Actin Molecule

Q. Mention if the following statements are true (T) or false (F)
(ii) Dendrons bundled together form a nerve.

Q.

Assertion - Chloroplast is the site of photosynthesis

Reason- Mature plant cells have a large central vacuole.

Q.

What is a plastid ? What is the name of green plastids present in plant cells ?

Q. Which of the following occupies maximum volume inside a eukaryotic cell?

1. Ribosome
2. Mitochondrion
3. Nucleus
4. Cytoplasm

Q. Calcium receptive protein of muscles is

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

Q.

Which one of the following is wrongly matched?

1. Myosin – Contractile protein

2. Red muscle – Myoglobin

3. Troponin – Protein of myosin filament

4. Tendon – Connective tissue

Q. The generation of excitation-contraction coupling involves all the following events except

1. Formation of cross-linkages between actin and myosin
2. Release of calcium from troponin
3. Generation of end-plate potential
4. Hydrolysis of ATP to ADP

Q. Calcium receptive protein of muscles is

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

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.

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. 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. 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 the property of plastids?

1. They have double membranes

2. They are found only in plants

3. They help in giving shape to the cell

4. They contain coloured pigments such as chlorophyll

Q. Which part of the plant contains high amount of chromoplasts?

1. Stem
2. Root
3. Leaf
4. Flower

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