Carbohydrates (2)

Question 1

Which of the following carbohydrates is associated with crustacean shells?

cellulose
chitin
glucose
glycogen

Answer 1

Chitin

Question 2

Which of the following is true of the hydrolysis of carbohydrates?

• carbohydrates cannot be hydrolyzed
• hydrolysis of carbohydrates can only yield polyhydroxyaldehydes
• hydrolysis of carbohydrates can only yield polyhydroxyetenes
• hydrolysis of carbohydrates can yield polyhydroxyaldehydes and/or polyhydroxyketones

Answer 2

hydrolysis of carbohydrates can yield polyhydroxyaldehydes and/or polyhydroxyketones

Question 3

How many chiral carbons are present in the open-chain chain (Fischer) form of galactose?

-3 -4 -5 -6

Answer 3

4

Question 4

which of the following ours when a monosaccharide is converted to an amino sugar?

• an amino group replaces an aldehyde carbonyl
• amino group replaces a ketone carbonyl
• an amino group replaces a hydroxyl group
• any of the above, depends on the identity of the monosaccharide

Answer 4

an amino group replaces a hydroxyl group

Question 5

The cyclic structures of monosaccharides are which of the following?

• acetals
• hemiacetals
• ethers
• esters

Answer 5

hemiacetals

Question 6

When fructose adopts a cyclic (Haworth form), it will have a ___ structure.

• Pyranose
• furanose
• ketose
• hexose

Answer 6

furanose

Question 7

The OH group attached to the ___ chiral carbon from the carbonyl group is used to determine D or L isomer

• closest
• middle
• farthest
• first

Answer 7

farthest

Question 8

Which of the following is true of the spatial distribution of the hydroxyl groups of n-D-glucopyranose?

• they are all in axial positions
• they are all in equatorial positions
• the hydroxyl on C1, those on C2, C-3, and C3 are equatorial
• the hydroxyl on C-1 is equatorial, those on C2, C3 and C4 are axial

Answer 8

the hydroxyl on C1, those on C2, C-3, and C3 are equatorial

Question 9

Which of the following reacts with sugars to form glycosides?

• alcohol
• amines
  -hemiacetals
• water

Answer 9

alcohol

Question 10

Glycosides are example of which class of compounds?

• acetals
• hemiacetals
• esters
• ethers

Answer 10

ethers

Question 11

Which of the following explains why glycosides do not undergo mutarotation?

• there is no longer an anomeric carbon
• there are no longer any stereocenters
• the ring carbon does not open to become rinh structure
• none of the above

Answer 11

the ring carbon does not open to become rinh structure

Question 12

An alpha(1->4) glycosidic bond can be seen from the following

• lactose
• maltose
• sucrose
• all of the above

Answer 12

maltose

Question 13

Which of the following determines blood type A in the ABO blood typing system?

• the presenve of only N-acetyl-D-galactosamine antigen
• the presence of only D-galactose antigen
• the presence of both N-acetyl-D-galactosamine antigen and D-galactose antigen
• the absence of both N-acetyl-D-galactosamine antigen and D-galactose antigen

Answer 13

the presence of only N-acetyl-D-galactosamine antigen

Question 14

Which of the following is obtained as a result of the complete hydrolysis of starch?

• D-glucose
• maltose
• lactose
• sucrose

Answer 14

D-glucose

Question 15

Which of the following is true of amylopectin?

• it consists of as many as 4000 D-glucose units linearly linked by ALPHA (1->4) glycosidic bonds.
• it consists of as many as 4000 D-glucose units linearly linked by BETA(1->4) glycosidic bonds.
• it consists of as many as 4000 D-glucose units linearly linked by ALPHA(1->4) glycosidic bonds. and there are branches every 24-30 units via ALPHA (1->6) glycosidic bonds
• it consists of as many as 4000 D-glucose units linearly linked by BETA(1->4) glycosidic bonds. and there are branches every 24-30 units via BETA(1->6) glycosidic bonds

Answer 15

it consists of as many as 4000 D-glucose units linearly linked by ALPHA(1->4) glycosidic bonds. and there are branches every 24-30 units via ALPHA (1->6) glycosidic bonds

Question 16

Glycogen is structurally similar to which of the following?

• amylopectin
• amylose
• cellulose
• none of these

Answer 16

amylopectin

Question 17

In hyaluronic acid, how is D-glucuronic acid linked to N-acetyl-D-glucosamine?

• by an ALPHA(1->3) glycosidic bond
• by an ALPHA(1->4) glycosidic bond
• by a BETA(1->3) glycosidic bond
• by a BETA(1->4) glycosidic bond

Answer 17

by a BETA(1->3) glycosidic bond

Question 18

What other monosaccharides combines with glucose to form lactose?

• glucose
• mannose
• galactose
• fructose

Answer 18

galactose

Question 19

Epimers are ____.

• stereoisomers that differ from each other in their configuration at a single carbon atom.
• stereoisomers that differ from each other in their configuration at a single carbon atom.
• the ALPHA and BETA forms of cyclic sugars
• two related compounds, pyran, and furan

Answer 19

stereoisomers that differ from each other in their configuration at a single carbon atom.

Question 20

Which of the following is a nonreducing disaccharide?

• mannose
• maltose
• sucrose
• lactose

Answer 20

sucrose

Question 21

Which of the following types of bonds holds one monosaccharide to the next one in a polysaccharide?

• glycosidic
• carbonyl
• diol
• ester

Answer 21

glycosidic

Question 22

What heteropolysaccharide is a component of cartilage and may relieve symptoms of osteoarthritis?

• chondroitin sulfate
• hyaluronic acid
• heparin
• D-glucosamine

Answer 22

chondroitin sulfate

Question 23

The only true sugar that does not contain a chiral carbon atom

• dihydroxyacetone
• glyceraldehyde
• ribose
• glycosaminoglycans

Answer 23

glyceraldehyde

Question 24

Which group of glycoconjugates is generally used for metabolic transport, intercellular communication, regulation, and catalysis?

• proteoglycans
• glycoproteins
• glycolipids
• glycosaminoglycans

Answer 24

glycoproteins

Question 25

Sugars, which differ only around only one carbon atom, are properly called __. - anomers - diastereoisomers - enantiomers - epimers

Answer 25

epimers