3.1.2-Carbohydrates Flashcards
(19 cards)
What are monosaccharides?
The monomers from which larger carbohydrates are made
what is formed when 2 monosaccharides join?
Disaccharide
Name the bond formed between two monosaccharides
Glycosidic
Glucose+Glucose—>
Maltose
Glucose+Fructose—>
sucrose
Glucose+galactose—>
Lactose
How do you test for reducing sugars and what is the positive result?
Add benedict’s reagent+heat
Blue->green/yellow/brick red
Starch
Monomers-alpha glucose
Bond between monomers-1-4 and 1-6 glycosidic bonds
Function-Store of glucose
Location-Plant cells
How structure relates to function-Coiled so compact
-branched so glucose easily released for respiration
-Insoluble won’t affect water potential
-large molecule so cant leave cell
Cellulose
Monomers-beta glucose
Bond between monomers-1-4 glycosidic bonds
Function-Structure strength for cell wall
Location-Plant cell wall
-Long straight chains of beta glucose
-Joined by hydrogen bonds
-to form fibrils
-provide strength
Glycogen
Monomers-Alpha glucose
Bond between monomers-1-4 and 1-6 glycosidic bonds
Function-Store of glucose
Location-Animals mainly muscle cells
Structure-Highly branched
How structure relates to function-Branches increase surface area for rapid hydrolysis back to glucose
-Insoluble so
won’t affect water potential
-Compact molecule good for storage
How to test for starch?
What is a positive result?
Iodine
Orange—>black
How do you test for non-reducing sugars?
Do Benedict’s test and stays blue
Boil with hydrochloric acid then neutralise with alkali
Heat with Benedict’s and becomes brick red
Describe 2 differences between the structure of a cellulose molecule and a glycogen molecule
1.Cellulose has beta glucose monomers and glycogen has alpha glucose monomers
2.Cellulose has straight chain and glycogen is coiled
Describe and explain 2 features of starch that make it a good storage molecule
1.Insoluble so doesn’t affect water potential
2.Coiled so makes molecule compact
Describe how the structure of glycogen is related to its function (4)
1.Coiled so compact
2.Insoluble so doesn’t affect water potential
3.Branched so more ends for faster hydrolysis
4.Polymer of glucose so easily hydrolysed
Explain one way starch molecules are adapted for their function in plant cells
Insoluble so don’t affect water potential
Explain how cellulose molecules are adapted to their function in plant cells (3)
1.Long and straight chains
2.Become linked together by many hydrogen bonds to form fibrils
3.Provide strength
What is the main biological molecule in the cell wall?
murein
Suggest how glycogen acts as a source of energy
Hydrolysed to glucose
Glucose used in respiration
