Question

Which is false?

A) fatty acids can enter Krebs cycle through a process called beta-oxidation
B) ATP can inhibit the enzyme phosphofructokinase
C) Too much NADH can inhibit pyruvate decarboxylase
D) DNA is often broken down to enter Krebs Cycle

Answer 1

D) DNA is often broken down to enter Krebs Cycle

Step-by-step explanation:

A) is true. Beta-oxidation is a process whereby fatty acids serves as precursor for cellular respiration. It is the catabolism (metabolic breakdown) of fatty acids into ACETYL coA, NADH and FADH2 molecules, which enters the Kreb's cycle to continue the process of cellular respiration.

B) is true. Phosphofructokinase is an enzyme that catalyses the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate in glycolysis. However, phosphofructokinase enzyme has been shown to be allosterically inhibited by ATP and citrate by reducing its ability to bind to its substrate (fructose-6-phosphate).

C) is true. Pyruvate dehydrogenase is a complex of enzymes that catalyzes the oxidation of pyruvate into ACETYL coA. This oxidation of pyruvate produces C02, acetyl coA and NADH molecules. Hence, the Pyruvate dehydrogenase complex can be inhibited by its own product (NADH) if produced in excessive amount.

D) is false because Deoxyribose nucleic acid (DNA) is never broken down to enter the Kreb's cycle. DNA is a nucleic acid strictly for the storage of genetic information in a cell. It has no business with cellular respiration.