What are metabolic pathways catalyzed by? What are metabolic pathways determined by?

When muscle cells run out of oxygen, what happens to the potential for energy extraction from sugars and what pathways do the cell use?

The normal enzyme required for converting sugars into glucose is present in cells, but the conversion never takes place and no glucose is produced. What could have occurred to cause this defect in a metabolic pathway?

Cells expend energy on what three categories of activities?

How Art the Enzymes of Metabolic Pathways Organized? Name the four principal modes of enzyme organization in metabolic pathways.

What do enzymes do in metabolic reactions?

Explain how glucose is metabolized to yield ATP.

Figure 27.3 illustrates the response of R (ATP-regenerating) and U (ATP-utilizing) enzymes to energy charge. a. Would hexokinase be an R enzyme or a U enzyme? Would glutamine: PRPP amidotransferase, the second enzyme in purine biosynthesis, be an R enzyme or a U enzyme? b. If energy charge = 0.5: Is the activity of hexokinase high or low? Is ribose-5-P pyrophosphokinase activity high or low? c. If energy charge = 0.95: Is the activity of hexokinase high or low? Is ribose-5-P pyrophosphokinase activity high or low?

Using the answer code on the right, indicate which form of energy production is being described: 1. takes place in the mitochondrial matrix 2. produces H2O as a by-product 3. results in a rich yield of ATP 4. takes place in the cytosol 5. processes acetyl-CoA 6. takes place in the mitochondrial innermembrane cristae 7. converts glucose into two pyruvate molecules 8. uses molecular oxygen 9. accomplished by the electron transport system and ATP synthase (a) glycolysis (b) citric acid cycle (c) oxidative phosphorylation

How is a condition such as diabetes a good example of the failure of a set point in humans?