4.17–4.18
4.17–There are alternative pathways to energy acquisition

Organisms can generate ATP when oxygen is lacking or when organic molecules other than glucose, such as lipids, proteins, and polysaccharides, are consumed.

Q

Which of the following energy-generating processes is the only one that occurs in all living organisms?

  • a) the Krebs cycle
  • b) glycolysis
  • c) combustion
  • d) photosynthesis
  • e) None of the above. There are no energy-generating processes that occur in all living organisms.

During the Krebs cycle:

  • a) the products of glycolysis are further broken down, generating additional ATP and the high-energy electron carrier NADH.
  • b) high-energy electron carriers pass their energy to molecules of sugar, which store the electrons as potential energy.
  • c) the products of glycolysis are broken down, generating ATP and ethanol.
  • d) cellular respiration can continue even in the absence of oxygen.
  • e) the products of glycolysis are converted to acetyl-CoA.

All alcoholic beverages are produced as the result of:

  • a) cellular respiration by bacteria that occurs in the absence of oxygen.
  • b) cellular respiration by bacteria that occurs in the absence of free electrons.
  • c) cellular respiration by yeast that occurs in the absence of free electrons.
  • d) cellular respiration that occurs in the absence of sugar.
  • e) cellular respiration by yeast that occurs in the absence of oxygen.

In harvesting the chemical energy of the molecules in food:

  • a) all macromolecules must first be converted to glucose.
  • b) all macromolecules must first be converted to hydrocarbon chains.
  • c) all macromolecules must first be converted to simple sugars.
  • d) organisms can use sugars, lipids, and proteins.
  • e) all macromolecules must first be converted to free-form amino acids.