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).

Which of the following is true for the labelled parts in the figure below?

(1) A - Z-line              - located at centre of I - band

(2) B - Thin filament   - occurs in A-band only

(3) C - Thick filament  - confined to I-band

(4) D - H-zone           - located at centre of M-line

What is the oxidation state of iron in haemoglobin?

(1)  Fe^-

(2)  Fe²⁺

(3)  Fe³⁺

(4)  Fe⁴⁺

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

An example of stretch reflex triggered by passive muscle movement is the

(1) tendon reflex               

(2) ipsilateral reflex

(3) flexor reflex         

(4) patellar reflex

Gerdy fibres are 

(1) ligament of neck       

(2) ligament of ankles

(3) ligament of palm       

(4) ligament of face.

Achondroplasia is a disease related with the defect in the formation of 

1. membrane

2. cartilage

3. mucosa

4. none of these

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

In old age, stiffness of joints is due to the 

(1) hardening of bones

(2) inefficiency of muscles

(3) decrease in synovial fluid

(4) enlargement of bones

Oxygen content reduction makes the glycolyse (glycogenesis) intensity increased due to

(1) increase of ADP concentration in cell

(2) increase of ${\mathrm{NAD}}^{+}$ concentration in cell

(3) increase of ATP concentration in cell

(4) increase of concentration of peroxides and free radicals