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Biological molecules - Coggle Diagram
Biological molecules
carbohydrates
contain: carbon, hydrogen and oxygen
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disaccharides: two simple sugar molecules joined together. For example sucrose and maltose. They are insoluble and sweet
polysaccharides: many simple sugar molecules joined together. For example cellulose, starch and glycogen. They are insoluble and sweet
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testing for reducing sugar: use Benedicts tests. Add Benedic solution and then heat it. Positive result will produce brick-red colour, negative result will remain blue
testing for starch: add iodine solution. Positive result blue-black colour, negative result remains oragnge-brown
fats
contain: carbon, hydrogen and oxygen
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functions of fats: storage of energy, insulation, making cell membrane
test for fats: use ethanol emulsion test. Add ethanol, then water. Positive result causes an emulsion that looks white and opaque like milk. Negative result remains transparent
proteins
contain: carbon, hydrogen, oxygen, nitrogen and some sulfur
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function of proteins: making cells, enzymes, haemoglobin, also used for energy
test for protein: use the biruet test. Add water dilute copper sulfate solution and dilute potassium hydroxide solution. Positive result becomes purple, negative result stays blue
how enzymes work
the substance fits into the active site of the enzyme, forming an enzyme-substrate complex
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enzymes are specific, each king of enzyme will only catalyse one kind of chemical reaction
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water
water is an important solvent. Metabolic reactions can only take place if the chemicals that are reacting are dissolved in water.
Catalyst
a substance that increases the rate of a chemical reaction and is not changed by the reaction, so they can be used over and over again.
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