Biochemistry of Carbohydrates

Question 1

Molecules that occur naturally in living organisms are?

Answer 1

Biomolecules

Question 2

The four main types of BIOMOLECULES are?

Answer 2

Carbohydrates
Proteins
Nucleic acids
Lipids

Question 3

The bond mostly found in biomolecules is?

Answer 3

Covalent bond

Question 4

BIOMOLECULES consists of?

Answer 4

Carbon
Hydrogen
Nitrogen
Phosphorus
Oxygen
Sulphur

Question 5

Some functions of carbohydrates are?

Answer 5

They serve as structural component of cell membrane

They serve as a source of fuel and energy

Question 6

The general molecular formula of carbohydrates are?

Answer 6

(CH2O)n

where n>3

Question 7

Carbohydrates are_____ or compounds which give these substances on hydrolysis

Answer 7

Polyhydroxy aldehydes or ketones

Question 8

The three major classes of carbohydrates are?

Answer 8

Monosaccharides
Oligosaccharides
Polysaccharides

Question 9

Monosaccharides are also called?

Answer 9

Simple sugars

Question 10

Monosaccharides consist of?

Answer 10

3-7 carbon atoms

Single polyhydroxy aldehyde or ketone unit

Question 11

Most abundant monosaccharides are the?

Answer 11

6 carbon sugars

Question 12

Example of 6 carbon sugars are?

Answer 12

D-glucose

Fructose

Question 13

The monosaccharide structure consists of?

Answer 13

Unbranched, single bonded carbon chain backbone

1 carbon atom attached to an oxygen atom by double bond

Question 14

The 2 families of monosaccharides are?

Answer 14

Aldoses

Ketoses

Question 15

Monosaccharides containing aldehydes are called?

Answer 15

Aldoses

Question 16

Monosaccharides containing ketones are called?

Answer 16

Ketoses

Question 17

When a carbohydrate reacts, mostly the ___ reacts

Answer 17

OH ion

Question 18

Molecules with more than one OH group either at the terminal carbon atom(aldose) or second carbon atom (ketose) are called?

Answer 18

Polyhydroxy aldehydes or ketones

Question 19

The change in optical rotation because of the change in equilibrium between 2 anomers when their corresponding stereo centers interconvert is called?

Answer 19

Mutarotation

Question 20

Some physical properties of monosaccharides are?

Answer 20

Colourless, crystalline compounds
Soluble in water.
Optically active solutions
Exhibit mutarotation

Question 21

A carbon that has four different groups or atoms attached to it and has optical activity in solution is called?

Answer 21

Asymmetric or chiral carbon

Question 22

The designation of a sugar isomer as the D- or L- form is determined by?

Answer 22

The spatial relationship to the parent compound of the carbohydrate family

Question 23

D- means?

Answer 23

Dexter(right) or dextrorotatory (+)

Question 24

L- means

Answer 24

Laevus(left)

Levorotatory (-)

Question 25

A mixture that has equal amounts of D and L isomers, with no optical activity is called?

Answer 25

Racemic or DL mixture

Question 26

Sugars that differ from one another, only in configuration around one carbon atom or carbohydrates which vary in one position for the placement of the -OH group are called?

Answer 26

Epimers

Question 27

A sugar whose anomeric carbon is attached to a hydroxyl group that can reduce compounds is called?

Answer 27

Reducing sugar eg maltose & lactose

Question 28

A sugar whose anomeric carbon is not attached to a hydroxyl group that can reduce compounds is called?

Answer 28

Non-reducing sugar eg sucrose

Question 29

Either of a pair of chemical compounds whose molecular structures have a non-superimposable mirror-image relationship to each other is called?

Answer 29

An enantiomer

Question 30

A mixture of equal quantities of two enantiomers, or substances that have dissymmetric molecular structures that are mirror images of one another is called?

Answer 30

Racemic mixture, also called racemate

Question 31

The main difference between anomers and epimers is that anomers differ from each other in its structure at their ___1___whereas epimers differ from each other at any one of the ___2____ present in their structure

Answer 31

1. anomeric carbon | 2. Chiral carbons

Question 32

Carbohydrates that differ from each other in its structure at their anomeric carbon are called?

Answer 32

Anomers

Question 33

An anomeric carbon may be a?

Answer 33

Hemiacetal or Hemiketal carbon

Question 34

A carbon that is attached to four different types of atoms or groups of atoms is called?

Answer 34

Chiral carbon (asymmetric carbon)

Question 35

A carbon derived from the carbonyl carbon (the ketone or aldehyde functional group) of the open-chain form of the carbohydrate molecule is called?

Answer 35

Anomeric carbon

Question 36

Carbohydrates that are stereoisomer compounds with molecules that are not mirrored images of one another and are not superimposable are called?

Answer 36

Diastereomers

Question 37

Diastereomers have different?

Answer 37

Physical properties

Question 38

An aldehyde reacts with an alcohol to form a?

Answer 38

Hemiacetal or acetal ring

Question 39

An ketone reacts with an alcohol to form a?

Answer 39

Hemiketal or metal ring