Assertion (A): Red fibres in muscles have a high content of myoglobin,...
Understanding the Assertion and Reason
The question revolves around the characteristics of muscle fibres, specifically red fibres, and their energy metabolism.
Assertion (A) Explained
- Red fibres, or slow-twitch fibres, are indeed rich in myoglobin, a protein that binds oxygen.
- This myoglobin content gives these fibres their reddish appearance, as it contains heme, which is responsible for the red color.
Reason (R) Explained
- The statement that red fibres primarily rely on anaerobic metabolism is incorrect.
- In reality, red fibres are adapted for aerobic metabolism, utilizing oxygen to generate energy efficiently over prolonged periods.
Conclusion
- Since Assertion (A) is true, but Reason (R) is false, the correct answer is option 'C'.
- The reason does not provide a correct explanation for the assertion, as red fibres do not primarily rely on anaerobic metabolism; they are more suited for endurance activities that require sustained energy through aerobic processes.
Key Takeaways
- Red fibres = High myoglobin content = Reddish appearance.
- Red fibres predominantly utilize aerobic metabolism, not anaerobic.
- The disconnection between the assertion and the reason confirms that option 'C' is indeed correct.
Assertion (A): Red fibres in muscles have a high content of myoglobin,...
- The Assertion is true because red fibres do indeed have a high content of myoglobin, which gives them a reddish appearance.
- The Reason is false because red fibres primarily rely on aerobic metabolism due to their high myoglobin and mitochondrial content, not anaerobic metabolism.
- Since the Assertion is true and the Reason is false, Option B is correct as both statements are true, but the Reason does not correctly explain the Assertion.
Line in NCERT: 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