CBSE Questions for Class 12 Medical Biology Human Health And Disease Quiz 12 - MCQExams.com

• One dose of MMR vaccine is 93% effective against measles, 78% effective against mumps, and 97% effective against rubella. MMR is an attenuated (weakened) live virus vaccine.
• Vivotif (Typhoid Vaccine Live Oral Ty21a) is a live attenuated vaccine for oral administration only. The vaccine contains the attenuated strain Salmonella typhi.
• The smallpox vaccine protects people from smallpox by helping their bodies develop immunity to smallpox. The vaccine is made from a virus called vaccinia.
• One approach is to develop a vaccine to prevent this deadly disease. Clinical studies indicate that mucosal immunity may provide some protection against recurrent intestinal infection with E. histolytica, but there is no clear evidence that protective immunity develops after amoebic liver abscess.

• Ringworm is an infection of the skin caused by a fungal infection. Ring worm is characterised by the ring shaped rashes on the skin, itching, yellowing or decolouration of the affected area. It may also result in hair loss, if it infects the areas covered by hair. It is spread through skin contact with infected person.
  
• Filaria is caused by a roundworm Wuchereria bancrofti while Typhoid fever is due to bacterial infection caused by Salmonella Typhi

• Cancer is a class of diseases characterized by out-of-control cell growth. There are over 100 different types of cancer, and each is classified by the type of cell that is initially affected.
  
• Cancer harms the body when damaged cells divide uncontrollably to form lumps or masses of tissue called tumors. Tumors can grow and interfere with the digestive, nervous, and circulatory systems, and they can release hormones that alter body function. Tumors that stay in one spot and demonstrate limited growth are generally considered to be benign.
  

• Earthworms are soil red worms and are harmless. 

• Muscular dystrophy is a disease characterized by progressive degeneration of muscle fibers without the involvement nervous system. It has a hereditary origin.
  
• Tetany is overly stimulated nerve which causes involuntary muscle cramps and contractions. it caused by low level of calcium.
  
• Gout is caused by two conditions one due to excessive formation of uric acid second by the inability to excrete it. Uric acid gets deposited in the joints as monosodium salts.
  
• Myasthenia gravis is an autoimmune disease of neuromuscular junction caused by antibodies to cholinergic receptors. it is characterized by grave weakness of the muscles due to the inability of neuromuscular junctions to transmit impulses from nerve to the muscle.
  

• Serology is the study of blood serum and other bodily fluids. A serological test measures the number of antibodies present in the blood. 
• The antibody is an immunoglobulin protein. It is produced by B lymphocytes. It acts against a specific antigen. 
• The epitope is an antigen part to which an antibody attaches itself. 
• The antigen is mainly a proteinaceous substance that stimulates the production of antibodies.

Correct option: A
Explanation:

• Antiserum is the blood serum that contains specific antibodies against an infective organism or a poisonous substance. Antiserum consists of lymphocytes.
• Antiserums are produced in animals (like a horse, rabbit, sheep etc.,) and man in response to infection or intoxication or vaccination and may be used in another individual to confer immunity against a specific disease. 

Correct Option: C
Explanation:

• There are three stages in the development of AIDS. 
• The first stage is 'acute HIV infection' which is the earliest stage of HIV and develops within 2-4 weeks after a person is infected with HIV and here people have flu-like symptoms.
• The second stage is 'chronic HIV infection' where HIV continues to multiply in the body but at very low levels.
• The last and final stage of HIV infection is AIDS. AIDS is diagnosed when a person with HIV has a T lymphocytes count of fewer than 200 cells/cubic mm and/or one or more opportunistic infections.
• HIV uses the machinery of these T lymphocytes for replication and destroys them rapidly. 

• A vaccine is a preparation(or suspension) of a dead/attenuated pathogen of a disease which on inoculation (or injection) into a healthy person, provides temporary/permanent active not passive immunity. 
• Immunization is the process of giving a vaccine to a person to protect them against disease by inducing antibodies formation.
  
• Immunological memory is the ability of the immune system to respond more rapidly and effectively to pathogens that have been encountered previously.
  
• Vaccines utilise this to expose the body to the antigen without causing disease so that when the live pathogen infects the body, the response is rapid.
• Preformed antibodies are derived from the blood serum of previously infected people or animals and are often administered to another person in order to provide immediate, passive immunization against fast-acting toxins or microbes, such as those in snakebites or tetanus infections.