During muscle contraction in humans, the

MCQ

A
sarcomere does not shorten
✓
A band remains same
C
$A, H$ and $I$ bands shorten
D
actin filaments shorten.

✓

Answer

Correct option: B.

A band remains same

b
(b) : According to slidingfilament theory of muscle contraction, the actin and myosin filaments slide past each other with the help of crossbridge to reduce the length of the sarcomeres. The smallest unit of muscle contraction is a sarcomere (which is delineated by $Z$ lines). As a muscle contracts, the $Z$ lines come closer together (shortening sarcomere), the width ofthe $I$ bands decreases, the width of the $H$ zones decreases, but there is no change in the width of the $A$ band. During relaxation, crossbridges disappear and actin filaments slide back from Abands, the width of the $I$ bands and $H$ zones increases, but there is still no change in the width of the A band.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "M.C.Q (1 Marks)" from STD 11 - 17. Locomotion and movement→STD 11 - 17. Locomotion and movement — all question types→BIOLOGY STD 11 Science question papers→Rajasthan Board STD 11 Science question papers→Rajasthan Board question paper generator→

STD 11 - 17. Locomotion and movement — BIOLOGY STD 11 Science — Question

Answer

Need a full question paper?

Explore more

Similar questions