Ques. 1AIPMT 2003
In which one of the following do the two names refer to one and same thing?
- Krebs' cycle and Calvin cycle
- Tricarboxylic acid cycle and citric acid cycle
- Citric acid cycle and Calvin cycle
- Tricarboxylic acid cycle and urea cycle
Answer
(2) Tricarboxylic acid cycle and citric acid cycle
Solution
As per NCERT, the tricarboxylic acid cycle (TCA cycle) is also called the Krebs' cycle or citric acid cycle; its first product, citric acid, is a tricarboxylic acid.
⇒ The Calvin cycle is the C3 cycle of photosynthesis and the urea cycle (ornithine cycle) forms urea in the liver; both are different pathways.
∴ Tricarboxylic acid cycle and citric acid cycle are the same.
Answer: (2)