Biological molecules 0.0 / 5 ? BiologyBiological moleculesASAQA Created by: amm242Created on: 17-05-18 11:23 What is a monosaccharide? Soluble substances which are monomers of carbohydrates eg. glucose, fructose and galactose 1 of 30 How do you test for reducing sugars? Benedict's reagent is heated with a reducing sugar to produce a brick red precipitate 2 of 30 What is a disaccharide? Monosaccharides are joined in condensation reactions to form glycosidic bond 3 of 30 Give example of disaccharides Maltose (glucose+glucose), Lactose (glucose+galactose), Sucrose (glucose+fructose) 4 of 30 How do you test non reducing sugars? If Benedict's test does not turn red, add dilute HCl to new sample and heat, then add NaHCO3 to neutralise. Should now turn Benedict's red 5 of 30 What is a polysaccharide? Insoluble polymers made up of many monosaccharides 6 of 30 How do you test for starch? Drop starch solution onto spotting tile and add potassium iodide which turns blue-black 7 of 30 Describe the structure of starch Alpha glucose, branched or unbranched chains (compact coil) 8 of 30 How is starch adapted to store energy? Insoluble so doesnt affect water potential, too large to diffuse, compact, branched form hydrolysed quickly 9 of 30 Describe the structure of glycogen Alpha glucose, short, highly branched chains 10 of 30 How is glycogen adapted to store energy? Insoluble so doesnt draw in water, doesnt diffuse, compact, highly branched allowing quick hydrolysis 11 of 30 Describe the structure of cellulose Beta glucose, straight unbranched chains running parallel with H bonds inbetween 12 of 30 How is cellulose adapted to provide support and rigidity? Straight unbranched chains, H bonds between chains, form microfibrils 13 of 30 What is the role of lipids? Cell membranes, source of energy, waterproofing, insulation, protection 14 of 30 Describe a lipid Contain C, H & O, insoluble in water, soluble in organic solvents 15 of 30 Describe the structure of triglycerides Three fatty acids attached to one glycerol with ester bond formed by condensation reaction 16 of 30 What is the structural difference between saturated & unsaturated fats? Saturated = no double C-C bonds, Unsaturated = double C=C bond 17 of 30 What does mono-unsaturated mean? More than one double bond is present 18 of 30 How are triglycerides adapted to their functions? Lots of energy storing C-H bonds, low mass:energy, non-polar so dont affect osmosis 19 of 30 What is a phospholipid? No glycerol and one fatty acid is replaced by a phosphate molecule. They have hydrophilic heads and hydrophobic tails 20 of 30 How are phospholipids adapted to their functions? Form hydrophobic barrier between inside and outside of cell, form glycolipids for cell recognition, hold water at cell membrane 21 of 30 Describe the structure of an amino acid? Amino group (NH2), Carboxyl group (COOH), H atom, variable R group 22 of 30 What is the primary structure of proteins? Amino acids joined by peptide bonds to form polypeptide chains. Sequence is determined by DNA 23 of 30 What is the secondary structure of proteins? Hydrogen bonds form between H and O forming alpha helix or beta pleated sheet 24 of 30 What is the tertiary structure of proteins? Further twisting of helix by disulfide bridges, ionic & H bonds to form specific 3D structure 25 of 30 What is the quaternary structure of proteins? Lots of polypeptide chains linked, possibly with non-protein groups 26 of 30 How do you test for proteins? Biuret test: equal amounts of copper sulfate and sodium hydroxide mixed with sample turns purple 27 of 30 What do globular proteins do? Carry out metabloic functions eg. enzymes & haemoglobin 28 of 30 What do fibrous proteins do? Have structural functions eg. collagen 29 of 30 Describe the strcuture of fibrous proteins? Long chains running parallel to each other linked by cross bridges and wound tightly around each other 30 of 30
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