Question

group on the 13. In double-stranded DNA, a pyrimidine group on one strand base pairs with a other strand; the two strands are oriented in directions. a. purine, parallel b. purine, antiparallel c. pyrimidine, parallel d. pyrimidine, antiparallel Questions 14 and 15 refer to the following information: A disaccharide composed of arabinose and xylose gives arabinose and xylonic acid by reaction with Bry-water followed by hydrolysis. Reaction of its methyl glycoside with iodomethane under basic conditions followed by hydrolysis gives the products shown. Disaccharide 1. By H, 2. H,09 Arabinose Xylonic Acid CHO H,COH H OCH, нон CHOCH, Trimethy arabinose сно OH H.co+H носно CHỊCH Dimethyl- xylose 1. CH,OH, HCI - 2. CHşl, base 3. Ho 14. Which monosaccharide unit is the glycoside, and is it in its furanose or its pyranose form? a. arabinose-furanose C. xylose-furanose b. arabinose -pyranose d. xylose-pyranose 15. Which of the following describes the glycosidic bond between the monosaccharide units of the above disaccharide? a. (1-2) b. (1-4) C. (1-5) d. (2-1) e. ( 2 4) Questions 16-20 Indicate whether each of the following statements is true or false 16. The fluidity of membranes depends largely on the degree of hydrogen bonding interactions between the hydrocarbon tail groups. a. True b. False 17. The osmotic pressure of a solution does not depend on the molecular weight of the solute. a. True b. False 18. Chitin is a glycoprotein found in the exoskeletons of insects. a. True b. False 19. The two layers of biological membranes usually have different lipid compositions. a. True b. False 20. Since H2PO, has a pk, of about 7, it is considered to be a "universal buffer, that is, it can be used with its conjugate base to make effective buffers over the full range of pH O to pH 14 a. True b. False

Answer 1

Solution 13.

In a double stranded DNA, a pyramidine group on one strand base pairs with....PURINE... Group on the other strand.

Because purine pairs with pyrimidine base.

The two stands in DNA are oriented in .... Antiparallel direction...

So option B is correct.