Question

Match the following.

$\begin{array}{cc}\text{Column I}& \text{Column II}\\ \text{i. Troponin}& \text{a. Blocks the attachment site for the myosin cross bridge}\\ \text{ii. Tropomyosin}& \text{b. Has a myosin binding site}\\ \text{iii. Actin}& \text{c. Complex of 3 polypeptide units}\end{array}$

• A. i).→ c ., ii). → b., iii). →a
• B. i). →b., ii). → a., iii). →c
• C. i). → c., ii). → a., iii). →b
• D. i) →a., ii). → c., iii). →b

Answer 1

The correct option is C

i). → c., ii). → a., iii). →b

The thin filament is made of three separate proteins: actin, troponin, and tropomyosin. Actin has a myosin binding site for the cross bridge formation.
Troponin is a complex of three Polypeptide units(Troponin C, I and T). In a relaxed muscle, tropomyosin blocks the attachment site for the myosin cross bridge, thus preventing contraction.