Muscle fatigue occurs due to the accumulation of

1.  $C{O}_2$

2.  Myosin ATPase

3.  Lactic acid

4.  Creatine phosphate 

 

Contractile unit of muscle is part of myofibril between

1.  Z-line and l-band

2.  Z-line and Z-line

3.  Z-line and A-band

4.  A-band and l-band 

Which of the following are involved in the formation of acetabulum?

a. llium

b. ischium

c. Pubis

1.  a & b only

2.  b & c only

3.  a & c only

4.  a, b & c 

The total number of bones in the limb of a man is

1.  24

2.  30

3.  14

4.  21

Identify the structure marked ‘X’

1. Humerus

2. Radius

3. Scapula

4. Clavicle

Sarcomere is described as the part of myofibril between two

(1) M-lines

(2) Z-lines

(3) A-bands

(4) I-bands

The fusion of which set of bones forms the coxal bone of the pelvic girdle?

(1) Malleus, incus and stapes

(2) Ilium, scapula and ischium

(3) Ilium, ischium and pubis

(4) Incus, ilium and sternum

Each myosin filament comprises all the following,

except

(1) Each myosin filament is a polymerised protein, many monomeric proteins called meromyosins constitute one thick filament

(2) Actin binding sites and ATP binding sites are present on the cross-arm which is part of HMM

(3) Myosin tail is composed of LMM which binds to tropomyosin

(4) The globular head of myosin is an active ATPase enzyme

Choose the correct statement.

1. In a resting muscle fibre, a subunit of troponin masks the active binding sites on myosin for actin filaments

2. The myosin monomer called meromyosin has a globular head which has binding sites for ATP and active sites for actin

3. A motor neuron along with the muscle fibres connected to it constitute motor-end plate

4. The Z-lines attached to A-bands are pulled inwards towards the H-zone causing shortening of sarcomere

Red muscle fibres differs from white muscle fibres in having

1. More sarcoplasmic reticulum

2. Less myoglobin content

3. More number of mitochondria

4. High lactic acid due to anaerobic oxidation