Zoology MCQs for NEET — Practice Questions with Answers

Interferons are proteins that are produced by the cells in response to viral infections. They play a crucial role in the defense mechanism against viruses by interfering with viral replication within host cells. Therefore, they are termed as antiviral proteins.

Active acquired immunity occurs when exposure to a disease organism triggers the immune system to produce antibodies to that disease. It can be acquired through natural infection or through vaccines containing the antigen. Therefore, the correct answer is active acquired immunity.

Vaccination works by stimulating the immune system to produce antibodies against specific pathogens without causing the disease. These antibodies provide immunity and protect the body from future infections by the same pathogen. Thus, vaccination produces antibodies, making it the correct answer.

IgE (Immunoglobulin E) is the antibody that plays a crucial role in allergic reactions. When an allergen enters the body, IgE antibodies attach to mast cells and basophils, causing them to release histamine and other chemicals, which lead to allergy symptoms such as itching, swelling, and mucus production.

Salmonella is a genus of bacteria that is mainly associated with typhoid fever and other forms of gastroenteritis. Typhoid fever is caused specifically by the bacterium Salmonella typhi, which is transmitted through contaminated food and water.

Lymphocytes, a type of white blood cell, are responsible for the production of antibodies. There are two main types of lymphocytes: B cells and T cells. B cells are specifically involved in the production of antibodies that help the immune system to identify and neutralize pathogens like bacteria and viruses.

Passive immunity is provided when a person is given antibodies to a disease rather than producing them through their own immune system. This can happen through antibody-containing blood products such as immunoglobulin, or through maternal antibodies passed to a baby through breast milk.

Antibodies are complex glycoproteins. They are also known as immunoglobulins and play a crucial role in the immune response by identifying and neutralizing foreign objects like bacteria and viruses.

HIV primarily targets and destroys Helper T-Lymphocytes (CD4 cells). These cells are pivotal in coordinating the body's immune response. The destruction of these cells by HIV leads to a weakened immune system, making the body more susceptible to infections.

HIV/AIDS cannot be transmitted through casual contact such as sharing clothes, shaking hands, or hugging. It spreads through specific body fluids such as blood, semen, vaginal fluids, rectal fluids, and breast milk. Thus, utilization of clothes used by an AIDS patient does not cause infection.