1) indicate true or false if the statement is false please explain why A) The pl
ID: 188497 • Letter: 1
Question
1) indicate true or false if the statement is false please explain why A) The plasma membrane is highly impermeable to all charged molecules B) transport by transporters can be either active or passive whereas transport by channels is always passive2) Ran GTPase A) Why is Ran-GTP concentrated in the nucleus? why is Ran-GDP concentrated in the cytoplasm 1) Indicate true or false (T/F)? If a statement is false, please explain why The plasma membrane is highly impermeable to all charged molecules. Transport by transporters can be either active or passive, whereas transport by channel is always passive. 2) Ran GTPase 1. Why is Ran-GTP concentrated in the nucleus? Why is Ran-GDP concentrated in the cytoplasm? 2. Explain how the concentration gradients of Ran-GTP and Ran-GDP ensure unidirectional transport of proteins into the nucleus.
Explanation / Answer
1)A) False: The membrane contains transport proteins that help some charged molecules pass through, a pure bilayer would be impermeable.
b) True. Transporters bind specific molecules and undergo a series of conformational changes to move the bound molecule across a membrane. They can transport passively down the electrochemical gradient, or the transporters can link the conformational changes to a source of metabolic energy such as ATP hydrolysis to drive active transport.
By contrast, channels form aqueous pores that can be open or shut, but always transport downhill; that is, passively. Channels interact much more weakly with the solute to be transported, and they do not undergo conformational changes to accomplish transport. As a consequence, transport through channels cannot be linked to an energy source and is always passive.
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