The Energetics of Coupled Transport

Sucrose concentration is higher in the cytoplasm than in the extracellular environment. Na + concentration is higher in the extracellular environment than in the cytoplasm. Animal cells can take up sucrose against its concentration gradient using a Na+/sucrose symporter. Indicate if the following statements are true or false.

A. In the Na+/sucrose symporter, Na + is also moving against its concentration gradient.

B. For the symporter to work, the cell must first establish a Na + concentration gradient.

C. A symporter works by making the phospholipid bilayer more permeable to ions and sucrose.

D. Moving sucrose against its concentration gradient is a form of active transport.

E. A Na+/sucrose antiporter would be capable of moving sucrose into the cell while moving Na + out of the cell.

F. Since the Na+/sucrose symporter exchanges a single sucrose for a single Na+, it can also be considered a uniporter

Question

Biology

Kobe Morrow

22 September, 19:39

The Energetics of Coupled Transport

Sucrose concentration is higher in the cytoplasm than in the extracellular environment. Na + concentration is higher in the extracellular environment than in the cytoplasm. Animal cells can take up sucrose against its concentration gradient using a Na+/sucrose symporter. Indicate if the following statements are true or false.

A. In the Na+/sucrose symporter, Na + is also moving against its concentration gradient.

B. For the symporter to work, the cell must first establish a Na + concentration gradient.

C. A symporter works by making the phospholipid bilayer more permeable to ions and sucrose.

D. Moving sucrose against its concentration gradient is a form of active transport.

E. A Na+/sucrose antiporter would be capable of moving sucrose into the cell while moving Na + out of the cell.

F. Since the Na+/sucrose symporter exchanges a single sucrose for a single Na+, it can also be considered a uniporter

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Answers (1)

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Pablo Rhodes · Answer 1

A. False - A symporter system requires that one of the molecules to be transported using passive transport.

B. True - The Na + will move down the established concentration gradient releasing energy to facilitate movement of sucrose against its concentration gradient. This is known as secondary active transport.

C. False - sucrose moves through ion channels not by diffusion to better control its movement across the membrane.

D. True - Movement of molecules against their concentration gradient thus requiring energy input is known as active transport.

E. False - One of the molecules needs to be moving against its concentration gradient.

F. False - A Uniporter system allows the binding and transport of a single molecule at a time. A symporter allows simultaneous binding and transport of Na + and sucrose molecules.