Question

Krebs’ cycle takes place in
a) Cytoplasm
b) Chloroplast
c) Nucleus
d) Mitochondria

Answer 1

Hint: Krebs cycle is also known as the citric acid cycle. It is used in the energy formation by the aerobic process of respiration. In this oxidation of acetyl, CoA takes place which is derived from the carbohydrates.

Complete step by step answer:
The Krebs cycle takes place in the mitochondria of the cell. The inner membrane of mitochondria surrounds the mitochondrial matrix where the process of the citric acid cycle or Krebs cycle takes place. The mitochondrial matrix is located inside the inner membrane. The enzyme present in the matrix helps in the production of ATP by facilitating the citric acid cycle and oxidative phosphorylation. The citric acid cycle is a cycle that involves a series of reduction, oxidation, dehydration, hydration, and decarboxylation. Each turn of the cycle forms an ATP and three NADH molecules and a FADH molecule. Acetyl CoA combines with the oxaloacetate to form citrate. Citrate is converted to the isocitrate, which is then oxidized to the alpha-ketoglutarate. This molecule is then oxidized to form succinyl CoA and a molecule of NADH is released in the process along with a molecule of carbon dioxide. Succinyl CoA is then converted to succinate which is further converted to fumarate. Fumarate gets converted into malate and then to oxaloacetate. During the process, another molecule of NADH is released.

So, the answer is ‘mitochondria’.

Note:
Mitochondria is the membrane-bound organelle. Mitochondria is the powerhouse of the cell. It is used in the production of ATP molecules which are used for the energy production in the cell. It generates the chemical energy of the cell.