Question

Two names referring to the same thing are –
A) Krebs Cycle and Calvin Cycle
B) Tricarboxylic Acid Cycle and Citric Acid Cycle
C) Citric Acid Cycle and Calvin Cycle
D) Tricarboxylic Acid Cycle and Urea Cycle

Answer 1

Hint: All the chemical and biological processes taking place within the living organisms are referred to as the biochemical reactions. Sum total of all the biochemical reactions taking place within the living system is ultimately referred to as the metabolism.

Complete Answer:
Option a: Krebs cycle- This is a biochemical reaction in aerobic organisms where the acetyl-CoA undergoes the process of oxidation to release stored energy.
Calvin cycle- It is a light-independent biochemical reaction or photosynthetic carbon reduction cycle associated with the process of photosynthesis where carbon dioxide and other reactionary intermediates are converted to glucose. As these are two completely different processes. Therefore, this is the incorrect answer.

Option b: Krebs cycle is a biochemical reaction in aerobic organisms where the acetyl-CoA undergoes the process of oxidation to release stored energy. This is also known as the citric acid cycle or the tricarboxylic acid cycle. Acetyl-CoA is the first tricarboxylic acid of the Krebs cycle hence the name tricarboxylic acid cycle and as OAA converts to citrate it is also known as citrate cycle. Therefore, this is the correct answer.

Option c: Citric acid cycle is the conversion of OAA to citrate and calvin cycle is a light-independent biochemical reaction or photosynthetic carbon reduction cycle associated with the process of photosynthesis where carbon dioxide and other reactionary intermediates are converted to glucose. As these are two completely different processes. Therefore, this is the incorrect answer.

Option d: As Acetyl-CoA is formed as the first acid, the cycle is called tricarboxylic cycle. The urea cycle or the ornithine cycle is a set of biochemical reactions that utilizes ammonia to produce urea.
  As these are two completely different processes. Therefore, this is the incorrect answer.

Hence the correct answer is option ‘B’.

Note: Tricarboxylic acid cycle or the citric acid cycle or the Krebs cycle takes place within the mitochondrial matrix of the cell. The end product of Krebs cycle is 2 GTP, 6 NADH and 4 carbon dioxide.