Question

Identify the correct statement(s) regarding respiration:
i. Fatty acids cannot be used for respiration.
ii. The energy is used to synthesise ATP molecules.
iii. Intermediate products of respiration are used as precursors for biosynthesis of other molecules.

• A. Only i is correct
• B. Both i and ii are correct
• C. Only ii is correct
• D. Both ii and iii are correct

Answer 1

The correct option is D Both ii and iii are correct

The breakdown of C-C bonds of complex reactants via oxidation in a cell to release energy is called respiration. The compounds used for respiration are called respiratory substrates. Major source of energy is carbohydrate, however, fatty acids and amino acids can also be used under certain circumstances. Hence, statement i is incorrect.

The respiration results in the release of energy which is stored as ATP. The ATP is utilised in different metabolic processes such as active transport or biosynthesis of other molecules.

The intermediate products of respiration are used as precursors for biosynthesis of other molecules. For example, glyceraldehyde-3-phosphate is used to synthesise ribulose-1,5-bisphosphate (RuBP) during photosynthesis and acetyl-CoA is the precursor for fatty acid biosynthesis. Hence, statement ii and iii are correct.