
The H-zone in the skeletal muscle fibre is due to

Important Questions on Locomotion and Movement
During muscular contraction which of the following events occur?
(a) 'H' zone disappears
(b) 'A' band widens
(c) 'I' band reduces in width
(d) Myosin hydrolyzes ATP, releasing the ADP and Pi
(e) Z-lines attached to actins are pulled inwards.
Choose the correct answer from the options given below.







Statement II: Actin is a motor protein that is able to convert chemical energy into mechanical energy




-line
-line
-zone
-band

Reason (R): The above said molecules have a role in masking and unmasking the active sites on actin.

(i) Muscles show three essential properties such as excitability, conductivity and contractility.
(ii) Muscular tissue is endodermal in origin except muscle of iris and ciliary body.
(iii) The cytoplasm of muscle fibre has several myofibrils.
(iv) Skeletal muscles exhibit slow and prolonged contractions.
(v) The regular arrangement of myosin and actin filaments is responsible for alternate dark and light bands of striated muscle.

Assertion (A): Skeletal muscles have very limited power of regeneration.
Reason (R): Satellite cells are present in them.
The correct option among the following is

How does muscle cells change their shape?



Select the correct option for the given statements in reference to muscle contraction.
Statements.
X = Actin slides over myosin
Y = Light meromyosin join with actin
Z = Myosin and Actin actually do not contract

