Botany - Respiration in Plants Question with Solution | TestHub

Glucose is the commonest substrate for respiration. All types of carbohydrates are first converted into glucose, which then enters the respiratory pathway i.e. Glycolysis. Similarly, proteins and fats, too, can join the path but not directly. Fats first breaks down into fatty acids and glycerol. Fatty acids can enter the respiratory pathway only if it breaks down into acetyl Co-A while glycerol will form PGAL (Phosphoglyceraldehyde) to enter the path. Thus both the products of fat metabolism can enter the respiratory pathway. Proteins breakdown into amino acids and these enter the Kreb's cycle at different stages too.