Becker's World of the Cell 9th Edition by Lewis Kleinsmith, Jeff Hardin, Gregory Paul Bertoni

Exercise 6

It's All About Membranes. Answer each of the following questions about biological membranes in 50 words or less:
(a)What is an amphipathic molecule Why are amphipathic molecules important constituents of membranes
(b)Why are membranes lipid bilayers and not monolayers
(c)What does "selectively permeable" mean
(d)If a lipid bilayer is at least 10 8 times less permeable to K + ions than it is to water, how do the K + ions that are needed for many cellular functions get into the cell
(e)It is often possible to predict the number of times a membrane protein crosses the membrane by determining how many short sequences of hydrophobic amino acids are present in the amino acid sequence of the protein. Explain.