Biology- Organic molecules and food tests 0.0 / 5 ? BiologyOrganic molecules and food testsIGCSECIE Created by: KitsuneCreated on: 04-07-16 03:46 What do organisms need organic molecules for? For energy and raw materials 1 of 38 What are the 4 main groups of organic chemicals used by living things? Carbohydrates, proteins, lipids and nucleic acids 2 of 38 What is metabolism? The sum of all chemical reactions in cells 3 of 38 By what process are larger molecules broken down into smaller ones with the use of water? Hydrolysis 4 of 38 By what process are large molecules built up from smaller ones by the removal of water? Condensation 5 of 38 What are carbohydrates made out of? Simple repeating sugars called saccharides 6 of 38 What are the simplest carbohydrates? Monosaccharides 7 of 38 Gives an example of a monosaccharide Glucose 8 of 38 What do monosaccharides do? They are the main source of energy 9 of 38 Give an example of a disaccharide Sucrose 10 of 38 What do monosaccharides make up? Polysaccharides 11 of 38 Is glucose soluble? Yes 12 of 38 What is made out of glucose? Starch and glycogen 13 of 38 Why are starch and glycogen good stores of energy? They are insoluble 14 of 38 What important structure can polysaccharides form? Cellulose cell wall 15 of 38 What are lipids made out of? 3 molecules of fatty acids with 1 molecule of glycerol 16 of 38 What are the uses of lipids? Insulation, storing, vitamin absorption, protection 17 of 38 If fats and oils are insoluble in water, what are they good for? Excellent stores of energy and barriers between cells and their environment 18 of 38 What are proteins made up of? Amino acids 19 of 38 How many amino acids are there? 20, 9 of them are essential 20 of 38 What determines the shape of a protein molecule? The sequence of amino acids 21 of 38 What depends on the shape of the protein? Its function 22 of 38 Amino acids=> ... => ... => Protein Peptide, polypeptide 23 of 38 What chemical elements are present in amino acids? Carbon, hydrogen, oxygen, nitrogen, sometimes sulphur 24 of 38 Why are amino acids easily transported? They are soluble 25 of 38 What are the uses of proteins? Growth, repair, tissue development 26 of 38 What is the structure of nucleic acids in DNA? Two strands coiled together to form a double helix 27 of 38 How are the chemicals in nucleic acids called? Bases 28 of 38 How are the bases cross-linked? AT, CG 29 of 38 What does the DNA do? Passes on the genetic information 30 of 38 Why is water so important? It is a solvent in organisms in digestion, excretion and transport 31 of 38 Give two specific use of a protein Antibodies, enzymes 32 of 38 What is the test for reducing sugars? What is the colour change? Benedict's test, from blue to brick-red 33 of 38 What is the test for starch? What is the colour change? Iodine test, from orange to black, dark blue 34 of 38 What is the test for proteins? What is the colour change? Biuret test, from blue to mauve 35 of 38 What is the test for lipids? What is the observable change? Emulsion/ Ethanol test, a cloudy precipitate forms 36 of 38 What is the test for Vitamin C? What is the colour change? DCPIP test, from blue to colourless 37 of 38 Why are food tests useful? They give a good visual result 38 of 38
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