Free Biodiversity and Variety of Life MCQs with Answers

51. Antibodies in our body are complex :

• A. Glycoproteins
• B. Lipoproteins
• C. Steroids
• D. Prostaglandins

Explanation: Antibodies are members of a class of proteins known as immunoglobulins. Immunoglobulins are glycoproteins in the immunoglobulin superfamily. The terms antibody and immunoglobulin are often used interchangeably. They are found in the blood and tissue fluids, as well as many secretions. In structure, they are globulins (in the region of protein electrophoresis). They are synthesized and secreted by plasma cells that are derived from the B cells of the immune system.

52. Which one of the following depresses brain activity and produces feelings of calmness, relaxation, and drowsiness?

• A. Morphine
• B. Valium
• C. Amphetamines
• D. Hashish

Explanation: Valium is a benzodiazepine (sedative) that gives a feeling of relaxation, calmness, or drowsiness in the body. Morphine is the main opium alkaloid that depresses the respiratory center and contributes to the fall in blood pressure. Amphetamines are synthetic drugs and are stimulant in nature. Hashish is a hallucinogen.

53. Damage to thymus in a child may lead to :

• A. A reduction in haemoglobin content of blood
• B. A reduction in stem cell production
• C. Loss of antibody mediated immunity
• D. Loss of cell mediated immunity.

Explanation: The thymus is the major gland of our immune system. It is responsible for numerous immune system functions, including the production of T-lymphocytes, a type of white blood cell responsible for cell-mediated immunity. Cell-mediated immunity is a type of defense in which specialized cells carry out protective activities, safeguarding the body against pathogens, including protists and fungi that have entered the host's cells. T-cells and B-cells are the types of lymphocytes that develop from bone marrow cells. Those lymphocytes that migrate to the thymus and differentiate are called T-cells, while those cells that continue to differentiate in the bone marrow are known as B-cells. T-cells are responsible for cell-mediated immunity, whereas B-cells produce antibodies and participate in antibody-mediated immunity.

54. Which one of the following is not correctly matched?

• A. Glossina Palpalis; Sleeping Sickness
• B. Culex Pipiens; Filariasis
• C. Aedes Aegypti; Dengue Fever
• D. Anopheles Culifacies; Leishmaniasis

Explanation: All the options given are diseases with their associated vectors that transmit the respective diseases. Leishmaniasis, also called kala azar, is caused by Leishmania donovani. It is spread by the sand fly (Phlebotomus) and is characterized by an enlarged spleen and liver, along with high fever. Sleeping sickness is caused by the protozoan Trypanosoma gambiense. Filariasis is caused by the worm Wuchereria bancrofti. Dengue fever is caused by an arbovirus.

55. Carcinoma refers to :

• A. Malignant tumours of the connective tissue
• B. Malignant tumours of the skin or mucous membrane
• C. Malignant tumours of the colon
• D. Benign tumours of the connective tissue.

Explanation: Carcinoma is a type of cancer that arises in the epithelium, which is the tissue that lines the skin and internal organs of the body. It may occur in any tissue containing epithelial cells. This category includes cervical cancer, breast cancer, skin cancer, stomach cancer, and others.

56. Christmas disease is another name for :

• A. Haemophilia-B
• B. Hepatitis-B
• C. Down's syndrome
• D. Sleeping sickness.

Explanation: Haemophilia B, a type of haemophilia, is also known as Christmas disease. It is due to a deficiency of a blood coagulation factor known as the Christmas factor (Factor IX). Christmas was the individual (20th century) in whom the factor was first identified. Haemophilia B is a blood disorder that prevents it from clotting.

57. Salmonella is related with :

• A. Typhoid
• B. Polio
• C. T.B.
• D. Tetanus

Explanation: Typhoid is caused by Salmonella typhi. The organisms responsible for the disease are present in the stool and may also be found in urine. Consequently, they can be carried by water and contaminated food, potentially leading to severe epidemics. Polio is caused by Enterovirus. TB is caused by Mycobacterium tuberculosis. Tetanus is caused by Clostridium tetani.

58. Which is the most infectious disease?

• A. Hepatitis-B
• B. AIDS
• C. Cough and cold
• D. Malaria

Explanation: Hepatitis-B (serum hepatitis) can occur at any age, and its mode of transmission is through contact with infected blood. Infection is severe, often fatal, and is accompanied by symptoms such as loss of appetite, nausea, pale or whitish stool (due to a lack of bile), and jaundice. Even a very small amount, as little as 0.0002% of hepatitis B infected blood contact, is sufficient to transmit hepatitis B.

59. Interferons are synthesized in response to :

• A. Mycoplasma
• B. Bacteria
• C. Viruses
• D. Fungi

Explanation: Interferons are proteins that increase a cell's resistance to viral attacks by unmasking genes that synthesize antiviral proteins. In humans, three groups of interferons have been discovered: a) interferons from white blood cells; b) interferons from connective tissue fibroblasts; and c) interferons from lymphocytes.

60. Reason of lung cancer is :

• A. Coal mining
• B. Calcium fluoride
• C. Cement factory
• D. Bauxite mining

Explanation: Lung cancer is a disease where lung tissue grows out of control. This may lead to metastasis, invasion of adjacent tissue, and infiltration beyond the lungs. The vast majority of primary lung cancers are carcinomas of the lung, resulting from epithelial cells. One of the causes of lung cancer is exposure to coal dust. Exposure to coal dust can cause some coal mine workers to develop pneumoconiosis, or "black lung." This occurs when inhaled coal dust becomes embedded in the lungs, causing them to harden and making breathing difficult.