Consider statements about human immunity: 1. Innate immunity is present from birth. 2. Acquired immunity develops after exposure to an antigen. 3. Vaccines provide natural immunity. Which are correct? MCQ with Answer and Explanation

Question

Consider statements about human immunity: 1. Innate immunity is present from birth. 2. Acquired immunity develops after exposure to an antigen. 3. Vaccines provide natural immunity. Which are correct?

A. 2 and 3 only

B. 1, 2 and 3

C. 1 and 3 only

D. 1 and 2 only

Answer: Option D

Solution (By JKExamLibrary)

Innate (natural) immunity is the non-specific defense mechanism present from birth, including physical barriers like skin and chemical barriers like stomach acid. Acquired (adaptive) immunity is highly specific and develops after the body is exposed to a specific pathogen or antigen, involving the production of antibodies and memory cells. Vaccines provide artificial immunity (specifically, artificial active immunity), not natural immunity, which is acquired through actual infection or from mother to child. Thus, statements 1 and 2 are correct.

This question belongs to: Science Biology

Request complete Subject PDF

Discuss this Question (0)

No comments yet. Be the first to start the discussion!

Practice More Biology Questions

Question #1

Share Report

The antibiotic that inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit is:

A. Cephalosporin

B. Tetracycline

C. Penicillin

D. Vancomycin

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option B

Explanation:
Tetracycline binds to the 30S ribosomal subunit, blocking attachment of aminoacyl-tRNA, thus inhibiting protein synthesis. Penicillin and cephalosporins inhibit cell wall synthesis, vancomycin also inhibits cell wall synthesis. Aminoglycosides like streptomycin also target 30S. Protein synthesis inhibitors exploit the difference between bacterial and human ribosomes.

This question belongs to: Science Biology

Question #2

Share Report

The largest artery in the human body is the:

A. Aorta

B. Carotid artery

C. Pulmonary artery

D. Coronary artery

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option A

Explanation:
The aorta is the main and largest artery originating from the left ventricle, distributing oxygenated blood to all parts of the body through its branches. The pulmonary artery carries deoxygenated blood to lungs. Coronary arteries supply the heart muscle, carotid arteries supply the brain. The aorta has a diameter of about 2-3 cm in adults.

This question belongs to: Science Biology

Question #3

Share Report

Consider statements about evolution: 1. Mutations provide raw material for evolution. 2. Genetic drift occurs in large populations. 3. Speciation can result from geographic isolation. Which are correct?

A. 1 and 3 only

B. 2 and 3 only

C. 1 and 2 only

D. 1, 2 and 3

View Answer & Solution Discuss

Get Complete Subject PDF for Science

Correct Answer: Option A

Explanation:
Mutations are random changes in DNA that create new alleles, providing the raw genetic variation necessary for natural selection. Genetic drift is the random change in allele frequencies, which has a significant effect primarily in small, isolated populations, not large ones. Geographic isolation prevents gene flow between populations, eventually leading to reproductive isolation and speciation. Thus, statements 1 and 3 are correct.

This question belongs to: Science Biology

Explore All Biology MCQs