Sarcomere is described as the part of myofibril between two
(1) M-lines
(2) Z-lines
(3) A-bands
(4) I-bands
Unit of contraction in a muscle fiber is:
1. Sarcomere
2. Muscle fiber
3. Actin
4. None
Match Column-I with Column-II:
Column-I | Column-II |
A. Structural and functional unit of a myofibril B. Protein of thin filament C. Protein of thick filament D. The central part of thick filament not overlapped by thin filament |
I. H-zone II. Myosin III. Sarcomere IV. Actin |
(1) A - I, B - II, C - III, D - IV
(2) A - I, B - III, C - II, D - IV
(3) A - I, B - IV, C - III, D - II
(4) A - III, B - IV, C - II, D - I
Dark bands (thick filaments) contain myosin and are called:
(1) A-bands or Isotropic band
(2) A-bands or Anisotropic bands
(3) I-bands or Isotropic bands
(4) I-bands or Anisotropic bands
During muscular contraction, which of the following events occur?
(i) H-zone disappears
(ii) A band widens
(iii) I band shortens
(iv) Width of A band is unaffected
(v) M line and Z line come closer
(1) (i),(iii),(iv) and (v)
(2) (i),(ii) and (v)
(3) (ii),(iv) and (v)
(4) (i),(ii) and (iii).
Read the following A to D statements and select the option that contains both correct statements:
A. Z-line is present in the centre of the light band.
B. Thin filaments are firmly attached to the M-line
C. The central part of thick filaments, not overlapped by thin filaments is called Z-band
D. Light band contains only thin filaments
(1) A and D
(2) B and C
(3) A and C
(4) B and D
Choose the letter from the figure that most appropriately corresponds to the structure:
I.A-band II. I-band III. Sarcomere IV. H-zone
V.Myosin VI.Actin, Troponin, Tropomyosin VII. Z –line
(1) I - E, II - D, III - F, IV - G, V - B, VI- C, VII - A
(2) I - E, II - D, III - C, IV - G, V - B, VI - A, VII - F
(3) I - E, II - D, III - F, IV - G, V - C, VI - A, VII - B
(4) I - E, II - D, III - F, IV - A, V - B, VI - C, VII - G
Light bands (thin filaments) contain actin and are called:
(1) A-bands or Isotropic band
(2) A-bands or Anisotropic bands
(3) I-bands or Isotropic bands
(4) I-bands or Anisotropic bands
Which of the following is correct about the given figure?
(1) The length of the thick and thin myofilaments has changed.
(2) Length of both anisotropic and isotropic band has changed.
(3) The myosin cross-bridges move on the surface of actin and the thin and thick myofilaments slide past each other.
(4) Length of the sacromere remains same.
Which of the following is not true regarding M line?
(1) Thin membrane
(2) Fibrous
(3) Holds thick filament of A band
(4) Keeps the Actin filament in centre