Which of the following statements about striated muscles are false?
1. Thick filaments in the 'A' band are also held together in the middle of this band by a thin fibrous membrane called 'M' line.
2. In the centre of each 'I' band is an elastic fibre called 'Z' line which bisects it.
3. The thin filaments are firmly attached to the 'Z' line.
4. This central part of thick filament not overlapped by thin filaments is called the 'H' zone.
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.
-line
-line
-zone
-band
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
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.
Statement II: Actin is a motor protein that is able to convert chemical energy into mechanical energy
How does muscle cells change their shape?
