The functional region of an antibody that binds to an antigen is called the: MCQ with Answer and Explanation

The functional region of an antibody that binds to an antigen is called the:
A. Variable region
B. Disulfide bridge
C. Constant region
D. Fc region
Answer: Option A
Solution (By JKSSB Mock Tests)
The variable (V) region at the tips of the antibody Y-shape contains the antigen-binding site, which is specific to a particular antigen. The constant region determines the class (IgG, IgM, etc.) and effector functions. The Fc region binds to immune cell receptors. Variability in the V region is generated by gene rearrangement, allowing immense antibody diversity.

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Practice More Biology Questions

Question #1
Which of the following statements about viruses is INCORRECT?
A. They are obligate intracellular parasites.
B. They reproduce by binary fission.
C. They lack metabolic machinery.
D. They can have either DNA or RNA as genetic material.

Correct Answer: Option B


Explanation:
Viruses do not reproduce by binary fission; they replicate by hijacking host cell machinery. Binary fission is a method of asexual reproduction in bacteria. All other statements are correct.

This question belongs to: Science Biology
Question #2
Which of the following organisms belongs to Kingdom Monera?
A. Paramecium
B. Euglena
C. Bacillus
D. Agaricus

Correct Answer: Option C


Explanation:
Bacillus is a genus of rod-shaped bacteria, placed in Kingdom Monera because they are prokaryotic. Euglena and Paramecium are unicellular eukaryotes in Kingdom Protista. Agaricus (mushroom) belongs to Kingdom Fungi. Monera includes all prokaryotes like bacteria, cyanobacteria, and archaea. They are characterized by absence of true nucleus and membrane-bound organelles.

This question belongs to: Science Biology
Question #3
Assertion (A): RNA is usually single-stranded.
Reason (R): RNA contains deoxyribose sugar.
A. Both A and R are true, and R is the correct explanation.
B. A is false, but R is true.
C. A is true, but R is false.
D. Both A and R are true, but R is not the correct explanation.

Correct Answer: Option C


Explanation:
RNA is typically single-stranded (A true), but it contains ribose, not deoxyribose. Deoxyribose is in DNA. Thus R is false.

This question belongs to: Science Biology