CBSE Questions for Class 12 Medical Biology Human Health And Disease Quiz 16 - MCQExams.com

Correct Option: A

Explanation:

• The vaccine is a method of preparation to boost the immune response against the disease with help of a whole microorganism either live or attenuated or in killed form of antigenic proteins are introduced inside the body. 
• The microorganism used could be bacteria or viruses. Vaccines generate memory B and T-cells that recognise the pathogen quickly on exposure.

• HIV is an enveloped retrovirus. Each virus particle contains two copies of an RNA genome. Hence, HIV is a type of retrovirus that has an envelope enclosing the diploid RNA genome.
• HIV infects white blood cells in the body’s immune system called helper T cells. The virus attaches itself to the helper T cells. 
• In macrophages of the host cell, the RNA genome converts into DNA by reverse transcriptase enzyme and incorporated into the host DNA to produce viral DNA.
• Without reverse transcriptase, the viral genome couldn't become incorporated into the host cell, and couldn't reproduce.

Aschelminths or Nemathelminthes are either free-living or parasitic animals.

• The Giant Intestinal roundworm species belonging to the phylum Nemathelminthes is an endoparasite living in the human intestine. 

• These roundworms cause a disease called Ascariasis. 

• They usually live inside the intestine and causes obstruction to the intestinal passage.

• So, the correct answer is Nemathelminthes.

A.Myasthenia gravis - a chronic autoimmune neuromuscular disease that causes weakness in the skeletal muscles, which are responsible for breathing and moving parts of the body, including the arms and legs. 

B.Rheumatoid arthritis - is a long-term autoimmune disorder that primarily affects joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest.

C.Parkinson’s disease - affects the nerve cells in the brain that produce dopamine. its  symptoms include muscle rigidity, tremors, and changes in speech and gait.

D.Hay fever -  is an allergic reaction to environmental allergens such as pollens, dust mite, moulds and animal hair. Avoiding allergic triggers and taking appropriate treatments are the best ways to reduce the frequency of hay fever symptoms.

• Cryobiology is the branch of biology that deals with effects of low temperatures on living things. 
• Teratology is the branch of science which deals with the study of congenital abnormalities and abnormal physiological development. 
• Molecular biology is the branch of biology which deals with the structure and function of the essential macromolecules. The major application of molecular biology to prevention and early detection of cancer and other diseases by identification of certain genes. 
• Gerontology is the branch of science which deals with the study of old age, the process of aging, and the problems of aged people.

• Rheumatoid Arthritis is an autoimmune disorder affecting the joints of the body, mainly the hand and feet. 
• An autoimmune disorder means a disorder in which body immune system attack self-cells as it loses the ability to differentiate between the pathogen or disease-causing agent and self-cells and therefore, start making antibodies against own cells in a substantial amount.