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Flashcards in B M 1 : Carbohydrates Deck (52):
1

What are most carbohydrates?

Polymers

2

What are polymers? And what are they composed of?

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

3

What are monomers?

Small, basic molecular units

4

What are examples of monomers?

- monosaccharides
- amino acid
- nucleotides

5

What are most carbohydrates made of?

Monosaccharides

6

What elements do app carbohydrates contain?

Carbon
Hydrogen
Oxygen

7

What is glucose?

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

8

What are the two types of glucose?

Alpha and beta glucose

9

What are alpha and beta known as?

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

10

What group is reversed in alpha-glucose?

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

11

What group is reversed in beta-glucose?

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

12

What reaction joins monosaccharides together?

Condensation reaction

13

What’s a condensation reaction?

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

14

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

Glycosidic bond

15

What if formed when two monosaccharides join together?

A disaccharide

16

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

Sucrose

17

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

Lactose

18

What reactions breaks polymers and apart?

Hydrolysis reactions

19

What are polymers broken down into?

Monomers

20

What does a hydrolysis reaction do?

Breaks chemical bonds between monomers using a water molecules

21

What test do you use to test for sugars?

Benedict’s test

22

What is sugar a general term for?

Monosaccharides and disaccharides

23

What are all sugars classed as?

Reducing or non-reducing

24

What does reducing sugars include?

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

25

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

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

26

What happens if the test is positive?

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

27

The colour precipitate changes from?

Blue > green> yellow >orange > brick red

28

Th higher the concentration of reducing sugar?

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

29

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

Filter the solution and weight the precipitate

30

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

Yes

31

How to test for non-reducing sugars?

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

32

If test is positive for non reducing sugars what happens?

Forms coloured precipitate (as for reducing sugars test)

33

If test negative for non-reducing sugars what happens?

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

34

What are polysaccharides?

Loads of sugars joined together

35

How is a polysaccharide formed?

When more than two monosaccharides are joined together by condensation reactions

36

Starch is what in plants?

The main energy storage material

-plants store excess glucose as starch

37

What is starch a mixture of?

Two polysaccharides of alpha-glucose -amylose and amylopectin

38

Amylose is what?

A long, unbranched chain of a-glucose

39

What’s the structure of amylose like?

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

40

Amylopectin is what?

A long, branched chain of a-glucose

41

Amylopectin structure?

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

42

About starch

*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

43

What test do you used to test for starch?

The iodine test

44

How to test for starch?

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

45

Is starch is present what happens?

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

46

What’s the main energy storage material in animals?

Glycogen

47

whats excess glucose stored as?

Glycogen

48

what is glycogen?

polysaccharide of alpha glucose

49

whats the structure of alpha glucose like?

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

50

whats a major component of cell walls in plants?

cellulose

51

whats cellulose made of?

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

52

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

providing structural support