Biochemistry Flashcards
Carbohydrates are made of?
Carbon, hydrogen and oxygen
Main groups of carbohydrates?
Monosaccharides
Disaccharides
Polysaccharides
General formula of a monosaccharide?
(CH2O)n
Monosaccharide structure?
(CH2O)n formula
Contain carbonyl group (C=O)
Classified by number of carbons in carbon skeleton (triose, pentose)
Structure of glucose?
C6H12O6
Hexose sugar
Straight line or ring structure
In aqueous solution a cylindrical ring is formed, more stable
Difference between Alfa glucose and beta glucose?
Alfa has hydroxyl group on bottom
Beta has hydroxyl group on top
Examples of monosaccharide?
Glucose Fructose Galactose Ribose Deoxyribose
Maltose is made up of?
Two Alfa glucose molecules
Sucrose is made up of?
One alfa glucose and one beta fructose
Lactose is made up of?
One beta galactose and one Alfa glucose
How do monosaccharides form disaccharides?
Condensation reaction forming a glycosidic bond between a hydroxyl group from each molecule
Main polysaccharides?
Starch
Cellulose in plants
Glycogen in animals
Structure of starch?
Made of many Alfa glucose molecules
Either amylose and amylopectin
Amylose forms helix structure only 1,4 bonds
Amylopectin forms branch structure has 1,4 and 1,6 bonds
How to test for starch?
Use iodine
Positive is blue/black blue to iodine molecules fitting down helix structure of amylose forming a polyiodide-starch complex
Structure of glycogen?
Similar to amylopectin but more branches
1,6 bonds to form branches
Compact structure
Stored in muscles and liver cells
Structure of cellulose?
Made up of beta glucose molecules
1,4 bonds
Molecules have to rotate 180 to bond leading to long chain, hydrogen bonds form between parallel chains giving it strength
How to test for reducing sugars?
Benedicts test Reducing sugars donate an electron to copper and become oxidised to a carboxylic acid Blue= zero Green= low Orange= medium Red= high
Reducing vs non- reducing sugar?
Reducing contain an aldehyde or ketone group whereas non reducing do not
How to test for non-reducing sugars?
Heat with HCL to hydrolyse then as sodium bicarbonate to neutralise before performing benedicts test
Structure of lipids?
Contain carbon, hydrogen and oxygen
Insoluble in water, hydrophobic, non-polar, covalent bonds
Triglycerides, cholesterol, steroid, wax and phospholipids
Not true polymers
Structure of triglyceride?
Glycerol backbone joined to three fatty acid chains joined together by ester bond formed in a condensation reaction between OH group of glycerol and COOH of fatty acid
Structure of glycerol?
An alcohol
Formula of C3H8O3
Contains three hydroxyl groups