Carbohydrates

Question 1

What is a feature the cellulose wall has that makes it suitable for its function?

Answer 1

Provides rigity
Prevents cell from bursting as water enters by osmosis
Does this by exerting pressure inwards to stop further influx of water (providing maximum surface area for photosynthesis)

Question 2

How is the structure of cellulose is suited for its function?

Answer 2

Made up of beta glucose so forms long straight unbranched chains
Chains run parallel and are cross linked by hydrogen bonds (strengthen cell)
Microfibrils provide more strength

Question 3

What kind of monomers is Cellulose made out of?

Answer 3

Beta glucose

Question 4

What do the cellulose molecules grouped together form

Answer 4

Microfibrils
Microfibrils are then grouped together to form fibres

Question 5

Cellulose’s chains and branches

Answer 5

Has straight unbranched chains that run parallel to one another to form cross-linkages between adjacent chains

Question 6

Starch’s chains

Answer 6

Branched or unbranched
Unbranched wounds them into tight coil (making molecule compacy)

Question 7

Starch structure and function

Answer 7

Large, insoluble = water is not drawn into cells by osmosis
Compact = lots stored
Hydrolysed forms alpha glucose for respiration
Many ends on branches = enzymes act on it and glucose monomers are released rapidly

Question 8

Is starch insoluble in water

Answer 8

Yes

Question 9

Test for starch

Answer 9

1. Place 2cm3 sample being tested into test tube
2. Add 2 drops of iodine solution and shake/stir
3. If it turns black or blue it has starch

Question 10

Glycogens chains

Answer 10

Shorter chains
More highly branched

Question 11

Glycogen’s function/purpose

Answer 11

Carbohydrate storage

Question 12

Why is glycogen good for storage?

Answer 12

Insoluble = doesn’t draw water into cells and doesnt diffuse out of cells
Compact = lots can be stored in a small space
Highly branched = more ends acted on by enzymes. Can be broken easily for respiration

Question 13

Where is glycogen found in

Answer 13

Animals and bacteria
NEVER PLANTS

Question 14

What is the process called when water is added to disaccharides?

Answer 14

Hydrolysis

Question 15

What joins together to form Lactose?

Answer 15

Glucose and galactose

Question 16

Test for non-reducing sugars

Answer 16

(Benedicts test)
1. 2cm3 sample with 2cm3 of Benedicts reagent in test tube and filter
3. Boil for 5 mins
4. No colour change sugar not present
5. Add 2cm3 of sample to 2cm3 dilute hydrochloric acid and boil. Acid hydrolise disaccharide present in monosaccharides
6. Slowly add sodium hydrogencarbonate solution to neutralise acid
7. Test with pH paper => alkaline
8. Re-test resulting solution by heating it with 2cm3 of benedicts regent in boiling water for 5 mins
9. Orange-brown

Question 17

Whats the reaction called that forms the glycosidic bonds?

Answer 17

Condensation

Question 18

What joins together to form Sucrose?

Answer 18

Glucose and fructose

Question 19

What happens when polysaccharides are hydrolysed

Answer 19

BReak down into disaccharides or monosacchrides

Question 20

How are polysaccharides formed

Answer 20

Combining together many monosaccharide molecules

Question 21

Name the 3 disaccharides

Answer 21

Maltose
Sucrose
Lactose

Question 22

What joins together to form maltose?

Answer 22

Glucose and glucose

Question 23

Difference between condensation and hydrolysis

Answer 23

Condensation = giving out water in reactions
Hydrolysis = taking in of water to split molecules

Question 24

What is the reaction called when monosaccharides join together?

Answer 24

Condensation

Question 25

Name the 3 polysaccharides

Answer 25

Starch
Glycogen
Cellulose

Question 26

Describe polysaccharides molecules

Answer 26

Very large
Insoluble
Making then suitable for storage

Question 27

What happens to disaccharide when water is added to it (under suitable conditions)?

Answer 27

Breaks down the glycosidic bond releasing constituent

Question 28

What chains is starch made up of and what bonds form?

Answer 28

Alpha glucose monosaccharides linked by glycosidic bonds

Question 29

What is the bond formed when monosaccharides join together?

Answer 29

Glycosidic

Question 30

What is a monomer?

Answer 30

Small repeating unit from which larger molecules are made from

Question 31

Lactulose is a dissacharide formed from one molecule of galactose and one molecule of fructose
Other than both being disaccharides give one similarity and one difference between the structure of lactulose and lactose

Answer 31

Similarity: Both contain galactose/glycosidic bond
Difference: Lactulose contains fructose, whereas lactose contains glucose