There are two distinct models for how the Golgi network functions that scientists have yet to unravel, mainly due to the lack of evidence unique to one model or the other. What are the two models for Golgi structure and how are they similar? Now suppose you were investigating these models, what is one piece of evidence you would look for it to support one of the models.

If you did a classic Pulse-Chase experiment to follow the path of a secreted protein, and you forgot to do the Chase, which of the following would you observe?     No radioactivity would be seen in any of the structures.     Radioactivity would increase first in rough ER, then Golgi Complex, then secretory vesicles, but it would remain high in all, never decreasing.     Nothing would change     Radioactivity would increase in all 3 structures simultaneously and stay high.

"In most animal cells, minus end-directed microtubule motors deliver their cargo to the periphery of the cell, whereas plus end-directed microtubule motors deliver their cargo to the interior of the cell", is true or false.

1) Describe the role of the signal sequence and the signal recognition particle (SRP) in targeting and processing proteins in the endoplasmic reticulum. 2) What is the function of the trans-Golgi network?

A fluorescent molecule of 2000 daltons is microinjected into a single cell of an epithelial layer. When the layer is examined in a fluorescence microscope, the molecule remains confined to that cell. However, when a fluorescent molecule of 800 daltons is injected into a single cell of an epithelial layer, it quickly appears in the adjacent cells. Which of the following is responsible for the spread of the smaller molecule? 1. A) Desmosomes (maculae adherentes) 2. B) Focal contacts 3. C) Gap junctions 4. D) Intermediate junctions 5. E) Tight junctions (zonulae occludentes)

In the context of cell biology, what do we mean by form follows function? What are a least two examples of this concept?

Consider two different proteins that are leaving from the Golgi in order to arrive in their common destination, a lysosome. In order for these two different proteins to be sent to the same place, what should they have in common? A) They must have the same primary structure B) They must have been imported into the cell by endocytosis. C) They must have the same tertiary structure D) They probably have the same glycosylation pattern. ..

You are investigating a lysosomal storage disease and you discover that newly synthesized lysosome hydrolases (proteins that should be sent to the lysosome) are secreted from the cells rather than being delivered to the lysosomes (where they should normally be located). What is the most likely explanation for this finding? (Hint:  what might be different about the proteins that would cause them to not end up in the correct location?)

You are using fluorescence microscopy to study a plasma membrane protein that is fused to green fluorescent protein (GFP). Adding GFP to a protein allows us to monitor the protein in live cells using light microscopy without the need for any special stains. Under baseline conditions, the fusion protein is evenly distributed over the surface of the cell. You use the microscope software and laser to photobleach an ROI and watch for the recovery of fluorescence in real time.  you have a control protein, a GFP fusion with the insulin receptor, where the ROI fully recovers from photobleaching in 10 min. However, when Protein X is fused with GFP, the fluorescence recovers only to 10% the starting levels in 10 min in the same cell type under the same experimental conditions.  Provide two different, reasonable explanations for the different results with these two fusion proteins.

if you visualize the cytoskeleton of a cell that is expanding in one direction, you typically observed a strong orientation of the cytoskeleton. Please answer the following three questions. a. Would the cytoskeleton be oriented parallel or perpendicular to the direction of cell expansion?  b. Would the cellulose fibers in the cell wall be parallel or perpendicular to the cytoskeleton?  c. Explain why cytoskeleton, cellulose fibers, and direction of cell expansion have the relationship mentioned in a and b?