13. Which of the following monosaccharides is not an aldose?(A)erythrose(B)fructose(C)glucose(D)glyceraldehyde(E) ribose

17. Peripheral membrane proteins:(A)are generally noncovalently bound to membrane lipids.(B)are usually denatured when released from membranes.(C)can be released from membranes only by treatment with detergent(s).(D)may have functional units on both sides of the membrane.(E) penetrate deeply into the lipid bilayer.