3.3/3.4 Carbohydrates

Question 1

What do carbs contain

Answer 1

Carbon
Hydrogen
Oxygen

Question 2

What’s a monosaccharide

Answer 2

A single sugar unit
Glucose
Fructose
Ribose

Question 3

What’s a disaccharide

Answer 3

2 monosaccharides
Lactose
Sucrose
Maltose

Question 4

What’s a polysaccharide

Answer 4

Polymer of monosaccharides
Glycogen
Cellulose
Starch

Question 5

What is the formula for glucose

Answer 5

C6 H12 O6

Question 6

What is glucose

Answer 6

A hexose monosaccharide

Monosaccharide composed of 6 carbons

Question 7

What are the two variations of glucose

Answer 7

Beta and alpha

When alpha lay next to each other they’re hydroxyl groups can easily react

Question 8

What bonding will occurs in the condensation reaction between 2 alpha glucose

Answer 8

1,4 glycosidic bond between carbon 1 and carbon 4

Water is formed from the 2 H atoms and 1 O atom

Question 9

What are the main characteristic of glucose and why is this

Answer 9

They are polar and soluble due to the hydrogen bonds

Question 10

What are the 3 main feature of starch and glycogen

Answer 10

They are compact

Soluble and branched which makes them efficient storage

Question 11

How is starch and glycogen formed

Answer 11

Alpha glucose are joined by glycosidic bonds to form polysaccharides

Question 12

What are the 2 types of starch

Answer 12

Amylose

Amylopectin

Question 13

What is the structure of amylose

Answer 13

Made form 1,4 glycosidic bonds forming a helix shape that is compact and hydrogen bonds between the structure stabilises it

Question 14

What is the structure of amylopectin

Answer 14

Made from 1,4 and 1,6 glycosidic bonds giving it a branched structure

Question 15

What’s the differences between glycogen and starch

Answer 15

Glycogen is the energy store molecule in animals and it forms more branches than starch so is more compact and needs less space to be stored

Question 16

How do starch and glycogen release the glucose they need for respiration

Answer 16

Through hydrolysis

Addition of water

Question 17

What are cellulose made of

Answer 17

Beta glucose

Question 18

How do beta glucose form

Answer 18

One glucose needs to be turned upside down

Question 19

What is the structure when beta glucose join

Answer 19

A straight chain is created which is called cellulose

It is unable to coil or form branches

Question 20

What are forms when the chain forms hydrogen bonds

Answer 20

Microfibrils form

These microfibrils join to make macrofibrils and these then combine to make fibres

Question 21

What are the characteristics of the fibres In cellulose

Answer 21

They are strong and insoluble

So they make cell walls which are hard to break

Question 22

What is the test used on reducing sugars

What are reducing sugars

Answer 22

Benedicts test
Place sample in boiling tube, add equal volume of benedicts reagent, heat mixture gently in boiling water bath for 5mins
Reducing sugars are monosaccharides and they donate electrons

Question 23

What is the colour sequence of the benedict test

Answer 23

Blue 
Green 
Yellow
 orange 
Brick red

Question 24

What is the test for non reducing sugars

Answer 24

First boil solution with dilute hydrochloric acid then use the benedicts test
You have to hydrolyse the sucrose

Question 25

What is the test for starch

Answer 25

Iodine test
Yellow brown to purple black
Add a few tops of iodine dissolved in potassium iodid solution mixed with a sample

Question 26

What price of equipment measures the colour of a liquid

Answer 26

Colorimeter

Question 27

What do reagent strips do

Answer 27

Test presence of sugars and the concentration of sugar can be determined