Energy Metabolism I: An introduction

Sir Hans Adolf Krebs is most famous for

• a.discovering that glucose was a main source of fuel in animals.
• b.discovering the glycolysis pathway.
• c.inventing the manometer.
• d.discovering the main biochemical pathway by which cells break down food for energy.

Which is true of enzymes?

• a.Enzymes break down chemical compounds.
• b.Enzymes work in an assembly line fashion.
• c.Enzymes build up new molecules from simpler compounds.
• d.All of the answers are true.

Any enzyme can break down any chemical compound.

• a.true
• b.false

Energy metabolism

• a.occurs in the mitochondria of cells.
• b.proceeds in a straightforward linear fashion.
• c.does not require enzymes.
• d.bypasses the Krebs cycle.

Heinrich Warburg is credited with

• a.figuring out the steps of the glycolysis pathway.
• b.discovering the citric acid cycle.
• c.inventing the manometer.
• d.discovering the urea cycle.

When Hans Adolf Krebs and Kurt Henseleit discovered the urea cycle, it was clear that the pathway from ammonia to urea was a cycle because

• a.ornithine was recreated.
• b.no amino acids were involved in the process.
• c.the process bypassed the liver.
• d.ammonia levels continue to build up in the body.

Glycolysis is a biological process that

• a.builds glucose molecules from smaller pyruvate molecules.
• b.splits one glucose molecule into two pyruvate molecules.
• c.requires oxygen.
• d.does not require enzymes.

When no oxygen is available, pyruvate is converted to

• a.lactic acid.
• b.muscle cells.
• c.glucose.
• d.oxygen.

Which of the following is NOT true of the Krebs Cycle?

• a.Acetate is the needed substrate to allow the Krebs cycle to proceed.
• b.Citrate stays in the same molecular form throughout the entire cycle.
• c.Co-enzyme A (Co-A) performs a key role as a carrier molecule that escorts the tiny acetate molecule around the cell.
• d.Some of the carbon that is freed in the process forms CO₂.

Our cells most commonly store energy in the form of

• a.glucose.
• b.enzymes.
• c.ATP.
• d.GTP.