Actin Molecule

Q.

Match the following.

$\begin{array}{cc}\text{Column I}& \text{Column II}\\ \text{i. Troponin}& \text{a. Blocks the attachment site for the myosin cross bridge}\\ \text{ii. Tropomyosin}& \text{b. Has a myosin binding site}\\ \text{iii. Actin}& \text{c. Complex of 3 polypeptide units}\end{array}$

1. i). →b., ii). → a., iii). →c

2. i). → c., ii). → a., iii). →b

3. i) →a., ii). → c., iii). →b

4. i).→ c ., ii). → b., iii). →a

Q. In the thin filament of skeletal muscle fiber, a small globular protein that masks the active sites on the actin, is

1. G-actin
2. Actin
3. Tropomyosin
4. Troponin
5. Myosin

Q. Calcium receptive protein of muscles is

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

Q. What is the location of troponin in the process of muscle contraction?

1. Attached to myosin filament
2. Attached to tropomyosin
3. Attached to myosin cross bridge
4. Attached to T-tubule

Q.

Which of the following is not a component of a thin filament?

1. troponin

2. tropomyosin

3. actin

4. myosin

Q.

Which one of the following is wrongly matched?

1. Red muscle – Myoglobin

2. Troponin – Protein of myosin filament

3. Tendon – Connective tissue

4. Myosin – Contractile protein

Q.

Label the parts of the actin molecule and recognise the events 4 and 5 in the presence/absence of calcium.

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1. 1.Actin 2.Tropomyosin 3.Troponin 4.Sites exposed 5.Sites Blocked

2. 1.Troponin 2.Actin 3.Tropomyosin 4.Sites Blocked 5.Sites Exposed

3. 1.Actin 2.Tropomyosin 3.Troponin 4.Sites Blocked 5.Site Exposed

4. 1.Tropomyosin 2.Actin 3.Troponin 4.Site Exposed 5.Site Blocked

Q. In the thin filament of skeletal muscle fiber, a small globular protein that masks the active sites on the actin, is

1. G-actin
2. Actin
3. Tropomyosin
4. Troponin
5. Myosin

Q.

Which of the following is not a component of a thin filament?

1. Actin

2. Myosin

3. Troponin

4. Tropomyosin

Q.

Which one of the following is wrongly matched?

1. Red muscle – Myoglobin

2. Tendon – Connective tissue

3. Troponin – Protein of myosin filament

4. Myosin – Contractile protein