1. Monosaccharides

Question 1

What are monosaccharide molecules made from?

Answer 1

Carbon, hydrogen and oxygen.

Question 2

What functional group are monosaccharides?

Answer 2

Polyhydroxy aldehydes or ketones.

Question 3

What does polyhydroxy mean?

Answer 3

Poly means many, and hydroxy is an −OH group (like those found in alcohols).

Question 4

Ketones and aldehydes are organic molecules that contain which group?

Answer 4

Carbonyl group (C=O).

Question 5

Like water, monosaccharines contain twice as many what?

Answer 5

Hydrogens as oxygens.

Question 6

Aldehyde monosaccharides are known as what?

Answer 6

Aldoses.

Question 7

Ketone monosaccharides are known as what?

Answer 7

Ketoses, with the prefix keto-.

Question 8

What is this?

Answer 8

This monosaccharide has six carbon atoms, and the carbonyl group is at the end of the carbon chain, making it an aldehyde. Therefore, this is an aldohexose.

Question 9

What is this?

Answer 9

The monosaccharide below has five carbon atoms, and the carbonyl group is on the second carbon. Therefore this monosaccharide is a ketone. This is a ketopentose.

Question 10

As well as their ketone or aldehyde functional group, monosaccharides also have what groups?

Answer 10

Hydroxy groups.

Question 11

Why are monosaccharides highly soluble in water?

Answer 11

The hydroxy groups of monosaccharides are polar and can form hydrogen bonds with water. Therefore, because of their many hydroxy groups, monosaccharides are highly soluble in water.

Question 12

Because of these chiral carbons, monosaccharides will have what?

Answer 12

Optical isomers.

Question 13

Cyclic monosaccharides are often drawn as what?

Answer 13

Hawthorn projections.

Question 14

What is the most abundant monosaccharide?

Answer 14

Glucose.

Question 15

What is produced by plants during photosynthesis?

Answer 15

Glucose.

Question 16

What reaction creates glucose?

Answer 16

Carbon dioxide + water.

Question 17

The isomer produced by photosynthesis is always what?

Answer 17

D-glucose.

Question 18

Does the isomer L-glucose occur naturally?

Answer 18

No.

Question 19

In what form does glucose exist?

Answer 19

Both linear and cyclic form.

Question 20

The linear form of glucose is an aldehyde, and can therefore be identified with what?

Answer 20

Tollen’s reagent

Question 21

What are the three glucose isomers that exist in equilibrium in an aqueous solution?

Answer 21

Question 22

Glucose joins to other monosaccharides to form which disaccharides?

Answer 22

Sucrose and lactose.

Question 23

Which 3 monosaccharides make up most of the carbohydrates we eat?

Answer 23

Fructose, galactose and glucose.

Question 24

What is the difference between glucose and fructose?

Answer 24

Fructose usually forms a five-sided ring, whereas glucose forms a six-sided ring—even though they both have six carbon atoms.

Question 25

In its linear form fructose is a ___, not an ___ like glucose.

Answer 25

Ketone, aldehyde.

Question 26

Where is fructose found?

Answer 26

Plants, fruit.

Question 27

In many food sources, fructose exists as part of a disaccharide with glucose.

This forms what?

Answer 27

Sucrose.

Question 28

Is sucrose sweeter than fructose?

Answer 28

It is sweeter than pure glucose. However, pure fructose is nearly twice as sweet as sucrose.

Question 29

What is the difference between glucose and galactose?

Answer 29

Question 30

When do we usually consume galactose?

Answer 30

It is usually consumed as part of the disaccharide lactose which is the main sugar in milk.

Question 31

Carbohydrates are not the only molecules that taste sweet. What is another?

Answer 31

Aspartame, which is a methyl ester of a dipeptide and used to sweeten foods.

Question 32

What is a sugar?

Answer 32

A sweet carbohydrate.