B M 1 : Carbohydrates

Question 1

What are most carbohydrates?

Answer 1

Polymers

Question 2

What are polymers? And what are they composed of?

Answer 2

Large, complex molecules composed of long chains of monomers joined together

Question 3

What are monomers?

Answer 3

Small, basic molecular units

Question 4

What are examples of monomers?

Answer 4

• monosaccharides
• amino acid
• nucleotides

Question 5

What are most carbohydrates made of?

Answer 5

Monosaccharides

Question 6

What elements do app carbohydrates contain?

Answer 6

Carbon
Hydrogen
Oxygen

Question 7

What is glucose?

Answer 7

A hexose sugar - a monosaccharide with six carbon atoms in each molecule

Question 8

What are the two types of glucose?

Answer 8

Alpha and beta glucose

Question 9

What are alpha and beta known as?

Answer 9

Isomers ( molecules with the same molecular structure formula as each other, but with atoms connected in a different way)

Question 10

What group is reversed in alpha-glucose?

Answer 10

Right hand side group
Hydrogen on top
Oxygen and hydrogen on bottom

Question 11

What group is reversed in beta-glucose?

Answer 11

Right hand side group
Hydrogen on bottom
Hydrogen and oxygen on top

Question 12

What reaction joins monosaccharides together?

Answer 12

Condensation reaction

Question 13

What’s a condensation reaction?

Answer 13

When two molecules join together with the formation of a new chemical bond, and water molecules is released when bond is formed

Question 14

What bond is formed between two monosaccharides as a molecule of water is released?

Answer 14

Glycosidic bond

Question 15

What if formed when two monosaccharides join together?

Answer 15

A disaccharide

Question 16

What disaccharide is formed from a condensation reaction between glucose and a fructose molecule?

Answer 16

Sucrose

Question 17

What disaccharide is formed from a glucose molecule and a galactose molecule?

Answer 17

Lactose

Question 18

What reactions breaks polymers and apart?

Answer 18

Hydrolysis reactions

Question 19

What are polymers broken down into?

Answer 19

Monomers

Question 20

What does a hydrolysis reaction do?

Answer 20

Breaks chemical bonds between monomers using a water molecules

Question 21

What test do you use to test for sugars?

Answer 21

Benedict’s test

Question 22

What is sugar a general term for?

Answer 22

Monosaccharides and disaccharides

Question 23

What are all sugars classed as?

Answer 23

Reducing or non-reducing

Question 24

What does reducing sugars include?

Answer 24

All monosaccharides (eg glucose)
And some disaccharides (eg maltose and lactose)

Question 25

How to test with Benedict’s reagent (which is blue)

Answer 25

Add it to a sample and heat it in a water bath that’s been brought to a boil

Question 26

What happens if the test is positive?

Answer 26

It will form a coloured precipitate (solid particles suspended in the solution)

Question 27

The colour precipitate changes from?

Answer 27

Blue > green> yellow >orange > brick red

Question 28

Th higher the concentration of reducing sugar?

Answer 28

The further the colour changes | -can use to compare the amount of reducing sugar in different solutions

Question 29

What’s a more accurate way to compare the amount of reducing sugars in a solution?

Answer 29

Filter the solution and weight the precipitate

Question 30

Could there’s still be non-reducing sugars present if the Benedict’s test for reducing sugars is negative?

Answer 30

Yes

Question 31

How to test for non-reducing sugars?

Answer 31

1) break down into monosaccharides (get new sample of test solution, adding dilute hydrochloride acid and heat in water bath until brought to a boil 2) neutralise it with sodium hydrogen-carbonate 3) carry out Benedict’s test like you would die reducing sugars

Question 32

If test is positive for non reducing sugars what happens?

Answer 32

Forms coloured precipitate (as for reducing sugars test)

Question 33

If test negative for non-reducing sugars what happens?

Answer 33

The solutions stays blue, meaning it doesn’t contain any sugar (either reducing or non-reducing

Question 34

What are polysaccharides?

Answer 34

Loads of sugars joined together

Question 35

How is a polysaccharide formed?

Answer 35

When more than two monosaccharides are joined together by condensation reactions

Question 36

Starch is what in plants?

Answer 36

The main energy storage material -plants store excess glucose as starch

Question 37

What is starch a mixture of?

Answer 37

Two polysaccharides of alpha-glucose -amylose and amylopectin

Question 38

Amylose is what?

Answer 38

A long, unbranched chain of a-glucose

Question 39

What’s the structure of amylose like?

Answer 39

Angles of glycosidic bonds give it a coiled structure | Makes it compact so really good for at storage because you can fit more in a small space

Question 40

Amylopectin is what?

Answer 40

A long, branched chain of a-glucose

Question 41

Amylopectin structure?

Answer 41

Side branches allow the enzymes that break down the molecule to get at the glycosidic bonds easily Means glucose can be released quickly

Question 42

About starch

Answer 42

* It’s insoluble in water * It doesn’t affect water potential so doesn’t cause water to enter cells by osmosis which would make them swell * makes it good for storage

Question 43

What test do you used to test for starch?

Answer 43

The iodine test

Question 44

How to test for starch?

Answer 44

Add iodine dissolved in a potassium iodide solution to the test sample

Question 45

Is starch is present what happens?

Answer 45

The sample changes from browny-orange to a dark blue-black colour

Question 46

What’s the main energy storage material in animals?

Answer 46

Glycogen

Question 47

whats excess glucose stored as?

Answer 47

Glycogen

Question 48

what is glycogen?

Answer 48

polysaccharide of alpha glucose

Question 49

whats the structure of alpha glucose like?

Answer 49

Similar to amylopectin except has loads more side branches coming off of it - loads of branches means stored glucose can be released more quickly - very compact = good for storage

Question 50

whats a major component of cell walls in plants?

Answer 50

cellulose

Question 51

whats cellulose made of?

Answer 51

Long, unbranched chains of beta-glucose - when beta-glucose molecules bond they form straight cellulose chains - these chains are linked together by hydrogen bonds to form strong fibers called microfibrils

Question 52

what does the strong fibers in cellulose structure mean cellulose is good for?

Answer 52

providing structural support