NEETBotanyRespiration in Plants
A particular respiratory substrate yields a Respiratory Quotient (RQ) of approximately 0.7 . Which of the following statements correctly describes how this substrate, or its components, enter the respiratory pathway?
Options
- AIt is degraded by proteases into amino acids, which then enter the pathway as pyruvate or acetyl CoA.
- BThe intact molecule directly enters the Krebs cycle without undergoing any prior enzymatic breakdown.
- CUpon breakdown, its fatty acid components enter the pathway as PGAL, while glycerol enters as acetyl CoA.
- DIt breaks down into fatty acids and glycerol, where fatty acids enter as acetyl CoA and glycerol enters as PGA
Correct answer
D. It breaks down into fatty acids and glycerol, where fatty acids enter as acetyl CoA and glycerol enters as PGA
Step-by-step solution
An RQ value of approximately 0.7 indicates that the respiratory substrate is a fat (e.g., tripalmitin). According to the amphibolic pathway described in NCERT, fats do not enter the respiratory pathway directly. They must first be broken down into fatty acids and glycerol. If fatty acids are to be respired, they are degraded to acetyl CoA and then enter the pathway. Glycerol enters the pathway after being converted to PGAL (Phosphoglyceraldehyde). Option 1 incorrectly describes the breakdown of proteins (which have