Skeletal muscles appear striated due to the presence of two characteristic proteins in alternating dark and light bands. Which of the following is a correct match of the protein with its light refractive property and color?
Protein Colour Property
(1) Myosin Light Anisotropic
(2) Actin Dark Anisotropic
(3) Myosin Dark Isotropic
(4) Actin Light Isotropic
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).
The H-Zone in the skeletal muscle fibre is due to
(1) the central gap between actin filaments extending through myosin filaments in the A-band
(2) extension of myosin filaments in the central portion of the A-band
(3) the absence of myofibrils in the central portion of A-band
(4) the central gap between myosin filaments in the A-band
Consider the diagram given below.
Parts labelled as A, B, C, D, E and F respectively indicate.
(1) Sacrum, ilium, pubis, femur, tibia and fibula
(2) Ilium, pubis, sacrum, femur, fibula and tibia
(3) Sacrum, pubis, ilium, femur, tibia and fibula
(4) Ilium, sacrum, pubis, femur, tibia and fibula
Pick out the correct match
(1) Sternum - 14
(2) Pelvis - 3
(3) Ribs - 20
(4) Face - 5
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
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
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
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
Ca+2 bind ________ in the skeletal muscles and leads to exposure of the binding site for ________ on the filament _______:
(1) Troponin, myosin, actin
(2) Troponin, actin, relaxin
(3) Actin, myosin, troponin
(4) Tropomysin, myosin, actin