University:
Glendale Community College
Course:
CHM130 | Fundamental Chemistry
Academic year:

2020
Views:

163

Pages:

4
Author:

Kaleb Gentry

1 Comprehensive Worksheet 2 - Key 1. Classify the following monosaccharides, indicating the functional group and number of carbons. (For example, D-glyceraldehyde is an aldotriose.) O C H CH2OH C O HO C H H C OH H C OH CH2OH H C OH CHO HO C H HO C H H C OH HO C H aldotetrose CH2OH ketohexose CH2OH aldopentose 2. The following structure is that of α-D-galactopyranose. CH2OH HO O OH OH OH a. Draw the structure of β-D-galactopyranose. CH2OH HO O OH OH OH b. Draw 6-phospho-α-D-galactopyranose. OH O HO OH OH OH ketohexose 2 CH2OPO3 HO O 2- OH OH OH c. Draw 3-deoxy-α-D- galactopyranose. CH2OH HO O OH OH 3. The following structure is that of α-lactose, also known as milk sugar. OH OH OH O HO O O OH * HO OH OH a. Can mutarotation occur at any of the carbons? If so, circle the carbon(s). Yes – at the hemiacetal. b. What type of linkage joins the monosaccharides? (Be specific about the numbering and orientation.) β(1,4)-glycosidic bond c. Circle a hemiacetal carbon, if any. See answer to part a. 3 d. Put an asterisk by an acetal carbon, if any. e. Draw a Haworth projection of α-lactose. CH2OH O OH CH2OH HO O OH O OH OH OH 4. Draw an example of a disaccharide with a α-(1,3)-glycosidic linkage. You may draw the structure using chairs or Haworth projections. CH2OH O CH2OH HO O OH OH OH O OH OH 4 5. For the following reactions identify the class of enzyme that catalyzes it. Your choices are: oxidoreductase, transferase, hydrolase, lyase, isomerase, and ligase O O O O O ligase - - O O- O O O lyase OH O O O - - O O SCoA SCoA O O + hydrolase H2N OH N H O O isomerase OH HO O HO O OH