecules as well as foreign organisms but due to genetic and other unknown reasons, the body attacks self-cells. This results in damage to the body and is called auto-immune disease.
(iii) Rheumatoid arthritis
Myasthenia gravis
(iv) IDDM (Insulin Dependent Diabetes Mellitus)
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A 25-year-old patient has been admitted to the hospital with intermittent episodes of high fever for the past week. He experiences unbearable chills with shivering before the fever sets in, and this cycle repeats itself every 48 to 72 hours. Blood tests reveal that parasites are asexually reproducing in his red blood cells (RBCs). When these cells rupture, a toxic substance called hemozoin is released, which is responsible for fever. According to the patient's report, he has contracted the most severe form of malaria which can be fatal.
The doctor explained that the female Anopheles mosquito is responsible for the spread of this disease, which introduces the parasite into the human body in an infectious state.
(i) Which of the following events is directly responsible for the repeated cycles of severe fever and chills seen in the patient ?
(a) Multiplication of sporozoites in liver cells.
(b) Rupture of blood cells and release of hemozoin
(c) Fertilisation and development in the gut of the mosquito
(d) Development of germ cells in red blood cells.
(ii) If this patient is infected by
P. falciparum, how does it differ from other plasmodium species ?
(a) It damages only liver cells.
(b) It is known to cause the most severe and deadly malaria.
(c) It does not require a mosquito in its life cycle.
(d) None of the above.
(iii) Which statement is true regarding the requirement of two hosts to complete the life cycle of plasmodium ? (a) The sexual stage occurs in humans and the asexual stage occurs in mosquitoes.
(b) Both stages (sexual and asexual) are completed only in humans.
(c) The asexual stage occurs in humans and the sexual stage occurs in mosquitoes.
(d) Only sexual reproduction occurs in both humans and mosquitoes.
(iv) Due to prolonged infection, which organ of the patient may experience enlargement ? (a) Thymus (b) Spleen
(c) Appendix (d) Prostate gland
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(i) (b) Rupture of blood cells and release of hemozoin
(ii) (b) It is known to cause the most severe and deadly malaria.
(iii) (c) The asexual stage occurs in humans and the sexual stage occurs in mosquitoes.
(iv) (b) spleen
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When our body encounters a pathogen for the first time it produces a slow and low intensity response. This is called primary response. But when it encounters with the same pathogen elicits a highly intensified secondary or anamnestic response. All these response are based on B and T lymphocytes. B-lymphocytes produce protein army known as antibodies. These antibodies have a specific structure and are of different types. Some antibodies are passed on to the child from the mother. If this system is disrupted, the body can damage its own cells.
(i) What is the main reason for the high intensity of anamnestic response?
(a) It is a part of Innate immunity.
(b) It is based on memory characteristic of immune system
(c) It is possible through passive immunity
(d) It does not require antibody.
(ii) Which antibody an infant get from a mother's milk (colostrum) and which type of immunity is it ?
(a) IgE, Active immunity
(b) IgG, Cellular immunity
(c) IgA, Passive immunity
(d) IgM, Innate immunity
(iii) Which statement is correct regarding structure and function of antibody ?
(a) It has H4L4 structure.
(b) It has antigen binding site, which forms antigen-antibody complex.
(c) It only present in digestive track.
(d) It is not an army of protein but lipid.
(iv) If a person's immune system fails to distinguish between 'self' and 'non-self' and destroys its own cells, what disease can it cause ?
(a) Ascariasis
(b) Rheumatoid Arthritis
(c) Typhoid
(d) Elephantiasis
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(i) (b) It is based on memory characteristic of immune system.
(ii) (c) IgA , Passive immunity
(iii) (b) It has antigen binding site, which forms antigen - antibody complex.
(iv) (b) Rheumatoid Arthritis
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A person has a persistent decrease in the number of helper T-lymphocytes in his blood. In the examination, it is found that they are infected with HIV, a retrovirus. After HIV enters the body, it enters macrophage cells, DNA from new viruses and its own RNA. This viral DNA incorporates into host genome and new viruses are produced. As a result, the patient's immune system becomes so weak that he finds even common bacterial (such as mycobacterium) and fatal fungal infections. According to the doctor, there can be a period of 5 to 10 years between infection and the appearance of symptoms.
(i) Why macrophages are called 'factories of HIV' ?
(a) Because, lymphocytes are synthesised in it.
(b) Because, HIV replicates and produce new viral molecules in it.
(c) Because, blood gets purified there.
(d) Because, It produces antibody.
(ii) Which enzyme helps in the production of viral DNA from viral RNA during the reproduction cycle of HIV ?
(a) Ligase
(b) Helicase
(c) Reverse transcriptase
(d) Protease
(iii) Due to the decrease in the number of which cells in an AIDS patient, he becomes a victim of serious opportunistic infections ?
(a) RBCs
(b) Natural Killer T-cells
(c) Helper T-lymphocytes
(d) Platelets
(iv) Which of the following beliefs about the spread of HIV is incorrect (i.e. HIV does not spread)?
(a) From sexual intercourse with a infected person.
(b) Only by physical touch and contact
(c) By using contaminated blood
(d) Infant from infected mother
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(i) (b) Because, HIV replicates and produce new viral molecules in it.
(ii) (c) Reverse transcriptase
(iii) (c) Helper T-lymphocytes
(iv) (b) Only by physical touch and contact
