Carbohydrates Flashcards
What is a feature the cellulose wall has that makes it suitable for its function?
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)
How is the structure of cellulose is suited for its function?
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
What kind of monomers is Cellulose made out of?
Beta glucose
What do the cellulose molecules grouped together form
Microfibrils
Microfibrils are then grouped together to form fibres
Cellulose’s chains and branches
Has straight unbranched chains that run parallel to one another to form cross-linkages between adjacent chains
Starch’s chains
Branched or unbranched
Unbranched wounds them into tight coil (making molecule compacy)
Starch structure and function
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
Is starch insoluble in water
Yes
Test for starch
- Place 2cm3 sample being tested into test tube
- Add 2 drops of iodine solution and shake/stir
- If it turns black or blue it has starch
Glycogens chains
Shorter chains
More highly branched
Glycogen’s function/purpose
Carbohydrate storage
Why is glycogen good for storage?
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
Where is glycogen found in
Animals and bacteria
NEVER PLANTS
What is the process called when water is added to disaccharides?
Hydrolysis
What joins together to form Lactose?
Glucose and galactose
Test for non-reducing sugars
(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
Whats the reaction called that forms the glycosidic bonds?
Condensation
What joins together to form Sucrose?
Glucose and fructose
What happens when polysaccharides are hydrolysed
BReak down into disaccharides or monosacchrides
How are polysaccharides formed
Combining together many monosaccharide molecules
Name the 3 disaccharides
Maltose
Sucrose
Lactose
What joins together to form maltose?
Glucose and glucose
Difference between condensation and hydrolysis
Condensation = giving out water in reactions
Hydrolysis = taking in of water to split molecules
What is the reaction called when monosaccharides join together?
Condensation
Name the 3 polysaccharides
Starch
Glycogen
Cellulose
Describe polysaccharides molecules
Very large
Insoluble
Making then suitable for storage
What happens to disaccharide when water is added to it (under suitable conditions)?
Breaks down the glycosidic bond releasing constituent
What chains is starch made up of and what bonds form?
Alpha glucose monosaccharides linked by glycosidic bonds
What is the bond formed when monosaccharides join together?
Glycosidic
What is a monomer?
Small repeating unit from which larger molecules are made from
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
Similarity: Both contain galactose/glycosidic bond
Difference: Lactulose contains fructose, whereas lactose contains glucose
Name the three monosaccharides
Glucose fructose galactose
Name another monomer thats very common
Glucose ATP
Name different types og glucose monomers
Trioses (3C)
Pentose (5C) - ribose
Hexose (6C) - glucose
