When Certain Molecules Are Pumped Across Biological Membranes Against a Concentration

question 87

Multiple Choice

When certain molecules are pumped across biological membranes against a concentration gradient via active transport, ATP is used. In the cells of our bodies, for example, sugars are actively transported and metabolized within the membrane-enclosed mitochondria. Prokaryotes, in contrast, lack mitochondria but are nonetheless able to metabolize the same sugars. Based on the details provided in this scenario, which of the following statements is expected to be TRUE?

• A) The sugar-digesting enzymes in eukaryotic cells, such as sucrase, are not the same sugar-digesting enzymes found in prokaryotic cells.
• B) Sugar metabolism in prokaryotes is exergonic, whereas in eukaryotes it is endergonic.
• C) Prokaryotes and eukaryotes should have the same metabolic efficiency when digesting the same sugars, assuming their enzymes are the same.
• D) Overall, prokaryotes will gain more ATP per sugar molecule metabolized than will eukaryotes.

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