Carbohydrates

Question 1

A carbohydrate is made up of _

Answer 1

C, O and H, with H and O in a 2:1 ratio

Question 2

What are the two simplest monosaccharides?

Answer 2

Glyceraldehyde and dihydroxyacetone

Question 3

A monosaccharide is a carbohydrate with _

Answer 3

At least 3C, one in a double bond with oxygen, the others with hydroxyl groups

Question 4

In aldose sugars, the oxygen group is attached to _

Answer 4

A terminal end of the carbon chain

Question 5

In ketose sugars, the oxygen group is attached to _

Answer 5

A central carbon

Question 6

What is the name of the C=O bond group that characterises aldose sugars?

Answer 6

formyl/aldehyde

Question 7

What is the name of the C=O bond group that characterises ketose sugars?

Answer 7

ketone

Question 8

Chemical properties of enantiomers are _

Answer 8

Similar/the same

Question 9

Optical properties of enantiomers are_

Answer 9

Different

Question 10

Dihydroxyacetone is a _ sugar

Glyceraldehyde is a _ Sugar

Answer 10

Ketotriose/Ketose

Aldotriose/Aldose

Question 11

What is exceptional about dihydroxyacetone?

Answer 11

It has no chiral carbon atoms

Question 12

All saccharides with 4 or more carbon atoms _

Answer 12

Have at least one chiral carbon

Question 13

Aldotetrose sugars are diastereomers. What does this mean?

Answer 13

They have multiple chiral carbon atoms, and multiple pairs of enantiomers

Question 14

Number of pairs of enantiomers differs between ketose and aldose sugars in what way?

Answer 14

Ketose sugars have one less chiral carbon than aldose at the same total number of carbons.

Question 15

In a Fischer projection, vertical bonds represent

Answer 15

Bonds existing below the plane

Question 16

In a Fischer projection, horizontal bonds represent

Answer 16

Bonds existing above the plane

Question 17

What is the name given to cyclic forms of monosaccharides?

Answer 17

Furanose

Question 18

What name is given to the cyclic form of aldohexose sugars

Answer 18

Pyranose

Question 19

The alpha and beta forms of glucopyranose have different _

Answer 19

positioning of hydroxyl group on first carbon

Question 20

Alpha and beta forms of furanoses are _

Answer 20

Anomers

Question 21

A typical solution of d-glucose will contain which forms?

Answer 21

Both alpha and beta forms of glucopyranose in mixture. Some of the linear form in small amount

Question 22

What name is given to the conversion between anomeric alpha and beta forms?

Answer 22

Mutarotation

Question 23

What are steromers?

Answer 23

Isomers with same sequence of atoms, but with differing arrangement around one or more asymmetric centers

Question 24

What are epimers?

Answer 24

Diastereomers that differ in structure only at one chiral centre

Question 25

What two monomeric units compose sucrose (table sugar)?

Answer 25

Glucose and fructose

Question 26

What two monomeric units compose lactose?

Answer 26

Glucose and galactose

Question 27

What monomeric units compose maltose?

Answer 27

Glucose and glucose

Question 28

What is the name given to the linkage between hydroxyl groups on units in disaccharides?

Answer 28

O-glycosidic

Question 29

Can a unit of a disaccharide convert between its alpha and beta form?

Answer 29

Sometimes, depending on particular arrangement

Question 30

Why are oligosaccharides significant?

Answer 30

They function as a side chain group for some proteins

Question 31

What is the name for the process of attaching glycans to protein side chain?

Answer 31

Glycosylation

Question 32

Where are glycans attached to proteins?

Answer 32

Golgi apparatus

Question 33

In what way might the units of glycans have been modified?

Answer 33

Some hydroxyl groups may have been replaced by other groups

Question 34

How do you get glucosamine?

Answer 34

Replace a hydroxyl group on glucose with an amino group

Question 35

Glycans linked on hydroxyl groups are said to be _

Answer 35

O-linked

Question 36

Glycans linked on amino groups are said to be _

Answer 36

N-linked

Question 37

Adding an acetyl group to glucosamine gives _

Answer 37

N-acetylglucosamine

Question 38

Which molecule is derived from the nine carbon ketose neuraminic acid

Answer 38

N-acetylneuraminic acid

Question 39

What is a homopolysaccharide?

Answer 39

A polysaccharide with only one kind of monomeric unit

Question 40

What is a heteropolysaccharide?

Answer 40

A polysaccharide with multiple kinds of monomeric units

Question 41

Which type of bonding links monosaccharide units in polysaccharides?

Answer 41

Glycosidic

Question 42

What units make up starch?

Answer 42

Exclusively d-glucose

Question 43

What are the two type of starch molecules?

Answer 43

Amylose, amylopectin

Question 44

Roughly what is the range of number of units composing starch molecules?

Answer 44

300-5000+

Question 45

Which specific bonds link glucose units in both amylose and amylopectin

Answer 45

alpha 1->4 glycosidic

Question 46

Which bonds are branch points of amylopectin?

Answer 46

1->6

Question 47

How frequently do branches occur in amylopectin?

Answer 47

Around every 24-30 units in each linear chain

Question 48

What is the structure that starches take?

Answer 48

Tightly packed in to spherical granules

Question 49

How does starch function as energy storage?

Answer 49

Glucose units can be cleaved off of ends and used in energy generating processes

Question 50

What is the non-reducing end of starch molecules?

Answer 50

The glucose units with a free hydroxyl group on carbon number 4

Question 51

What can a reducing agent do?

Answer 51

Donate electrons to other molecules

Question 52

for linear configurations, ketose sugars __ aldose sugars

Answer 52

exist in equilibrium with the equivalent

Question 53

Why are ketose sugars slightly reducing?

Answer 53

In solution there will be a small amount of equivalent aldose sugars

Question 54

Why is there not a greater amount of interconversion between aldose and ketose sugars in the body?

Answer 54

The process prefers a higher pH

Question 55

How does the structure of glycogen compare to the structure of amylopectin?

Answer 55

It is very similar, but it has more branching points

Question 56

Cellulose is a _ chain with _ linkages between _ units

Answer 56

linear beta 1->4 glucose

Question 57

Why is cellulose able to give rigidity to structure?

Answer 57

The chains of molecules line up and participate in hydrogen bonding, forming closely associated networks

Question 58

What polysaccharide is a main component of bacterial cell walls?

Answer 58

Peptidoglycan

Question 59

Give an example of a heteropolysaccharide with its function

Answer 59

Hyaluronic acid - major component of extracellular matrix - vitreous humor - jelly stuff in the eyeball

Question 60

How are polysaccharides joined together in peptidoglycan?

Answer 60

By peptide bonds

Question 61

The group of molecules glycosaminoglycans are disaccharides of

Answer 61

N-acetyl and carboxylated units

Question 62

Lysozome, an enzyme in tears, saliva and mucus provides protection against bacteria by _

Answer 62

Breaking the beta 1->4 links between units of cell walls

Question 63

How does penicillin prevent bacterial growth?

Answer 63

It inhibits synthesis of peptidoglycan cell walls