Exam 8: Transport Across Membranes: Overcoming the Permeability Barrier

Because the procedure you are using to modify plants requires their cell membranes to be pulled away from the cell walls by plasmolysis,you place the cells in a(n)

The graph below shows the concentrations of B and C inside the cell over time when the cell that has imported B and C in Figure 8.1 above is transferred to a solution containing a much lower concentration of B and C.Based on these data and coupled with the data observed above,substance C is transported via

When erythrocytes are in the capillaries of body tissues,CO₂ diffuses ________ and is converted to ________.

Different ABC transporters can transport

Urea is a small molecule that is transported out of most cells by passive diffusion,but some cells,including kidney cells,have urea-facilitated transporters.Given an assay to measure the amount of urea on one side of the cell plasma,design an experiment to distinguish which mechanism an uncharacterized cell you have isolated uses to transport urea.Include graphs,if this aids in your discussion.

When Peter Agre and colleagues compared frog oocytes expressing aquaporin with control oocytes lacking aquaporin placed in pure water,they found that

Transmembrane movement of a substance down a concentration gradient with no involvement of membrane proteins is called ________.

All of the following are active transporters except

In carrier protein function kinetics,K_m is the

The energy necessary to drive the bacteriorhodopsin proton pump that creates the proton gradient needed for ATP synthesis is generated by

The erythrocyte anion exchange protein "ping-pong" transport mechanism involves

Consider a nerve cell with an internal Cl^- concentration of 50 mM,a membrane potential of 60 mV and an external Cl^- concentration of 100 mM.Each of the following is true for Cl^- import into the cell except

Transmembrane movement of a substance down a concentration gradient by a membrane protein is called ________.

Active transport makes it possible for cells to

Which of the following types of transport occur across the erythrocyte membrane?

The outer membranes of bacteria,mitochondria,and chloroplasts contain large nonselective channels made of multipass proteins known as ________ in which the transmembrane segment of the protein is composed of a ________.

Consider an erythrocyte with an internal glucose concentration of 0.1 mM and an external glucose concentration of 5 mM.Each of the following is true about GLUT1 transport of glucose across the plasma membrane into the cell except

Which of the following is true for the mechanism of the 2Na⁺/glucose symporter?