Carbohydrates Flashcards
What are carbohydrates made of, and give 2 examples
Monomer called monosaccharides, like glucose, fructose or galactose
How are disaccharides formed
A condensation reaction between two monosaccharides eliminating a water molecule and forming a glycosidic bond
3 examples of disaccharides
Maltose
Lactose
Sucrose
What monosaccharides is maltose made of
Glucose and glucose
What monosaccharides is lactose made of
Alpha glucose and galactose
What monosaccharides is sucrose made of
Glucose and fructose
What are the 2 isomers of glucose
Alpha glucose
Beta glucose
What is the orientation of the oh group on alpha glucose
Down down up down
What is the orientation of the oh group on beta glucose
Up down up down
Structure of starch
1-4 and 1-6 glycosidic bonds
Made up of alpha glucose monomers
Function of starch
Amylose coils in an alpha helix shape to store more glucose in a compact space
Amylopectin in branched which increases its surface area so glucose is easily/ faster hydrolysed for respiration
Insoluble so doesn’t affect cells water potential
Large molecule that cannot leave cell
Structure of glycogen
1-4 and 1-6 glycosidic bonds
Monomers of alpha glucose
Function of glycogen
Stores glucose in liver, muscle and animal cells
Branched so larger surface area so glucose can easily/ faster hydrolysed for respiration
Insoluble so doesn’t affect cells water potential
Structure of cellulose
1-4 glycosidic bonds
Monomers of beta glucose
Function of cellulose
Many long and straight chains which link together by many hydrogen bonds to form fibrils which provide strength to the cell wall
Insoluble so doesn’t affect cells water potential
Test for reducing sugar
Heat with acid and neutralise (water bath)
Heat with Benedict’s solution
Red colour present
Examples of reducing sugars
All monosaccharides
Maltose and lactose
Test for non reducing sugars
First do Benedict’s to ensure no reducing sugar
Add Hcl as it will hydrolyse bonds within non reducing sugar
Boil sample
Neutralise using alkali like Naoh
Add Benedict’s reagent
Heat in water bath (80)
Positive =: blue->orange->yellow->brick red
Example of non reducing sugars
Sucrose
Test for starch
Extract liquid sample
Add 2 drops of iodine
Record colour change
Positive: orange to blue black
Negative: orange
