- Static Rigid 1890 Inflexible Strong Daniel Koshland Complimentary Before Binding Not Static Flexible 1958 N 1 (115.82 KiB) Viewed 39 times
- Static Rigid 1890 Inflexible Strong Daniel Koshland Complimentary Before Binding Not Static Flexible 1958 N 2 (31.62 KiB) Viewed 39 times
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- Static Rigid 1890 Inflexible Strong Daniel Koshland Complimentary Before Binding Not Static Flexible 1958 N 3 (77.29 KiB) Viewed 39 times
*Static (rigid) *1890 "Inflexible /strong *Daniel Koshland *Complimentary before binding *Not static (flexible) *1958 *Not complimentary before binding *Explains why some enzymes can bind with a range of substrates with a similar shape *Proposes that non-complimentary enzyme and substrate molecules can bond together to catalyse a reaction due to the ability of the enzyme active site to change shape slightly to fit the substrate *Proposes that perfectly complimentary enzyme and substrate molecules bond together to bring about a catalysed reaction *Totally specificity for a single substrate [C] Using information from the diagrams of the two models and from the biology sessions, write down FOUR shared features (similarities). When choosing your similarities, consider the following factors: Activation energy, complexes formed, fate of the substrate(s), fate of the enzyme. Q7 (AC 3.2) Experiment to investigate the effect of different concentrations of catalase enzyme on the breakdown of hydrogen peroxide: Catalase is an enzyme which catalyses the breakdown of toxic hydrogen peroxide (the substrate) to harmless water and oxygen gas (the products). The oxygen can be seen as the production of small bubbles which can be captured by the addition of detergent to the test-tube. This experiment will investigate how changing the concentration of catalase affects the rate of breakdown of a fixed concentration of hydrogen peroxide. Catalase Water + Oxygen Hydrogen Peroxide Safety Ensure that safety glasses are worn for the duration of the practical. Hydrogen Peroxide: Irritant Catalase: Irritant Apparatus 10 boiling tubes Test-tube racks 5cm³ syringe or pipette 1cm³ syringe or pipette Catalase solutions [0.5% - 5% (w/v)] 3% (v/v) Hydrogen peroxide - Caution, use safety goggles when using. Teepol solution (detergent) Stopwatch and ruler Method 1 Draw an appropriate table to record the results and those of two others. Use these to calculate a mean. Complete this during the practical. 2 Label boiling tubes with the concentrations of catalase to be added, from 0.5% to 5% (w/v). 3 Fill each of the 10 boiling tubes with 5cm³ of hydrogen peroxide. 4 Add 5 drops of teepol solution to each tube. 5 Start with the tube labelled 0.5%. Add 1 cm³ of 0.5% catalase to the hydrogen peroxide. 6 Measure the height of the foam (in mm) after 30 seconds. 7 Repeat for the remaining catalase concentrations. 8 Clear away the apparatus carefully and wipe down the bench. 9 Use the mean results in your table to create a line graph
The tabulated and graphical results should display a trend. Explain the reason for this trend using collision theory. Remember to also submit the table of results and line graph to complete this work book. Additional Guidance All sources (including diagrams/photos) used must be referenced accurately using the Harvard system. You must reference in text and include a bibliography. In order to achieve grades higher than pass, you will need to include the following in your answers (for more specific guidance see also the section on grading information): Evidence of wider reading A range of examples A level of detail and depth exceeding that covered in classes The use of diagrams as well as written descriptions :(write your answer here)
Q6 (AC 3.1) [A] The diagrams below show two possible models to explain how enzymes catalyse chemical reactions in biological systems. State the name of each model in the space provided Model A > Name of model A: (write your answer here) 中 enzyme + substrate antering active site enzyme substrate complex enzymproduct complex enzyme product leaving active site Model B Products Substrate Active site Enzyme changes shape slightly as substrate binds 介 >> Name of model B::(write your answer here) Substrate entering the active site of the enzyme Enzyme/substrate complex Enzyme/product complex Products leaving the active site of the enzyme Use your knowledge gained during the biology sessions and from the diagrams previous, to choose appropriate statements from the list below to complete the table to contrast the two models of enzyme action. You must use each statement only ONCE: Feature Lock and key model Induced fit model Description of (write your answer here) the model Shapes of (write your answer here) molecules Nature of (write your answer here) bonding within the E-S complex Who proposed (write your answer here) each theory/model? Active site (write your answer here) behaviour Year (write your answer here) discovered Specificity of (write your answer here) enzyme for substrate "Flexible / weak "Emil Fischer