Free Biodiversity and Variety of Life MCQs with Answers

261. Which virus that infects humans has no vector and is unable to survive outside human body?

• A. Polio virus
• B. Mumps virus
• C. Chicken pox virus
• D. All of these

Explanation: All viruses cause infection in human beings and get transferred by specific vector. Viruses always depends on living host for their survival.

262. Polio vaccine is given by:

• A. Spray
• B. Tablets
• C. Oral drops
• D. Local application

Explanation: Live vaccine of polio is given orally, while killed vaccines given by injection.

263. Which of the following is the simplest forms of pathogens causing disease?

• A. Viruses
• B. Prions
• C. Fungus
• D. Amoeba

Explanation: Prions are simplest form of pathogens because they are only proteins structurally. Viruses are nucleoproteins. Fungi is multicellular and eukaryotic organisms. Amoeba is eukaryotic and unicellular organism.

264. Which is not a viral disease?

• A. AIDS
• B. Malaria
• C. Chicken pox
• D. Influenza

Explanation: Malaria is caused by Plasmodium which is animal like protist.

265. Oral herpes is caused by:

• A. HIV
• B. HCV
• C. HSV-2
• D. HSV-I

Explanation: The causative agent of oral herpes is Herpes Simplex Virus type 1.

266. Which of the following diseases is caused by a viroid?

• A. AIDS
• B. Hepatitis B
• C. Hepatitis C
• D. Hepatitis D

Explanation: The only known human disease caused by a viroid is hepatitis D.

267. _ is known to cause cancers in animals.

• A. Polio virus
• B. HBV
• C. HIV
• D. Rous sarcoma virus

Explanation: Rous sarcoma virus (RSV) is an Oncovirus, which is known to cause sarcomas (tissue cancers) in fowls.

268. Major Cells that are infected by HIV are:

• A. B-lymphocytes
• B. T-Helper cells
• C. Natural killer cells
• D. T-Lymphocytes

Explanation: HIV attacks on specific type of immune cell in the body, known as T-helper cells. When HIV destroys these cells, then it becomes difficult for the body to fight against the infections.

269. It acts as a template strand for reverse transriptase:

• A. Viral DNA
• B. Host DNA
• C. Viral RNA
• D. T-Lymphocytes

Explanation: HIV is equipped with reverse transcriptase along with the other essential enzymes. Reverse transcriptase is responsible for reverse transcription, during which viral genomic ssRNA is converted into viral dsDNA in the cytoplasm of herlper T-cells.

270. Attachment of HIV DNA with host DNA is done via action of:

• A. lntegrase
• B. Reverse transcriptase
• C. Protease
• D. Nuclease

Explanation: HIV integeration is the insertion of HIV genetic material into the genome of the infected cell. This process is completed with the help of integrase.