Question

Dark colour of beast muscles of a bird of flight is due to the high concentration of
a. Mitochondria
b. Haemoglobin
c. Myoglobin
d. Both myoglobin and mitochondria

Answer 1

Hint: Most of the birds use flight as the primary way of locomotion. Bright flight involves the mechanism which is similar to aircraft. Birds use opposite force to the direction of motion to execute the flight, this force is called aerodynamic force. The muscles which are involved in bird fly, named pectoral muscle, accessory muscle and tensor muscle.

Complete answer:
Bird flight is a high energy-dependent process. The bird needs a high amount of ATP from a fly. ATP production is the result of cellular respiration which takes place within the muscle cells of the bird.

A dark colour (red) of the beast muscle of birds comprise red muscle fibres. The red colour appears due to the high concentration of myoglobin present in the beast muscle. Myoglobin is similar to haemoglobin. Myoglobin is responsible for producing the required amount of ATP to sustain the flight. Myoglobin can bind iron and oxygen within the red muscle fibre. Myoglobin increases the oxygen entry into the muscle from the red blood cells. Then the inserted oxygen is transported to mitochondria of the muscle cells. Within the mitochondria, cellular respiration takes place by using oxygen. Cellular respiration leads to the production of night ATP. Produced ATP helps the bird to fly.

Hence, the correct answer is option (C).

Note: The other name of red muscle fibre is slow-twitch fibre. Red muscle fibre contracts at a relatively slow rate but in a steady mode. It requires a high amount of oxygen which is supplied by the myoglobin. The major characteristic of the red muscle cell is that it does not tend to fatigue.