Problem 1: Think carefully about the chemistry of the plasma membrane, then answer this question: Why is minor damage to the membrane usually not a problem?
Problem 2: Knowing that diffusion rate is inversely proportional to molecular weight, predict the results of the following experiment: Cotton balls are simultaneously inserted in opposite ends of a one-meter-long glass tube. One cotton ball is saturated with ammonium hydroxide (NH,OH), the other with sulfuric acid (H2SO,). The two gases diffuse until they meet, at which point a white precipitate of ammonium chloride is formed. At what relative point along the tube does the precipitate form?
Problem 3: The upper layers of the skin constantly slough off. Predict the changes in the integrity of desmosomes as skin cells age (and move closer to the skin's surface).
Problem 4: Some cells produce lipid-soluble products. Can you deduce how such products are stored, that is, prevented from exiting the cell?
Problem 5: List three examples of folding of cellular membranes to increase membrane surface area.
Problem 6. Should the existence of mitochondrial ribosomes come as a complete surprise? Explain your response.
Problem 7: If a structure (such as the lens and cornea of the eye) contains no blood vessels (that is, is avascular), is it likely to be very thick? Why or why not?