Proteins 0.0 / 5 ? BiologyBiological molecules, organic chemistry and biochemistryASAQA Created by: ellen duckersCreated on: 19-02-14 20:00 what is the biuret test used to determine? whether a protein is present - it will go purple. 1 of 26 what are AAs made up of? carbon, hydrogen, oxygen, nitrogen 2 of 26 what attaches to the central carbon atom? -H -NH2 (amino) -COOH (carboxyl) -variable R group 3 of 26 give 3 examples of AAs. phenylalanine, aspartate, tyrosine 4 of 26 what are polypeptides? chains of AAs joined by polypeptide bonds between the carbon atom of one and the nitrogen atom of another 5 of 26 what happens when two AAs join? a dipeptide is formed 6 of 26 what process is this? polymerisation 7 of 26 what is there at each end? -a free amino group. -a free carboxyl group. 8 of 26 what do polypeptides fold to form? the 3D structure of working proteins 9 of 26 what does the primary structure determine? the ultimate shape thus function of the protein. 10 of 26 what does one change in the sequence of AAs lead to? a change in the proteins shape so that it can no longer carry out its function correctly. 11 of 26 what is the secondary protein structure? the shape formed by the AA chain when it first twists 12 of 26 how is it stabilised? by the formation of hydrogen bonds 13 of 26 what shapes could it be? -alpha helix > spiral shape. -beta pleated sheet > zig zags back and forth 14 of 26 what is the tertiary structure? the second level of folding that gives a complex, 3D structure. 15 of 26 how is the structure maintained? by hydrogen bonds and disulphide bridges 16 of 26 what does the 3D shape do? makes each structure distinctive allowing it to be recognised by other molecules. 17 of 26 where does the quaternary structure occur? in proteins that have more than one polypeptide chain and/or a non-protein group 18 of 26 give an example. haemoglobin contains haem which is an iron-containing group 19 of 26 what do globular proteins do? carry out metabolic functions 20 of 26 how is their specific 3D shape essential to their role? it makes the proteins specific to particular substrates/antigens/ions/molecules/receptors 21 of 26 what roles to fibrous proteins have? they have structural roles 22 of 26 why? they look like ropes and are composed of many polypeptide chains which makes them strong. 23 of 26 give examples. -collagen>bones. -keratin>hair. -tubulin>cytoskeleton in cells. -actin>muscle. 24 of 26 what happens if a gene mutates? the function of the protein is non-existant 25 of 26 why? the sequence of AAs has changed 26 of 26
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