4362357
Description
Flashcards by Megan Falconer, updated more than 1 year ago
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Created by Megan Falconer
about 8 years ago
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| Question | Answer |
| 1 What is activation energy? | Activation energy is the energy needed to either make or break chemical bonds in the reactant chemicals (enzyme substrates). |
| 2 What happens when the enzymes have absorbed sufficient energy? | When the enzymes have absorbed sufficient energy (e.g heat), chemical bonds break and the reactants reach an unstable transition state. |
| 3 Draw a reaction pathway for activation energy. | |
| 4 What is a catalyst? | A catalyst is a substance which can speed up a reaction. Enzymes are biological catalysts. |
| 5 What happens when a catalyst is present during a reaction? | There is lower activation energy required. They speed up the rates of reaction. They remain unchanged after the reactions are complete. |
| 6 What are biological catalysts made up of? | Biological catalysts are made up of proteins. |
| 7 What is the importance of enzymes? | Enzymes allow reactions to occur very quickly and at temperatures low enough to sustain life (5-40c). |
| 8 What would happen if there was an absence of enzymes? | In the absences of enzymes, biochemical pathways such as respiration and photosynthesis would proceed so slowly that life as we know it would cease to exist. |
| 9 Where is the active site? | Enzymes have a groove or hollow on their surface where the active site is located. |
| 10 What is the shape of the active site determined by? | The shape of this is determined by the chemical structure and bonding between amino acids in the polypeptide chain that make it up. |
| 11 What does the term specific mean in relation to enzymes? | The enzyme acts on only one type of substance - its substrate - whose molecules exactly fit the enzymes active site. The molecules of the substrate are complementary to the enzymes active site for which the show an affinity. |
| 12 What structure is flexible and dynamic? | The enzymes active site. |
| 13 What is an induced fit? | When a substrate enters the active site, the shape of the enzyme and active site change slightly, making the active site fit very closely round the substrate molecule. |
| 14 What happens when you increase the substrate concentration? | As we increase the substrate concentration, more enzymes/substrate complexes can form. This speeds up the reaction rate. |
| 15 What happens when there is no excess enzymes left? | When the enzyme is no longer in excess, the number of complexes is at a maximum. |
| 16 What happens to the rate of reaction when there are no excess enzymes? | The rate of reaction levels off and remains constant no matter how much more substrate is added. |
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