Biology Immunity MDCAT 2014
PMDC Verified Question 97 of 99
Antibodies are proteins and made up of how many polypeptide chains?
A
One
B
Three
C
Two
D
Four
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: Four
Concept:

Immunoglobulins are large, complex glycoproteins characterized by a standardized, multi-chain quaternary structure.

Formula:

None

Solution:

  • A standard monomeric antibody (like IgG) is composed of exactly four polypeptide chains.


  • These include two identical longer chains (Heavy chains) and two identical shorter chains (Light chains).


  • They are held together in a Y-shape by disulfide bridges.


Why other options are incorrect:

  • Antibodies are not simple single or dimeric chains; the fundamental unit universally requires four polypeptides to form the binding sites correctly.

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