Enzymes worksheet B (temperature) - Q1b

Please be specific in your answer/ note the context of the question (i.e. NAME the enzyme and substrate if the question stem mentions them)

- D: Initially at very low temperature, the enzyme activity (rate of enzymatic reaction) is very low.
- E: This is due to the inactivation of the enzymes, and the low kinetic energies of both the substrate and enzyme molecules, leading to a low frequency of effective collisions between them, and hence reduced rate of formation of enzyme-substrate complexes and products. 

- D: As temperature increases to optimum, the enzyme activity (rate) doubles for every 10C increase in temperature (Q10), and eventually reaches a peak/maximum rate at the optimum temperature (65C). 
- E: Increased temperature increases the kinetic energies of both enzyme and substrate molecules which in turn, increases the frequency of effective collisions between them. As a result, more enzyme-substrate complexes and hence products are formed.

- D: As temperature increases to beyond optimum, the enzyme activity (rate) decreases.
- E: This is due to the excess heat increases the vibrations of atoms within enzyme and disrupts the intramolecular hydrogen bonds, ionic bonds, and hydrophobic/hydrophilic interactions stabilising the secondary and tertiary structures of the enzymes, causing it to unfold and loses its specific 3D configuration/conformation (enzyme denatures). Hence its active site loses its specific shape, causing the substrate to be unable to bind to it. Hence, less enzyme-substrate complexes and products are formed.

P.S. If you have any queries with regards to the 3 MCQs in this enzymes wksheet B, you can ask me under comments here, or during the next tutorial. Note that we will be working on the main enzymes tutorial next week so please complete it over the wkend (treat it as lecture test revision). I aim to finish Enzymes before I leave! Hope you have enjoyed and benefited from my lessons. Don't miss me.. HAHA! See you next week! :)