Metabolism Problem Set

The Biology Project: Biochemistry

Metabolism Problem Set

Problem 12: Hexokinase

In the first step of glycolysis, the enzyme hexokinase uses ATP to transfer a phosphate to glucose to form glucose-6-phosphate. The product continues to be oxidized forming pyryvate in glycolysis and is a precursor to acetyl-CoA for the citric acid cycle. Suppose that a cell has only glucose available for energy and that the activity of hexokinase is suddenly stopped in this cell. Which of the following conditions will occur?

A. The cell will continue to produce energy from mitochondrial electron transport
B. The cell will continue to produce ATP using the citric acid cycle.
C. The cell will ultimately be unable to produce ATP

Because energy production requires that glucose first be metabolized in glycolysis, the loss of hexokinase would block ATP production in the cell.

D. The cell will be forced to switch to fermentation to produce ATP.
E. The use of oxygen by the cell will increase.