Homework 6

Question 1

The simplest of all carbohydrates has ___ carbon atoms.

1

2

3

4

5

6

Answer 1

3

Question 2

Carbohydrates that differ at one stereocenter are called ___________.

anomers

epimers

diastereoisomers

enantiomers

Answer 2

Epimers

Question 3

A pyranose ___________, whereas a furanose ___________.

contains a five-membered ring; contains a six-membered ring

is a sugar that is present in animals; is a sugar that is present in plants

contains a six-membered ring; contains a five-membered ring

is a five-carbon sugar; is a six-carbon sugar

Answer 3

contains a six-membered ring; contains a five-membered ring

Question 4

Which of the following statements about starch and glycogen is false?

Amylose is unbranched; amylopectin and glycogen contain many branches.

Both are basic structural elements in cell walls.

Both are storage polysaccharides.

Both are homopolymers of glucose.

Answer 4

Both are basic structural elements in cell walls.

Question 5

Assume that you are working in a biochemistry laboratory and your supervisor provides you with two samples of white crystalline powder of either lactose or sucrose. Which of the following tests will you need to perform to determine the identity of each of those sugars?

Test their ability to reduce Cu2+ or Ag+. Only lactose will react.

Check their pH; lactose is more acidic than sucrose.

Solubilize both in water; while lactose is only minimally soluble, sucrose is very soluble.

Taste both; sucrose is sweeter than lactose.

Answer 5

Test their ability to reduce Cu2+ or Ag+. Only lactose will react.

Question 6

Both α(1→4) and α(1→6) bonds can be found in the plant product ________________

Answer 6

Amylopectin