Bodies main energy source CH 2 O Only plants synthesise carbohydrates Starch, Cellulose...
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Transcript of Bodies main energy source CH 2 O Only plants synthesise carbohydrates Starch, Cellulose...
Bodies main energy source
CH2O
Only plants synthesise carbohydrates
Starch, Cellulose (polysaccharides)
Lactose, sucrose (dissaccharides)
Glucose, fructose (monosaccharides)
CARBOHYDRATES
(CH2O)n where n=3 to 9
Aldehydes or ketones containing a carbonyl group and at least 2 hydroxyl groups
Hexoses (glucose, galactose, fructose)
MONOSACCHARIDES
Contain 5 carbon atoms
Ribose
PENTOSES
Low molar masses
Sweet
Soluble in water
Crystalline solids
Reducing sugars (aldehyde group oxidised)
PROPERTIES OF MONO AND DI-SACCHARIDES
STRUCTURE OF GLUCOSE
INTERCONVERSION OF Α AND Β GLUCOSE
STRAIGHT CHAIN AND CYCLIC FRUCTOSE
CONDENSATION OF MONOSACCHARIDES
DISACCHARIDE FORMATION
Β-glucose + β-galactose -----> lactose
α-glucose + α-glucose -------> maltose
α-glucose + β-fructose ------> sucrose
Numerous monosaccharide units
Large masses
Not sweet, non-reducing, insoluble
Starch is plant store for glucose
Two forms :
Amylose (water soluble)
Amylopectin (water insoluble)
POLYSACCHARIDES
α-1,4 glycosidic linkages
AMYLOSE
α-1,4 glycosidic linkages as well as α-1,6 glycosidic linkages
AMYLOPECTIN
More highly branched than amylopectin but also has α-1,4 glycosidic linkages as well as α-1,6 glycosidic linkages
GLYCOGEN
Linear
Made up of β-glucose units with all glycosidic linkages in the 1, 4-position
Extensive hydrogen bonding between chains
Strength, rigidity
Insoluble
CELLULOSE
MAJOR FUNCTIONS OF CARBOHYDRATES
Energy Source
Energy Reserve (e.g. glycogen)
Precursor of other Biologically Important Molecules (e.g. anticoagulants, components of nucleic acids)
DIETARY FIBRE
Plant material
Cannot be digested by humans
Parts of fruits, vegetables, grains
May be digested by bacteria in gut
Cellulose
Lignin
Pectin
IMPORTANCE OF HIGH FIBRE DIET
Constipation and DiverticulosisIrritable bowel syndromeObesityCrohn´s DiseaseHaemorrhoids
READING AND QUESTIONS
Please read pages 331 to 334, all about carbohydrates.
Take your own notes.
Make a mind map.
Can you answer the questions in the orange boxes (B.3.1 etc) ?
Now answer questions 9 to 16 on page 359.