Chp 4 Nutrients

Carbohydrates

food test

reducing sugar

Description:
add an equal volume of Benedict's solution
shake and then heat in a beaker of hot water

positive result:
solution turns orange/yellow/brick-red

negative result:
solution remains blue

starch test

Description:
add a few drops of iodine to a sample

positive result:
solution turns blue black

negative result:
solution remains brown/yellow

molecule

monosaccharides
basic unit(s)

glucose

fructose

galactose

general formula:
CmH2nOn

disaccharides
intermidiate molecule(s)

maltose

lactose

sucrose

polysaccharides
macromolecules(s)

starch

cellulose

glycogen

Increasing order of complexity:
monosaccharide -> disaccharides -> polyssacharides

functions

source of energy

form suppoting structures

cellulose cell walls

converted to other organic compounds

amino acids

fats

formation of deoxyribonucleic acid

synthesize lubricants

water

molecule

hydrogen, oxygen

H2O

functions

solvent for chemical reactions

key component of transport

need to control body temperature

essential for chemical reaction

hydrolysis

photosynthesis

fats

food test

Description:
add 2cm3 of ethanol
shake mixture thoroughly
add same amount of water

Positive result:
cloudy white emulsion form

Negative result:
remains clear & colourless

molecule

basic unit(s)

carbon, hydrogen, oxygen

less O:H than carbohydrates

general formula

saturated fats:
CnH2nO2

unsaturated fats:
-

broken down to

1 glycerol

3 fatty acid molecule

Increasing order of complexity:
glycerol + fatty acids -> fats

functions

efficient source & storage of energy

insulating material

solvent for fat-soluble solution

vitamins

sex hormones

related hormones

constituent of protoplasm

means to restrict water loss from skin surface

oily secretion by sebaceous glands in skin forms thin layer over surface

reduces rate of water evaporation & heat loss

proteins

food test

Description:
add 2cm3 of sodium hydroxide
shake mixture
add 1% copper sulphate solution, drop by drop
shake after drop

Positive result:
solution turns violet

Negative result:
solution remains blue

molecule

basic unit(s)

carbon

oxygen

hydrogen

nitrogen

often

sulphur

phosphorus

amino acids

general formula

NH2

CH

COOH

R

Increasing order of complexity:
amino acids -> polypeptides -> proteins

functions

essential for protoplasm synthesis

used for enzyme & hormone synthesis

antibodies formation to combat diseases

source of energy