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.

before it leaves the nucleus of a eukaryotic cell, mrna is altered in the following ways: - a cap is added to the 5' end of the mrna molecule; - a poly a tail is added to the 3' end; - introns are removed and exons are spliced together.

hammurabi rulers

good lesson