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SA1a. (5 pts) Indicate how you would expect each of the proteins listed below to be sorted: A. Kinesin motor protein that ‘walks’ along microtubules to help move vesicles throughout the cytoplasm. [answer1] B. A G-protein coupled receptor that sits on the cell’s plasma membrane to receive signals from elsewhere in the organism. [answer2] C. A neurotransmitter which is transported to the cell surface in a vesicle which gets dumped into the synaptic gap between two neurons. [answer3] D. Pyruvate dehydrogenase, a protein which gets imported into the mitochondria where it resides to perform a crucial step in cellular respiration. [answer4] E. A membrane protein located on the surface of the endoplasmic reticulum of the cell. [answer5]

SA4c. (2 pts) Nerve cells and skin cells both receive the same hormonal signal but elicit a very different downstream response.  Other types of cells may have their own response even though they all received the same signal.  List two reasons about how this can happen:

A transporter that pumps two solutes in the same direction is called a. . .

SA1b. (5 pts)  Microscopy Matching.  Match each type of microscopy with its definition. 

You have two beakers as depicted below.  Both are split in the middle and contain a semipermeable membrane. Both also contain a solute which cannot cross the semipermeable membrane by itself; the amount of solute is different on both sides of the beaker. Beaker #2 contains transporters embedded in the semi-permeable membrane that will allow the solute to pass.    You leave the beakers this way for a few hours and then come back to observe the results. What is most likely to happen?  

SA2a.  (2 pts) In the graph, do the wild-type yeast cell membranes show an increase or a decrease in fluidity with increasing temperature?  Discuss whether this is the result you would expect to see or whether it’s surprising.

This drug acts as both a stimulant and a psychedelic.  It produces an energizing effect that distorts both physical nad coginitive sensations and it may impair memory. It works by affecting a neuron’ ability to use the chemical serotonin.  It can sometimes result in too much water in the blood which can cause brain swelling.  

In the context of protein trafficking, what are  zip codes and signal sequences?

Academic Integrity Statement: I hereby declare that this exam represents my own work. I did not cheat on this exam or help others to cheat on this exam.  I did not share my answers or give help or suggestions to anyone. If I observed any cheating, I will report it to the instructor later today.  

The phosphate transport system in bacteria imports phosphate into the cell even when the concentration of phosphate outside the cell is much lower than the cytoplasmic phosphate concentration. Phosphate import depends on a pH gradient across the membrane—more acidic outside the cell than inside the cell. Phosphate transport is an example of _____.