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15 Cards in this Set
- Front
- Back
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What is meant by secondary structure of protein |
- Folding of polypeptide chains into alpha helix |
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What is meant by tertiary structure of a protein/ enzyme |
- Further folding of the secondary structure |
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Explain why a protein with a tertiary structure is affected by a pH change . In your answer give group that is affected by lowering the pH stating what is formed |
- Changing pH affects the ionic charges on groups so by lowering pH -COO- can form -COOH |
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Explain why the curve of rate vs temperature for an enzyme rises and falls |
- as temperature rises particle more kinetic energy - more collisions have energy greater than the activation - graph falls because at high temperature intermolecular bonds - loss of active site |
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The main reaction sequence of an enzyme E with substrate S to form the product P can be represented as shown below - E +S ----> ES complex -----> EP complex -----> E + P When the substrate S concentration is high, state the order of reaction to the respect to substrate and explain |
- Zero order - all the active sites are full - all enzymes have combined with substrate molecules |
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Suggest one advantage of using enzymes over laboratory reagents to prepare organic compounds on a industrial scale |
- Reduces number of steps / Increases atom economy |
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Explain how colorimetery could be used to follow the change in concentration of iodine in an aqueous reactions in which only colour change is the conversion of colourless iodide ions to iodine solution. |
- use filter of complementary colour to iodine solution - zero the colorimeter with water - measure absorbance readings of standard solution of known concentration of (Iodine) - plot calibration readings of the reacting mixture at known times - convert absorbance readings to iodine concentration |
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Explain in terms of frequencies of light, why some transition metal in solution are coloured |
- Ions absorb specific wavelengths of visible light and transmits complementary colour |
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Describe how thin layer chromatography can be used to show a mixture of 3 different known organic compounds |
- Draw pencil-line near bottom of plate - place 1 drop of mixture and a drop of 3 the compounds on the line - Place plate in solvent, solvent level is below line - add lid - when solvent nears the top of plate, remove the plate - locate spots with UV light - compare heights/positions of spots from mixtures with 3 standard compounds |
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Describe how you would carry out titration to get one results |
- Fill burette with KMnO4 - Use graduated 25cm3 pipette for sodium ethanedioate - to place solution in flask and then acidify ( and warm flask) - then add KMnO4 solution slowly near end point (use a white tile) - Until permanent pink colour |
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What is the coordination number of Fe in the complex [Fe(H2O)6]3+ and what is the name of the shape of the complex? |
- coordination number of Fe = 6 , shape is octahedral |
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Describe and explain one method for protecting metal from corrosion |
- barrier protection e.g. paint or galvanising - protects copper reacting with oxygen and water - Or sacrificial protection: - coat with blocks of Mg or Zn |
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Explain why H2NCH2CH2NH2 is a bidentate ligand ? |
- it can donate both lone pairs of electrons - to form a dative covalent bond |
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[V(H2O)6]2+ can react with ammonia to form a new complex ion, name the type of reaction occurring |
- Ligand exchange |
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Concentrated hydrochloric acid is added to aqueous CU 2+ ions which causes a change in colour solution, Name the type of reaction and give formula |
- Ligand exchange - [CuCl4] 2- |
