Cell Biology Questions

1. Provide some examples of physiological factors or conditions within the cellular (or subcellular) environment that may affect the likelihood that a biochemical reaction will take place. How do you think cells might be able to maintain or optimize conditions to favor the reaction?

2. Enzyme inhibitors are commonly used as therapeutic drugs in the treatment of a variety of human diseases (for example, cardiovascular disease, diabetes, cancer). Provide an example of a therapeutic drug, the disease it is used to treat, and include the enzyme(s) that it inhibits. Lastly, tell us what is known about how the drug inhibits the enzyme (irreversible vs reversible, competitive or non-competitive, etc.).

3. Using the textbook and/or additional resources, compare and contrast two biological membranes of your choice. The membranes can be from different cell types in the same organism (for example, nerve vs liver), two different organisms (ex. bacteria vs human), or two membranes within the same cell type (ex. nuclear membrane vs plasma membrane). Provide 2-3 properties of the two membranes that are different (think in terms of the types of proteins and lipids that make up the membrane) and then briefly describe how these properties give the membranes their unique functions.

4. Proper functioning organelles are essential for cells and organisms to remain healthy and viable. Malfunctioning organelles are responsible for a number of human diseases, including lysosomal storage disorders described in Chapter 4. Using the textbook or internet resources, find a human disease that is caused by a defect in a particular organelle. Provide some information about how the specific defect alters organelle function and ultimately causes the disease. In addition, indicate whether there are currently any therapeutic approaches to treat the disease (if none are available, what approaches do you think could be done to treat or cure the disease?).

5. Chemical inhibitors of topoisomerases, including camp tothecin and etoposide, are commonly used in the treatment of human cancers. Why do you think topoisomerase inhibitors are effective in killing cancer cells?

6. The drug chloroquine is used therapeutically to treat malaria and other conditions. One target of chloroquine in the cell is the lysosome, where it can inhibit autophagy and raise lysosome pH. What effects could lysosomal inhibition have on general cell biology? Do you think these effects are all negative, or could there also be positive effects? Why or why not?

7. The treatment of many human diseases involve drugs that inhibitor or antagonize transporters and ion channels on the cell membrane. Find an example of such a drug. Provide the name of the transporter/channel that the drug targets and the disease it is used to treat. In addition, what molecules move through this transporter/channel and in what direction? Does the movement occur via diffusion or through an active transport process?

8. Human cells contain more than 100 enzymes (GAPs, GEFs, and GDIs) that regulate the activity of Rho GTPases, which are important in actin microfilament dynamics. Why do you think cells have such a high degree of this regulation? The expression of some of these regulators are altered in cancer cells. What advantages might this altered regulation provide to a cancer cell?

9. What effects would the drug nocodazole have on the ability of the cell to transport vesicles from the ER and Golgi apparatus to the cell surface? Why?

10. Ion channel inhibitors are commonly used as drugs for the treatment of a variety of different human disease states. Find an example of such a drug and provide some information on the channel it targets and the disease state it is used to treat.

11. Various cell signaling pathways respond to growth factors (such as epidermal growth factor) to promote cellular proliferation and division, including through the activation of a Ras protein. These growth factor pathways are often de-regulated in cancer. For example, 20-30% of all tumors have mutations in a Ras protein (N-Ras, K-Ras, and H-Ras) that can cause the protein to be constitutively active. Imagine a cell in which Ras (which is normally is only activated in response to binding of a growth factor to a growth factor receptor) is permanently turned on because of a mutation. If the growth factor was withdrawn now from the cell, do you think the cell would still be able to grow? Why or why not? Next, imagine you were tasked with designing a drug to inhibit Ras signaling in this cell. What might be a good potential target?

Cell Biology Questions 1. Provide some examples of physiological...