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:

(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

Following is the figure of actin (thin) filaments. Identify A, B and C:

1. A - Tropomyosin, B - Troponin, C - F-actin

2. A - Troponin, B - Myosin, C - Tropomyosin

3. A - Troponin, B - Tropomyosin, C - Myosin

4. A - Troponin, B - Tropomyosin, C - F-actin