Actin Molecule

Q. State the difference between :
Cytoplasm and protoplasm.

Q.

Differentiate between the following:

Glucocorticoids and mineralocorticoids.

Q.

Write true or false. If false change the statement so that it is true.

(a) Actin is present in the thin filament

(b) H-zone of striated muscle fibre represents both thick and thin filaments.

(c) Human skeleton has 206 bones.

(d) There are 11 pairs of ribs in man.

(e) Sternum is present on the ventral side of the body.

Q. Sarcomere is the part between

1. 2 I bands
2. 2 Z lines
3. 2 A bands
4. 2 H bands

Q. G actin or globular actin is the monomer of

1. filamentous actin
2. none of the above
3. troponin
4. tropomyosin

Q.

Which one of the following pairs of chemical substances is correctly categorized?

1. Secretin and rhodopsin – Polypeptide hormones

2. Pepsin and prolactin – Two digestive enzymes secreted in stomach

3. Troponin and myosin – Complex proteins in striated muscles

4. Calcitonin and thymosin – Thyroid hormones

Q.

Label the different components of actin filament in the diagram given below.

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

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

Q. Aleurone layer helps in

1. Utilisation of stored food
2. Protection of embryo
3. All of the above
4. Storage of food in endosperm

Q. Which of the following is the function of troponin?

1. It slides over myosin
2. It helps in the fusion of actin and myosin
3. It covers myosin and prevents attachments of actin and myosin
4. It causes ${\mathrm{Ca}}^{+2}$ release

Q. Which one of the following types of cells lack nucleus in humans?

1. Neutrophils

2. Eosinophils

3. Erythrocytes

4. Monocytes

Q.

The cross bridges involved in muscle contraction are located on the ________________.

1. myosin myofilaments

2. actin myofilaments

3. tropomyosin

4. dystrophin

Q.

Fill in the blank spaces:
Thin filament of myofibril contains 2 ‘F’ actins and two other proteins namely
___ and ___

Q.

Which one of these is present in animal cell but absent in plant cell?

1. Vacuole

2. Golgi

3. Mitochondria

4. Centrosome

Q.

Who coined the term ‘protoplasm’ for the fluid substance of the cell?

Q. Write the name of any one amino acid, sugar, nucleotide and fatty acid.

Q.

The plastid which store food is:

1. (a) Leucoplast

2. (b) Chromoplast

3. (c) Chloroplast

4. (d) Tonoplast

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.

Collagen is found in yellow elastic fibre.

1. True
2. False

Q.

Find out the false statements

1. Golgi apparatus is involved with the formation of lysosomes.

2. Nucleus, mitochondria and plastid have DNA; hence they are able to make their own structural proteins.

3. Mitochondria is said to be the power house of the cell as ATP generated in them.

4. Cytoplasm is called as protoplasm.

Q.

Name the term for the fluid substance of cell.

Q. Protein complex formed during cross bridge is known as:

1. Myosin molecule
2. Actin molecule
3. Actomyosin complex
4. During muscle contraction extra protein layer present in between actin and myosin molecule

Q. Fill up the blanks with the terms given below in the box.
Plastids contain .

1. pigments
2. pre-existing
3. vacuoles
4. wall
5. cell

Q.

Name the cytoplasm of axon.

Q.

Which of the following are covered by a single membrane?

1. Mitochondria

2. Vacuole

3. Nucleus

4. Plastid.

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

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

Q.

Which hormone stimulates the stomach to secrete gastric juice?

1. Gastrin

2. Parathormone

3. Thyroxine

4. Insulin

Q. Compared to the resting state, vigorously contracting skeletal muscle exhibits

1. an increased conversion of pyruvate to lactate
2. decreased oxidation of pyruvate to carbon dioxide and water
3. decreased NADH/NAD+ ratio
4. decreased concentration of AMP

Q.

Which is the most widely occurring plastid?

Q. In resting stage, binding sites for myosin on actin filaments are masked by

1. Troponin
2. Light meromyosin
3. Heavy meromyosin
4. Calcium ions