Monosaccharides and their Properties

Question 1

Define monosaccharides

Answer 1

the simplest form of carbs that can’t be further hydrolyzed into sugars

Question 2

Monosaccharides are colorless, ______ solids that are _______ in water, but insoluble in _______ solvents. Most have a _____ taste.

Answer 2

crystalline
very soluble
nonpolar
sweet

Question 3

What is the backbone of common monosaccharides?

Answer 3

unbranched carbon chains

-all the carbons are linked by single bonds

Question 3

What is the backbone of common monosaccharides?

Answer 3

unbranched carbon chains in which all the carbons are linked by single bonds

Question 4

The carbon atoms are given numbers starting from _________. In glucose, the first carbon is the __________ group.

Answer 4

the first carbon

aldehydic group

Question 5

Nomenclature ; According to the presence of an aldehyde or ketone group:
-Ose means:

Answer 5

aldose (containing an aldehyde group)
ketose (containing a ketone group)
-ose means sugar

Question 6

Nomenclature: According tot he number of carbon atoms:

Answer 6

trioses (monosacchrides containing 3 carbons)
tetroses (4)
pentoses (5)
hexoses (6)
heptoses (7)

Question 7

Nomenclature: According to the presence of an aldehyde or ketone groups and number of carbon atoms

Answer 7

• aldotriose and keto triose
• aldotetrose and ketotetrose
• aldopentoses and ketopentose

Question 8

Trioses

Answer 8

• aldotriose (glyceraldhyde)
• ketotrioses (dihydroxyaceton)
• review the structure

Question 9

Tetroses

Answer 9

Monosaccharides containing 4 carbon atoms:
aldotetrose (erythrose)
ketotetrose (erythrulose)

Question 10

Pentoses

Answer 10

5 carbon atoms
aldopentoses (ribose, arabinose, xylose, and lyxose)
ketopentoses (cellulose)

Question 11

Function of pentoses

Answer 11

ATP GTP NAD NADP glycoproteins in animals and plants

Question 12

Hexoses

Answer 12

Aldohexoses: glucose, mannose
ketohexose: fructose

Question 13

What are the simplest monosaccharides?

Answer 13

the 2 three-carbon trioses:
D-glyceraldehyde (aldotriose)
dihydroxyacetone (ketotriose)

Question 14

What are the most common monosaccharides in nature?

Answer 14

the aldohexose D-glucose

the ketohexose D-fructose

Question 15

What are the components of nucleotides and nucleic acids?

Answer 15

the aldopentoses: D-ribose and 2-deoxy-D-ribose

Question 16

Glucose is:

Answer 16

• the most important sugar of CHO
• the main sugar in blood
• one of the major sources of energy

Question 17

Glucose Properties

Answer 17

• the straight-chain structural formula can account for some of the properties of glucose
• however, a cyclic structure is thermodynamically favored and accounts for other properties

Question 18

What is a cyclic structure formed by?

Answer 18

the reaction between the aldehyde group and a hydroxyl group

Question 19

Many of the carbon atoms to which hydroxyl groups are attached are __________. This gives rise to the man _________ found in monosaccharides.

Answer 19

chiral centers

stereoisomers

Question 20

Stereoisomers

Answer 20

isomers that differ in spatial arrangement of atoms

Question 21

Isomerism

Sugars exhibit various forms of _____.

Answer 21

isomerism

Question 22

Isomers

Answer 22

molecules that have the same chemical formula but different chemical structures

Question 23

Asymmetric Carbon

Answer 23

an important determinant of isomerism

Question 24

Asymmetric carbon (2)

Answer 24

a carbon atom to which 4 different atoms or groups of atom are attached is said to be asymmetric

Question 25

Presence of asymmetric carbon also ________.

Answer 25

exhibits optical activity on the compound

Question 26

What happens when a beam of plane-polarised light is passed through a solution?

Answer 26

it will be rotated to the right or left in accordance with the type of compound

Question 27

The Optical Isomers: When it is rotated to the right, the compound is called ______. When it is rotated to the left, the compound is called ________.

Answer 27

Dextrorotatory (D or + sign) | Laevorotatory (L or - sign)

Question 28

What does the D-series and L-series refer to?

Answer 28

the orientation of the H and OH groups around the carbon atom just adjacent to the terminal primary alcohol carbon

Question 29

Which atom in glucose determines the series?

Answer 29

C-atom 5

Question 30

When the OH group on this carbon is on the right, it belongs to _______, when the - OH group is on the left, it is a member of _________.

Answer 30

D-series | L-series

Question 31

2 isomers of glucose- D-glucose and L-glucose are

Answer 31

mirror images of each other

Question 32

D- and L- isomers are

Answer 32

mirror images of each other (enantiomers)

Question 33

Examples of D-Aldoses with 3 carbons are

Answer 33

Glyceraldehyde

Question 34

Examples of D-Aldoses with 4 carbons are

Answer 34

D-erythrose | D-Threose

Question 35

Examples of D-Aldoses with 5 carbons are:

Answer 35

D-ribose D-arabinose D-xylose D-lyxose

Question 36

Examples of D-Aldoses with 6 carbons are

Answer 36

``` D-allose D-altrose D-glucose D-mannose D-gulose D-idose D-galactose D-talose ```

Question 37

Examples of D-Ketoses with 3 carbons

Answer 37

Dihydroxyacetone

Question 38

Examples of D-Ketoses with 4 carbons

Answer 38

D-erythrulose

Question 39

Examples of D-Ketoses with 5 carbons

Answer 39

D-ribulose | D-xylulose

Question 40

Examples of D-Ketoses with 6 carbons

Answer 40

D-Psicose D-Fructose D-sorbose D-tagatose

Question 41

Epimerism

Answer 41

2 sugars which differ from 1 another only in configuraion around a single carbon atom are called epimers

Question 42

Glucose and galactose are examples of

Answer 42

epimeric pairs which differ only with respect of C4

Question 43

Mannose and glucose are epimers in respect of

Answer 43

C2

Question 44

Epimerisation

Answer 44

process by which one epimer is converted to the other | it requires the enzyme epimerase

Question 45

What is an example of epimerisation?

Answer 45

conversion of galactose to glucose in the liver

Question 46

What is an example of epimerisation?

Answer 46

conversion of galactose to glucose in the liver

Question 47

The cyclic forms of carbohydrates can exist in 2 forms

Answer 47

a- and b-

Question 48

What are these 2 forms based on?

Answer 48

based on the position of the substituent at the anomeric center

Question 49

The 2 forms are sometimes described as _____ since they are _______ at the anomeric center

Answer 49

anomers, isomers

Question 50

When does a cyclic structure 'take place'?

Answer 50

as the 2 reacting groups aldehyde and alcoholic group belong to the same molecule

Question 51

Mutarotation

Answer 51

during dissolving of a saccharide in water the equilibrium between anomers is established

Question 52

The rings structures of monosaccharides are similar to the ring structures of either

Answer 52

pryan or furan

Question 53

Define pyran and furan

Answer 53

a 6-membered ring | a 5-membered ring

Question 54

For glucose in solution, more than

Answer 54

99% is in the pyranose form

Question 55

The aldehyde and ketone moieties (parts) of the monosaccharides with 5 and 6 carbons will spontaneously react with

Answer 55

a hydroxyl group present in neighboring carbons to produce intramolecular hemiacetals or hemiketals (respectively)

Question 56

Hemiacetal or hemiketal formation results in the formation of

Answer 56

5 or 6 membered rings

Question 57

The 5 membered ring structure resembles the ____, thus sugars with this structure are called __________.

Answer 57

furan | furanoses

Question 58

Those with 6 membered rings resemble the _______ and are termed _______.

Answer 58

pyran | pyranoses

Question 59

Pyranoses =

Answer 59

aldohexoses

Question 60

Furanoses =

Answer 60

fructose ribose

Question 61

Due to the presence of a free aldehyde or ketone group, carbohydrates are readily _______ and behave as _______ ________.

Answer 61

oxidized , reducing agents

Question 62

These sugars have the capacity to reduce _____ to ______. Therefore, only the reducing sugars like ____ will give ______ _______.

Answer 62

Cupric ion (Cu 2+) , cuprous ion (Cu+) , glucose, positive reactions