Carbohydrates

Question 1

What elements do carbohydrates contain

Answer 1

O C and H

Question 2

What is the ration of hydrogen to oxygen in carbohydrate

Answer 2

2:1 same as water

Question 3

What is a monosaccharide

Answer 3

Monomer from which larger carbohydrates can be made

Question 4

What are the components of a monosaccharide

Answer 4

sweet tasting, insoluble, and single sugar molecules

Question 5

What are the 3 types of monosaccharides

Answer 5

Glucose
Galactose
Fructose

Question 6

Describe the formation of the right sided H and OH in an Alpha glucose molecule

Answer 6

H on top of OH

Question 7

Describe the formation of the right sided H and OH in a beta glucose molecule

Answer 7

OH on top of H

Question 8

What is a Disaccharide

Answer 8

A double sugar molecule produced by 2 monosaccharides in a condensation reaction

Question 9

Describe a Condensation reaction

Answer 9

Formation of a chemical bond between two molecules which eliminates a water molecule

Question 10

Describe a hydrolysis reaction

Answer 10

Breaking of a chemical bond between two molecules which adds a water molecule

Question 11

What reaction adds a water molecule to two molecules

Answer 11

Hydrolysis reaction

Question 12

What reaction eliminates a water molecule from two molecules

Answer 12

Condensation reaction

Question 13

In glucose molecules is it OH H or H OH connected to the top of the 1,2 and 1,3 carbons

Answer 13

OH H is

Question 14

What molecule do two alpha glucose molecules join to make

Answer 14

Maltose

Question 15

What molecule does an alpha glucose molecule and a fructose molecule join to make

Answer 15

Sucrose

Question 16

What molecule does an alpha glucose and a galactose molecule join to make

Answer 16

Lactose

Question 17

What is a polysaccharide

Answer 17

Many monosaccharides joined by glycosidic bonds formed by condensation reaction

Question 18

Where is starch found

Answer 18

In many parts of plants in the form of small granules or large grains

Question 19

Where is glycogen found

Answer 19

In the cytoplasm of animal cells as tiny granules. in the liver and some muscles

Question 20

Where is cellulose found

Answer 20

In the cell walls of plants

Question 21

What is the function of starch

Answer 21

As an energy storage

Question 22

What is the function of glycgogen

Answer 22

As an energy storage

Question 23

What is the function of cellulose

Answer 23

As a structural support for plant cells

Question 24

What structural features of starch helps it with its function (4)

Answer 24

Helical shape - allows it to be more compact and take up smaller volumes

Insoluble-Doesn’t dissolve in water so it has no osmotic effect and can’t dissolve from cells

Large molecule- can’t dissolve from cells

Branched- can be hydrolysed rapidly as the enzymes on free ends so its broken down faster

Question 25

What structural features of glycogen help with its function (3)

Answer 25

Compact- so it takes up less volume Insoluble-Doesn't dissolve in water so it has no osmotic effect and can't dissolve from cells very highly Branched- can be hydrolysed rapidly as the enzymes on free ends so its broken down faster than starch as there are more branches

Question 26

What structural features of cellulose help with its function

Answer 26

Many parallel Beta glucose chains linked by hydrogen bonds forming microfibrils This makes cellulose very strong and stable

Question 27

What are the three polysaccharides

Answer 27

Cellulose Starch Glycogen

Question 28

What polysaccharides are made up of Alpha glucose

Answer 28

Glycogen and Starch

Question 29

What polysaccharides are made up of Beta glucose

Answer 29

Cellulose

Question 30

What is the test for a reducing sugar

Answer 30

Put 2cm cubed of food sample in a test tube. if not in liquid form already grind it up to be Add an equal volume of benedict reageant Heat the mixture in a boiling water bath for 5 minutes

Question 31

What results should you get for a benedict test

Answer 31

Blue-> green-> yellow-> orange-> red

Question 32

What two molecules make up starch

Answer 32

Amylose and Amylopectin

Question 33

Describe amylose

Answer 33

Polymer of alpha glucose linked by glycosidic bonds between the C1 and C4, Consists of long straight chains which coil to give amylose a spiral shape

Question 34

Describe amylopectin

Answer 34

Polymer of alpha glucose linked by glycosidic bonds between the C1 and C6 which result in a compact branched structure

Question 35

Where are the Glycosidic bonds between glucose formed

Answer 35

C1 and C4 In beta glucose this means they need to be inverted each time rather than straight chains

Question 36

Describe the iodine test

Answer 36

Grind up a food sample and dissolve it in distilled water Add a few drops of iodine to the solution over a period of time the colour should become bluey black if starch is present

Question 37

What colour is shown from an iodine test if starch is present

Answer 37

Bluey black