During muscle contraction Size of A-bands remains the same Size of H-zone becomes smaller O Size of I-bands decreases All the above

in dry regions the leaf size of a tree becomes smaller It is so to

During muscle contraction (a) A band remains of length same (b) O band increases (c) H zone and M line disappear (d) I band increases € Membrane of Krause comes closer (f) Sarcomere lengthens

On contraction of alary muscles, the size of pericardial sinus

Go through the following statements During muscle contraction, the width of A-band remains constant while I-band shortens. During muscle contraction, the Ca^(2+) released from the SR bind to the troponin component of thin filament The process of muscle contraction is faster in smooth muscle as they have a well developed sarcoplasmic reticulum. The red muscle fibres have abundant mitochondria, low glycogen and poorly formed sarcoplasmic reticulum.

Assertion : In muscle contraction, length of both A-bands and I-bands decrease. Reason : Both myosin of A-band and actin of I-bands are contractile proteins and decrease in size during muscle contraction.

Statements A-bands of the muscle are dark and contain myosin I-band are the light bands and contain actin During muscle contraction the A-band contracts The part between the two Z-lines is called as sarcomere The central part of thin filament, not over-lapped by thick filament is called H-zone of the above statements.

Consder the diagram showing muscle structure below. Identify the events that occur during skeletal muscle contraction. I. I-band shortens II. A-band shortens III. H-zone shortens IV. Sarcomere contracts V. ATP changes to ADP and Pi Choose the option incorrect event(s).

The size of pupil decreases due to the contraction of