Factors affecting enzyme activity PDF

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Notes on Biology A Level OCR A...

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Factors affecting enzyme activity

Enzymes and Temperature • As temperature increases, kinetic energy and the number of successful collisions increase reaction rate • Optimal temperature is when enzyme activity is at its highest • Temperature is too high. , the shake breaks the bonds that hold the enzyme together. Denatured enzyme (irreversibly altered to form an active site) • Enzyme activity decreased. Temperature coefficient Q10 • The Q10 value for a reaction shows how much the reaction rate changes as the temperature increases by 10oC • At the pre-optimal temperature, a Q10 value of 2 means speed The temperature doubles for every 10 ° C increase. 3 means he tripled. • Most enzymes have a Q10 of 2

Calculate Q10 Q10 = rate at higher temperatures rate at lower temperatures Example: The rate of a given reaction is 10 units / min at 20 ° C and 24 units / min at 30 ° C. What is his Q10?

Q10 = rate at higher temperatures ÷ rate at lower temperatures = 24 ÷ 10 = 2.4 Enzymes and pH • pH optimum - pH at which enzymes work best at • When When moving towards at the optimum pH, enzymes begin to denature and enzyme activity decreases. • The H + and OH- ions present in acids and alkalis break the ionic and H bonds which hold in place the tertiary structure of the enzyme...