nutrients Flashcards
why do we need food?
- provide energy
- supply raw materials to make new protoplasm
- help us stay healthy
what are nutrients?
chemical substances in food that provide energy and materials needed by the body
what are the functions of water?
- solvent/medium in which chemical reactions take place
- essential component of cells’ protoplasm, tissue fluids, digestive juices and blood
- helps control body temperature via sweating
- helps transport dissolved susbtances around body
- essential for photosynthesis
- helps keep plant upright through turgor pressure in plant cells –> maintains cell structure
- needed for transport of mineral salts up the xylem
- needed for transport of food susbtances from leaves to other plant parts
water is lost when we breathe, sweat or urinate, amount of water needed:
- how active the person is
- how healthy
- environment conditions
what are carbonhydrates?
organic materials made up carbon, oxygen and hydrogen in the ratio of H:O, 2:1
what are the different types of the carbonhydrates?
- monosaccharides : simple sugars (glucose, fructose, galactose)
- disaccharides: double sugars (maltose, sucrose, lactose)
- polysaccharides: complex carbohydrates (starch, cellulose)
monosaccharides and dissacharides (except sucrose)= reducing sugars
how are dissacharides formed (reducing)?
- condensation reaction
- chemical reaction in which 2 simple molecules are joined together fo form a larger molecule with the removal of 1 water molecule
- when 2 glucose molecules join together via condensation reaction, maltose is formed
glucose + glucose –> maltose + water
what is the hydrolysis of disaccharides?
- hydrolysis is a reaction in which a water molecule is needed to break up a complex molecule into simple molecule
- double sugar can be spilt into two simple sugar molecules by hydrolysis in the presence of an enzyme
what is the test for reducing sugars?
- Benedict’s test
- to 2cm3 of sample, add equal volume of Benedicts solution
- shake well
- heat in boiling water bath for 5 minutes
- green, yellow or orange precipiate is seen (present)
- blue solution remains (absent)
what are complex carbohydrates??
- starch : storage form of carbo in plants. Found in sotrage organs in plants
- cellulose: cellulose cell wall protects plant cells. Serve as dietary fibre to prevent constipation
- glycogen: storage form of carbo in mammals. Digested to form glucose when needed
explain hydrolysis of starch?
- starch is digested into maltose molecules by amylase
- maltose molecules are broken down into glucose by maltose
what is the test for starch?
- iodine test
- to 2cm3 of sample, colouration is seen (present)
- brown colour remains (absent)
list the functions of carbohydrates?
- broken down in respiration to release energy for cell activities
- form supporting structures (cell wall)
- are converted to other organic compounds (amino acid)
- form part of nucleic acid
- used to synthesize lubricants
- used to synthesize nectar in flowers
what are fats?
organic compounds made up of carbon, oxygen and hydrogen in no fixed ratio
fat molecule : glycerol and fatty acid chains
hydrolysis of fats?
- broken down in simpler substances
what are the differences between saturated and unsaturated fats?
saturated :
- fatty acid chan in straight
- saturated fat molecule
- most solid at room temperature (butter)
unsaturated :
- fatty acid chain has kinks
- unsaturated fat molecule
- liquid at room temperature (olive oil)
what is the test for fats?
- Ethanol Emulsion Test
- to 2cm3 of sample, add equal volume of ethanol
- shake well
- add 2cm3 of water
- shake well
- white emulsion is seen (present)
- colourless solution remains (absent)
what are the functions of fats?
- a source and store of energy
- insulating material to prevent excessive heat loss
- solvent for fat source vitamins and some hormones
- form main part of cell membrane
- help reduce water loss from skin surface
what are proteins?
- organic compounds made up of oxygen, hydrogen, carbon and nitrogen
- each protein molecule is made up of smaller basic units called amino acids
what are proteins in depth?
- amino acids
- amino acids are building blocks of proteins
- peptide bonds link up amino acids to form polypeptide
- two or more polypeptide chains fold to form a three-dimensional molecule
what is the test for proteins?
- Biuret test
- to 2cm3 to 1cm3 sodium hydroxide
- shake well
- add copper sulfate solution dropwise
- shake well after each drop
- violet solution is seen (present)
- blue solution remains (absent)
what are the functions of proteins?
- synthesis of new protoplasm for grwoth and repair of worn-out cells
- synthesis of enzymes and some hormones
- synthesis of antibodies
