Chapter 4: Carbohydrate Structure and Function

Question 1

The simplest monosaccharides contain 3 carbon atoms and are called __________.

Answer 1

Triose

Question 2

Carbohydrates with 4, 5, and 6 carbon atoms are called ___________, __________, and ____________, respectively.

Answer 2

• Tetrose
• Pentose
• Hexose

Question 3

The simplest aldose (aldehyde sugar) is _______________ and the simplest ketose (ketone sugar) is ________________.

Answer 3

• Glyceraldehyde
• Dihydroxyacetone

Question 4

______________, also called ________________, are compounds that have the same chemical formula; these molecules differ from one another only in terms of the spatial arrangement off their component atoms.

Answer 4

• Optical isomers
• Stereoisomers

Question 5

A special type of isomerism exists between stereoisomers that are nonidentical, nonsuperimposable mirror images of each other. These molecules are called ________________.

Answer 5

Enantiomers

Question 6

When trying to figure out how many possible stereoisomers can exist for a multi-carbon compound, identify the number of ______________ (n) and plug into the formula 2^n.

Answer 6

Chiral carbons

Question 7

3 types of stereoisomers:
- The same sugars, in different optical families, are ___________________ (such as D-glucose and L-glucose)

Answer 7

Enantiomers

Question 8

3 types of stereoisomers:
- Two sugars that are in the same family (both are either ketoses or aldoses, and have the same number of carbons) that are not identical and are not mirror images of each other are _______________.

Answer 8

Diastereomers

Question 9

3 types of stereoisomers:
- A special subtype of diastereomers are those that differ in configuration at exactly one chiral centre. These are defined as ___________ (such as D-ribose and D-arabinose, which only differ at C-2)

Answer 9

Epimers

Question 10

Because the substituents on the single bond between C-1 and C-2 can rotate freely, either the alpha or beta-anomer can be formed. This spontaneous change of configuration about C-1 is known as ________________, and occurs more rapidly when the reaction is catalyzed with an acid or base.

Answer 10

Mutarotation

Question 11

Any monosaccharide with a hemiacetal ring is considered a ______________.

Answer 11

Reducing sugar

Question 12

________________ refers to the rearrangement of bonds in a compound, usually by moving a hydrogen and forming a double bond.

Answer 12

Tautomerization

Question 13

Because carbohydrates have hydroxyl groups, they are able to participate in reactions with carboxylic acids and carboxylic acid derivatives to form _________.

Answer 13

Esters

Question 14

Disaccharides and polysaccharides form as a result of ____________ bonds between monosaccharides.

Answer 14

Glycosidic bonds

Question 15

A polysaccharide composed entirely of glucose (or any other monosaccharide) is referred to as a ___________________.

Answer 15

Homopolysaccharide

Question 16

A polymer made up of more than one type of monosaccharide is considered a ____________________.

Answer 16

Heteropolysaccharide

Question 17

Cellulose, starch, and glycogen are all polysaccharides composed of the same monosaccharide, _______________.

Answer 17

D-glucose

Question 18

_____________ is the main structural component of plants. The homopolysaccharide is a chain of beta-d-glucose molecules linked by beta-1,4 glycosidic bonds, with hydrogen bonds holding the actual polymer chains together for support.

Answer 18

Cellulose

Question 19

____________ are polysaccharides that are more digestible by humans because they are linked via alpha-d-glucose-1,4 glycosidic bonds.

Answer 19

Starches

Question 20

Amyloose is degraded by ______________ and ______________.

Answer 20

• Alpha-amylase
• Beta-amylase

Question 21

_____________ cleaves amylose at the nonreducing end oof the polymer (the end with acetal) to yield maltose.

Answer 21

Beta-amylase

Question 22

_____________ cleaves randomly along the chain to yield shorter polysaccharide chains, maltose and glucose.

Answer 22

Alpha-amylase

Question 23

_____________ is a carbohydrate storage unit in animals. It has alpha-d-glucose-1,6 glycosidic bonds (approximately one for every 10 glucose molecules), which makes it a highly branched compound.

Answer 23

Glycogen

Question 24

__________________ functions by cleaving glucose from glycogen from the nonreducing end of the glycogen branch and phosphorylating it, thereby producing glucose-1-phosphate, which plays an important role in metabolism.

Answer 24

Glycogen phosphorylase

Question 25

___________ is a disaccharide made up of glucose-alpha-1,2-fructose.

Answer 25

Sucrose

Question 26

___________ is a disaccharide made up of galactose-beta-1,4-glucose.

Answer 26

Lactose

Question 27

___________ is made up of glucose-alpha-1,4-glucose.

Answer 27

Maltose