Q.103. Match the proteins in Column I with the organs in which they are maximally expressed in
Column II.
Column I
P. Keratin
Q. Surfactants
R. Pro-carboxypeptidase
S. Albumin
Column II
(i) Liver
(ii) Pancreas
(iii) Lung
(iv) Skin
(A) P-(iv), Q-(i), R-(iii), S-(ii)
(B) P-(iii), Q-(iv), R-(ii), S-(i)
(C) P-(iv), Q-(iii), R-(ii), S-(i)
(D) P-(i), Q-(ii), R-(iii), S-(iv)
Keratin protects skin as a structural protein, while surfactants reduce lung surface tension. Pro-carboxypeptidase activates in the pancreas for digestion, and albumin synthesizes mainly in the liver for blood transport. The correct match is option (C).
Protein Functions
Keratin forms tough filaments in epithelial cells, maximally expressed in skin for barrier protection. Surfactants, produced by type II alveolar cells, prevent lung collapse and are highest in lung tissue. Pro-carboxypeptidase, a pancreatic zymogen, converts to active carboxypeptidase by trypsin for protein digestion, peaking in pancreas. Albumin maintains osmotic pressure and transports molecules, synthesized primarily by liver hepatocytes.
Correct Matching
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P. Keratin → (iv) Skin: Provides mechanical strength to epidermis and hair.
-
Q. Surfactants → (iii) Lung: Essential for alveolar stability in respiration.
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R. Pro-carboxypeptidase → (ii) Pancreas: Secreted as zymogen in pancreatic juice.
-
S. Albumin → (i) Liver: Major site of production at 10-15g/day.
This aligns with option (C): P-(iv), Q-(iii), R-(ii), S-(i).
Option Analysis
| Option | P-Keratin | Q-Surfactants | R-Pro-carboxypeptidase | S-Albumin | Correct? |
|---|---|---|---|---|---|
| (A) | (iv) Skin | (i) Liver | (iii) Lung | (ii) Pancreas | No – Surfactants not liver; albumin not pancreas |
| (B) | (iii) Lung | (iv) Skin | (ii) Pancreas | (i) Liver | No – Keratin not lung; surfactants not skin |
| (C) | (iv) Skin | (iii) Lung | (ii) Pancreas | (i) Liver | Yes – Matches all primary expressions |
| (D) | (i) Liver | (ii) Pancreas | (iii) Lung | (iv) Skin | No – All mismatched |
Exam Relevance
This MCQ tests tissue-specific protein expression in molecular biology and physiology, common in NEET/Biotech exams. Understanding zymogen activation and organ roles aids genetics/biochemistry prep.
