Zoology · Biomolecules

NEET (UG) 2023 — Question 126

Given below are two statements : one is labelled as Statement I and the other is labelled as Statement II :

Statement I: A protein is imagined as a line, the left end represented by first amino acid (C-terminal) and the right end represented by last amino acid ( N -terminal)

Statement II: Adult human haemoglobin, consists of 4 subunits (two subunits of $\alpha$ type and two subunits of $\beta$ type.)

In the light of the above statements, choose the most appropriate answer from the options given below:

Option A:
Both statements I and II are incorrect.
Option B:
Statement I is correct and Statement II is incorrect.
Option C:
Statement I is incorrect and Statement II is correct.
Correct
Option D:
Both statements I and II are correct.

Answer: C

Step-by-step solution

By convention, a polypeptide chain is represented from left to right as $N$ -terminal (first amino acid with free $\ce{-NH2}$ ) to $C$ -terminal (last amino acid with free $\ce{-COOH}$ ). Statement I reverses these assignments, calling the left end C-terminal and the right end N-terminal, so Statement I is incorrect. Adult human haemoglobin is a tetramer $\alpha_2\beta_2$ , containing two $\alpha$ -type and two $\beta$ -type subunits. Therefore Statement II is correct. The correct choice is C.

Answer key and solution verified before publishing.

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Exam: NEET (UG) 2023
Paper: 2023 paper
Subject: Zoology
Chapter: Biomolecules
Topic: Proteins

Answer: C

Step-by-step solution

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