8. Respiration

Fill in the blanks in this summary map to help you review the key concepts of cellular respiration.

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After glucose is fully oxidized by glycolysis, pyruvate processing, and the citric acid cycle, where is most of its energy stored?

Most of the CO₂ from cellular respiration is released during

a. Stage 1: Glycolysis

b. Stage 2: Pyruvate oxidation

c. Stage 2: The citric acid cycle

d. Stage 3: Oxidative phosphorylation

Which of the following is the most immediate source of energy for making most of the ATP in your cells?

a. The transfer of from intermediate substrates to ADP

b. The movement of H⁺ across a membrane down its concentration gradient

c. The splitting of glucose into two molecules of pyruvate

d. Electrons moving through the electron transport chain

Most CO₂ from catabolism is released during

a. Glycolysis.

b. The citric acid cycle.

c. Lactate fermentation.

d. Electron transport.

Most of the energy in an ATP molecule is released ________.

a. During cellular respiration.

b. When the terminal phosphate group is hydrolyzed.

c. In the form of new nucleotides.

d. When it is transferred to NADH.

Early estimates suggested that the oxidation of glucose via aerobic respiration would produce 38 ATP. Based on what you know of the theoretical yields of ATP from cellular respiration, show how this total was determined. Why do biologists now think this amount of ATP per molecule of glucose is not achieved in cells?