Respiratory Substrates and Carbohydrates — NEET Biology

Which of the following statements are NOT correct regarding respiratory substrates and the respiratory pathway? S1: Only carbohydrates are oxidized to release energy in higher organisms, making them the exclusive respiratory substrates under all conditions. S2: Fats are broken down into glycerol and fatty acids, with glycerol entering the pathway after being converted to PGAL, and fatty acids degraded to acetyl CoA. S3: Amino acids, after deamination, primarily enter the respiratory pathway as intermediates of glycolysis, specifically 3-phosphoglyceraldehyde. S4: The respiratory pathway is considered purely a catabolic process because it involves the breakdown of complex organic substances, with no role in the synthesis of other compounds. S5: Organic acids can be used as respiratory substrates by plants under specific conditions, indicating flexibility in substrate utilization.