When Certain Molecules Are Pumped Across Biological Membranes Against a Concentration

question 22

Multiple Choice

When certain molecules are pumped across biological membranes against a concentration gradient via active transport, ATP is used. In our body cells, 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)Overall, prokaryotes will gain more ATP per sugar molecule metabolized than will eukaryotes.
• C)Prokaryotes and eukaryotes should have the same metabolic efficiency when digesting the same sugars, assuming their enzymes are the same.
• D)Sugar metabolism in prokaryotes is exergonic, whereas in eukaryotes it is endergonic.

---

Definitions:

Variable Selling

Costs related to selling that vary with sales activity, such as sales commission.

Fixed Costs

Fixed costs are business expenses that do not change in proportion to the volume of goods or services produced or sold.

Make or Buy

A decision-making process regarding whether to produce goods in-house or purchase them from an external supplier.

Fixed Manufacturing Overhead

Indirect manufacturing costs that remain constant regardless of the level of production, such as factory rent and salaries of supervisory staff.