Titin and Functions

Q. Which of the following is a regulatory protein for muscles?

1. Tubulin
2. Tropomyosin
3. Myosin
4. All the above

Q. Active sites are unmasked when calcium binds with a subunit of

1. Troponin
2. Tropomyosin
3. Actin
4. Myosin

Q. Which of the following sarcomeric protein help the sarcomere to spring after recoil and prevent overstretching

1. Titin
2. Actin molecule
3. Myosin molecule
4. Tropomyosin

Q. When a muscle is at rest, what blocks myosin from binding to actin?

1. Acetylcholine
2. ATP
3. $C{a}^{++}$
4. Troponin

Q. During muscle contraction

1. I band shortens
2. A band shortens
3. length of the sarcomere remains the same
4. all of these

Q. Which of the following sarcomeric protein help the sarcomere to spring after recoil and prevent overstretching

1. Tropomyosin
2. Actin molecule
3. Myosin molecule
4. Titin

Q. Which of the following sarcomeric protein help the sarcomere to spring after recoil and prevent overstretching

1. Tropomyosin
2. Actin molecule
3. Myosin molecule
4. Titin

Q. Source of Calcium for skeletal muscle contraction is only from SR or from extracellular fluid also?