Question

Which of the following biomolecules is common to respiration-mediated breakdown of fats, carbohydrates and proteins?

• A. Pyruvic acid
• B. Acetyl CoA
• C. Fructose 1,6-bisphosphate
• D. Glucose-6-phosphate

Answer 1

Answer: (B)

During the respiratory breakdown of glucose, it first enters the glycolytic pathway in which it is first broken down into pyruvic acid by glycolysis in the cytoplasm. It then enters the mitochondria where pyruvic acid is broken down into acetyl CoA. Fats are stored in our body in the form of triglycerides which are made up of fatty acids. These fatty acids undergo a series of reactions called beta oxidation to form keto acids which get converted into acetyl CoA and can enter Krebs cycle. Amino acids which form the breakdown product of proteins form one or the other intermediates of Krebs cycle and enter into it. For example, amino acid isoleucine gets converted into acetyl CoA and enters Krebs cycle.