2354645
Description
Flashcards by mollie.dawson, updated more than 1 year ago
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Created by mollie.dawson
over 9 years ago
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| Question | Answer |
| What are enzymes? (3) | Globular proteins Have a specific tertiary structure Catalyse metabolic reactions in living organisms |
| What is a catalyst? | A substance which speeds up a chemical process without being used up in the reaction itself |
| Is enzyme action intracellular or extracellular? | Both |
| What type of protein is an enzyme? | Globular |
| What determines the active site? | Tertiary structure |
| What lowers the activation energy? | Formation of enzyme-substrate complex |
| How can activation energy be lowered? (2) | When two molecules are joined via enzyme Breakdown reaction via enzyme |
| How is activation energy lowered when two molecules are joined? | They attach to enzyme which holds them together - reducing repulsion effect |
| How is activation energy lowered in a breakdown reaction? | Fitting into the active site puts a strain on bonds, so molecule breaks easier |
| How does the induced fit model differ from the lock and key model? | Induced fit model incorporates that the enzyme-substrate complex changes shape slightly to fit |
| What affects rate of reaction? (4) | Temperature pH Enzyme concentration Substrate concentration |
| How does temperature affect rate of reaction? (4) | Higher temperature makes enzyme molecules vibrate more If temp goes above certain temperature, vibrations break some bonds which hold enzyme together Active site changes shape Enzyme is denatured |
| How does pH affect the rate of reaction? | Enzymes have an optimum pH Above & below optimum, H+ and OH- ions in acids and alkali's mess up ionic & hydrogen bonds that hold tertiary structure |
| What does catalase catalyse? | Breakdown of hydrogen peroxide into water and oxygen |
| What does Amylase catalyse? | Breakdown of starch to maltose, iodine detects starch |
| What does an inorganic cofactor do? | Help the enzyme and substrate to bind together |
| So are inorganic cofactors changed or used up in any way? | No |
| What are manganese ions? | Cofactors found in hydrolase |
| What are organic cofactors called? | Coenzymes |
| What do coenzymes do? | They act as carriers, moving chemical groups between different enzymes |
| Are coenzymes altered during reactions? | Yes, they're continually recycled |
| So what is a coenzyme? | An organic cofactor which participate in the reaction and changed by it, they move chemical groups between enzymes and are continually recycled during this process |
| Can enzyme activity be inhibited? | Yes |
| What is competitive inhibition? | Competitive inhibitor molecules have a similar shape to substrate, they compete with substrate molecules to bind to active site, block active site so no reaction |
| What is non-competitive inhibition? | Non-competitive molecules bind to enzyme away from its active site, causing active site to change shape, so substrate molecules can't bind to it |
| What type of bond creates an irreversible inhibitor? | Strong, covalent bond |
| What type of bond creates a reversible inhibitor? | Weak, hydrogen/ionic |
| What is a metabolic poison? | An enzyme inhibitor |
| What is cyanide an irreversible inhibitor of? | Cytochrome c oxidase, which catalyses respiration reactions |
| What does penicillin do? | Inhibits transpeptidase, which catalyses the formation of proteins in bacterial cell walls, weakening cell wall, Boom, bacterium has burst |
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