Q.91 Match the following molecules in Group I with their function in Group II
Group I
P. Transferrin
Q. Insulin
R. 𝛼-macroglobulin
S. Fibronectin
Group II
(i) Uptake of glucose
(ii) Binds iron
(iii) Substratum for cell attachment
(iv) Proteinase inhibitor
(v) Binds to oxygen in RBC
(A) P-ii; Q-i; R-iv; S-iii
(B) P-ii; Q-i; R-v; S-iii
(C) P-ii; Q-i; R-iv; S-ii
(D) P-i; Q-iii; R-ii; S-v

Transferrin binds iron, insulin regulates glucose uptake, alpha-macroglobulin inhibits proteinases, and fibronectin supports cell attachment. The correct matching is option (A): P-ii, Q-i, R-iv, S-iii.

Group I Functions

Transferrin (P) transports iron in blood plasma, binding ferric ions to deliver them to tissues like bone marrow, preventing free radical damage.
Insulin (Q) is a hormone that promotes glucose uptake by cells via GLUT4 transporters, essential for blood sugar regulation.
Alpha-macroglobulin (R) acts as a broad-spectrum proteinase inhibitor, trapping proteases to protect tissues from degradation.
Fibronectin (S) functions as an extracellular matrix glycoprotein, providing a substratum for cell adhesion and migration.

Option Analysis

• (A) P-ii; Q-i; R-iv; S-iii: Correct. Matches transferrin to iron binding (ii), insulin to glucose uptake (i), α-macroglobulin to proteinase inhibition (iv), fibronectin to cell attachment (iii).

• (B) P-ii; Q-i; R-v; S-iii: Incorrect. Alpha-macroglobulin does not bind oxygen in RBCs; hemoglobin performs that role (v).

• (C) P-ii; Q-i; R-iv; S-ii: Incorrect. Fibronectin does not bind iron; transferrin handles that (ii).

• (D) P-i; Q-iii; R-ii; S-v: Incorrect. Transferrin is not for glucose uptake (i), insulin not for cell attachment (iii), α-macroglobulin not for iron binding (ii), fibronectin not for oxygen binding (v).