NEET Practice Questions (MCQs) with Answers & Solutions

Antibodies are the protein (glycoproteins) called immunoglobulins, These are produced by the lymphocytes in response to entry of a foreign substance or antigen into the body. Lipoproteins are the micellar complex of protein and lipids.
Steroids are a group of lipids derived from a saturated compound cyclopentano perhydrophenanthrene which has a nucleus of four rings.
Prostaglandin is a group of organic compounds derived from essential fatty acids and causing a range of physiological effects in animals.

(d): Histiocyte are phagocyte found mainly in connective tissue. Although normally non-motile, it can become converted into a mobile, amoeboid macrophage. Histiocytes are large, irregularly shaped cells with granular, vacuolated cytoplasm. They are associated with inflammatory conditions, and are especially found near tissue haemorrhages. Mast cells are the connective tissue cells that contain heparin and histamine in their granules. Important in cellular defence mechanisms including blood coagulation needed during injury or infection. Plasma cells are leucocyte formed from an antigen- stimulated B-lymphocytes.

The so called tertain periodicity of Plasmodium vivax refers to the erythrocytic phase.

(b): Hybridoma is a cell produced by the fusion of an antigen-producing cell and a multiple myeloma cell. This hybrid cell is capable of producing a continuous supply of antibody.

Myelomas are B lymphocyte tumors that readily fuse with plasma cells to form antibody- producing hybridomas.

(d): Communicable diseases are infectious diseases which are caused by pathogens and spread from infected person to healthy person. These are of two types- contagious diseases (which are transmitted from infected person to healthy person through contact e.g., syphilis, chickenpox, etc.) and non-contagious diseases (which are transmitted from infected person to healthy persons through an agency of water, food or air or by some carrier or vector, e.g., ascariasis, cholera, filariasis, plague etc).

(c) : Attenuation is the lessining or reduction of virulence of a pathogenic bacterium or virus. The phenomenon was first noticed by Louis Pasteur (1822-95), who developed it as a means of producing strains of bacteria suitable for vaccination. Attenuated strains of bacteria are obtained by successive subculturing in controlled conditions, whereas attenuated virus may be obtained by ultraviolet irradiation. Such strains of bacteria or viruses are used to induce active immunity by inoculation.

(d) : Anthrax is an acute infectious disease caused by the spore forming bacterium Bacillus anthracis. The long-lived spores of this organism can also be found in soil and their stability makes them an ideal bioweapon.

It most commonly occurs in wild and domestic lower vertebrates (cattle, sheep, goats camels etc) but it can also occur in humans when they are exposed to infected animals or tissue from infected animals. Anthrax infections can occur in three forms - cutaneous, inhalation and gastrointestinal

(c) : Opium is a narcotic drug that is obtained from the unripe seedpods of the opium poppy (Papaver somniferum), a plant of the family papaveraceae. Opim is obtained by slightly incising the seed capsules of the poppy after the plant's flower petals have fallen. The slit seedpods exude a milky latex that coagulates and changes colour, turning into a gum like brown mass upon exposure to air. This raw opium may be ground into a powder, sold as lumps, cakes, or bricks, or treated further to obtain such derivatives as morphine, codeine, and heroin. Opium and the drugs obtained from it are called opiates.

People get malaria by being bitten by an infective female Anopheles mosquito. Only Anopheles mosquitoes can transmit malaria and they must have been infected through a previous blood meal taken from an infected person.

Because the malaria parasite is found in red blood cells of an infected person, malaria can also be transmitted through blood transfusion, organ transplant, or the shared use of needles or syringes contaminated with blood. Malaria may also be transmitted from a mother to her unborn infant before or during delivery(vertical transmission through placental defect).

(c): Memory cells refer to memory B cells. It is a B cell sub-type that are formed following primary infection. When a B cell is activated, by recognising a specific antigen, it proliferates to form antibody producing plasma cells and long-lived memory cells. The memory B cells are specisics or the antigen that first stimulated their production. If this antigen is encountered again, memory B cells can recognise it and quickly proliferate. This forms a new generation of antibody-producing plasma cells. This means that the antibody response is much more rapid and specific in subsequent infections than in primary infection, reducing the chance of symptom development. This is the principle behind vaccination.