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 Researchers believe that protein 1 and protein 2 are functioning in the same complex.  They perform a Co-immunoprecipitation (Co-IP) experiment to see if that is the case. They first immunoprecipitated with an antibody against protein 1.  Subsequently they run a western blot and treat it with an antibody targeting protein 2. The result shows a band in their positive control lane but no bands in the negative control lane or their experimental lane. What is the simplest conclusion from this experiment?

 Which of the following is characteristic of a steroid hormone action?

Which of the following crosses phospholipid bilayers most easily?

You are analyzing blood from a patient with leukemia. You are interested in counting the cells and sorting them based on the presence or absence of a particular biomarker.  Which technique should you use?

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.