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

Explanation:

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.

during the process of dna replication, brdu can replace thymidine and incorporate into the newly synthesized dna, cell proliferation thus can be reflected in the extent of brdu incorporation.