Carbohydrates Flashcards
Elemental composition of carbohydrates
Carbon
Hydrogen
Oxygen
General formula for carbohydrates
Cm(H20)n
Monosaccharides
Monomers for carbohydrates
Simplest monosaccharide formula
(CH2O)n
Triose sugar
Lactic acid
Pentose sugar
Ribose
Hexose sugar
Glucose
Fructose
Properties of monosaccharides
Soluble, sweet
Structure of alpha glucose
C3, OH on top
Structure of beta glucose
C1, OH and H flipped
Glycosidic bonding
H and OH bond to form a bond with just oxygen
Release water, condensation reaction
Formation of maltose
Glucose and glucose
Formation sucrose
Glucose and fructose
Formation of lactose
Glucose and galactose
Properties of starch
Storage molecule in plants Insoluble Easily broken down, built up Small granules Food reserve formed when excess glucose formed from photosynthesis Fuel for respiration and gernimation Indirect food source for animals
Structure of starch
Alpha glucose polymer
Mixture of amylose and amylopectin
Amylose
Unbranched molecule
300 glucose units
1, 4 bond
Helical chain
Amylopectin
Branched chain
1300-1500 glucose units/molecules
1, 4, 1, 6 bonds
Structure related to function in starch
Large, insoluble
Highly branched, quick to break down
Folds easily, compact
Glycogen properties
Found in animal muscle and liver Insoluble, compact, easily broken down Granules in animals and fungi Alpha glucose polymer 1, 4, 1, 6 glycosidic bonds Smaller chains, 10-20 glucose units
Glycogen structure related to function
Highly branched, short chain nature, quickly converted into glucose, needed immediately in respiration
Large insoluble molecule, no effect on osmosis
Size ensures that enough is stored
Cellulose properties
Beta glucose polymer
Long unbranched chain 10000 monomers
1, 4 glycosidic 180 rotation
Hydrogen bonds formed between parallel chains for structural stability
Structure related to function
Cross linking between chains, stability
Structural support to cell walls
Cotton in fabric, rayon, cellophane
Hard to digest
Test for reducing sugars explanations
Monosaccharides gain electrons from Benedict’s reagent. (Solution of copper II sulphate)
Red precipitate copper I oxide formed when heated
Test for reducing sugars
Form solution of sample
Add equal volume of Benedict’s solution
Heat in hot water bath
Shows you relative amounts of monosaccharide present, semi quantitative test nature
Test for non reducing sugars
Non reducing as they do not change colour of Benedict’s reagent
Break down into monosaccharide by hydrolysis
Add dilute hydrochloride acid to hydrolyse disachs into monosaccs
Add NaHCO3 to neutralise acid
Test pH for alkaline solution
Reducing sugar test
