Question

Following are given differences between red muscle fibres and white muscle fibres. Which of them is/are incorrect?

	Characteristic	Red fibres	White fibres
$\left(a\right)$	Myoglobin content	High	Low
$\left(b\right)$	Sarcoplasmic reticulum content	High	Low
$\left(c\right)$	Number of mitochondria	High	Low
$\left(d\right)$	Type of respiration	Aerobic	Anaerobic

• A. Only $\left(b\right)$
• B. $\left(b\right)$ and $\left(c\right)$
• C. $\left(b\right)$ and $\left(d\right)$
• D. All the characteristics are correctly matched

Answer 1

Answer: (A)

Muscle contains a red coloured oxygen storing pigment called myoglobin. Myoglobin content is high in some of the muscles which gives a reddish appearance. Such muscles are called the Red fibres. These muscles also contain plenty of mitochondria which can utilise the large amount of oxygen stored in them for ATP production. These muscles, therefore, can also be called aerobic muscles. On the other hand, some of the muscles possess very less quantity of myoglobin and therefore, appear pale or whitish. These are the White fibres. Number of mitochondria are also few in them, but the amount of sarcoplasmic reticulum is high. They depend on anaerobic process for energy.