Zoology MCQs for NEET — Practice Questions with Answers

(d) : Diptheria, leprosy and plague are the bacterial diseases of humans. Diptheria is a serious air-borne contagious disease. It is caused by Cornybacterium diphteriae which is Gram-positive bacterium. It is inhaled through droplets and reaches to respiratory tract and infects it. Leprosy or Hansen's disease is a contact disease caused by bacterium Mycobacterium leprae. It degenerates the tissues and deform the body organs. Plague is a disease caused by bacterium Yersinia pestis or Pasteurella pestis.

(b) : Binding of antibodies to the antigens produces a large insoluble complex known as agglutination. It is a specific reaction, i.e., a particular antigen will only clump in the presence of its specific antibody. Each antibody has two antigen binding sites. It combines with two antigens, causing them to aglutinate.

(c): Entamoeba histolytica is a monogenetic parasite, i.e., living in a single host, in the large intestine of humans. It causes amoebiasis or amoebic dysentery.

(d) : Interferon is a group of proteins that increases the resistance of cells to viral infection. Interferon also acts as cytokines and can enhance some immune responses. Three types of interferons have so far been discovered, alpha, beta and gamma, all of which have immune-modulating effects. Interferons are used in the treatment of cancer and autoimmune diseases.

(d) : DPT vaccine is a combined vaccine against diphtheria, whooping cough (pertussis), and tetanus now replaced by the DTaP/IPV/Hib and DTaP/IPV vaccines

(d): Common cold can take place from one person to other as it it a communicable in nature. A healthy person can get infected by being in close vicinity of infected person when he/she sneezes, coughs, as the droplets generted by sneeze and cough contain infecting agents. Typhoid occurs by the intake of contaminated water & food. While ringworm is one of the skin disease which can transfer from one person to other by the use of infected towel & handkerchief. AIDS (Acquired Immuno deficiency) does not occur or transfer by shanking hands.

(a) : AIDS is caused by HIV virus, Gonorrhoea is caused by bacteria Neisseria gonorrhoeae. Diphtheria is caused by bacteria Corynebacterium diphtheria. Ringworm disease is caused by fungus Trichophyton, Epidermophyton and Microsporum, tuberculosis is caused by a bacterium called Mycobacterium tuberculosis.

(a) : Normal cells show the property of contact inhibition, by virtue of which contact with other cells inhibits their uncontrolled growth. Cancer cells appears to have lost this property.

(a): Salmonella typhi (Causal organism of typhoid) is transmitted by faecal oral route and not by a vector. The alpha viruses are transmitted by insect vectors, most commonly by mosquitoes. Plasmodium (malarial parasite) is transmitted by female Anopheles mosquito and Wuchereria bancrofti (filarial worm) is transmitted by female Culex mosquito

(b): DDT (Dichloro diphenyl trichloroethane) is a colourless, crystalline, tasteless and almost odourless organochloride known for its insecticidal properties. DDT is not derived from any plant rather it is prepared by the chemical reactions of some chemical compounds.
Opioids (opiates) are the analgesic drugs that are derived from latex of unripe fruits of poppy plant, Papaver somniferum. Similarly, cocaine and cannabinoids are the drugs derived from Erythroxylon Coca (Coca plant) and Cannabis sativa (Hemp plant) respectively.