Regulation of Glycolysis and Lactate Formation

Very Hard Biochemistry Metabolism

The glycolytic pathway is a critical metabolic pathway that converts glucose into pyruvate, producing ATP and NADH in the process. In anaerobic conditions, pyruvate can be further metabolized to lactate via lactate dehydrogenase. This pathway is key to understanding the balance between fermentation and aerobic respiration.

In eukaryotic cells, particularly in muscles, the conversion of pyruvate to lactate allows for the regeneration of NAD+, which is necessary for glycolysis to continue. However, the accumulation of lactate can lead to metabolic acidosis if not adequately cleared from the bloodstream.

Which of the following statements about the regulatory roles of key enzymes in glycolysis and the conversion of pyruvate to lactate is correct?

Hexokinase is inhibited by glucose-6-phosphate, allowing for the regulation of glucose metabolism at higher concentrations of glucose.

Phosphofructokinase-1 (PFK-1) is activated by ATP and citrate, ensuring that glycolysis occurs when energy levels are high.

Pyruvate kinase is activated by fructose-1,6-bisphosphate, which serves as a feedforward activator linking earlier steps in glycolysis to its end.

Lactate dehydrogenase activity is inhibited by high levels of NADH, ensuring that lactate accumulates only when NAD+ is in sufficient supply.

Hint

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