22. Carbohydrate Metabolism

How is aerobic respiration different from anaerobic respiration?

Select statement that explains importance of conversion of NADH to NAD⁺ during anaerobic respiration.

Circle the correct type of respiration under which:

a) Pyruvate converted to lactate (aerobic or anaerobic)

b) Glucose converted to pyruvate (aerobic or anaerobic)

c) Pyruvate converted to Acetyl CoA (aerobic or anaerobic)

d) Pyruvate converted to ethanol (aerobic or anaerobic)

In alcoholic fermentation, each mole of pyruvate is converted to one mole of carbon dioxide and one mole of ethanol. In the process, about 50 kcal/mol (209 kJ/mol) of energy is produced. Under the most favorable conditions, more than one-half of this energy is stored as ATP.

a. What happens to the remaining energy produced in alcoholic fermentation?

Outline the conditions that direct pyruvate toward the following:

b. Conversion to ethanol and CO₂

In what tissues or organisms is each pathway present?

Outline the conditions that direct pyruvate toward the following:

c. Conversion to lactate

In what tissues or organisms is each pathway present?

What three products are formed from pyruvate under aerobic, anaerobic, and fermentation conditions?

Which of the following conversions would you expect to consume energy and which would you expect to yield energy based on the final oxidation state of the coenzymes involved in each reaction?

a. pyruvate → lactate

Why is it important for the cell that the NADH produced when pyruvate is converted to lactate be converted back to NAD⁺?

How does the formation of lactate permit glycolysis to continue under anaerobic conditions?

When is pyruvate converted to lactate in the body?

The formation of lactate permits glycolysis to continue under anaerobic conditions. Explain.

List the energy yield in ATP molecules for each of the following:

c. Glucose → 2 lactate

Name the coenzyme produced during the conversion of pyruvate to acetyl CoA.

How and where does sucrose undergo digestion in the body? Name the products.