I have answered some questions for our enzyme sac. Could someone pls check them and feel free to add anything.
1)How do enzymes catalyse reactions?Enzymes catalyse reactions by reducing the activation energy required for a reaction to proceed. The enzyme temporary binds with specific substrates and produces products.
2)Explain Lock and Key model and Induced fit model of enzyme action
Lock and key model- States that the active site & substrate are exactly complementary. Each enzyme is very specific to the substrate.
Induced fit model- Suggests that the enzyme can slightly modify the shape of the active site to accommodate the substrate. (More widely accepted)
3)How does temperature affect enzyme activity?Temperature increases the rate of reaction by increasing the kinetic energy so that more molecules collide more frequently. However, if the temperature exceeds the optimum temperature, the enzymes denature and the rate of reaction stops. If the temperature is below the optimum temp, there is not enough collisions and the rate of reaction decreases.
4)How does pH affect enzyme activity?All enzymes work at an optimum ph. By changing the pH, and increasing or lowering it too much, the enzyme could denature. As a result, the active site with permanently lose its shape, and the enzyme will not be able to conduct anymore reactions.
5)What is meant by the activation energy?
Activation energy is the energy required to start a reaction. Enzymes lower the activation energy.
6)How do enzymes affect activation energy
Enzymes lower the activation energy. (Please add info here-not a very good answer)
7)How does concentration affect enzyme activity?
An increased concentration of enzyme increases enzyme activity, as more enzymes will undergo reactions. A decreased concentration of enzyme will decrease enzyme activity. On the other hand, substrate concentration can also affect enzymes. High substrate concentrations mean enzymes will conduct reactions longer to break down all products. Low substrate concentrations means enzyme will conduct reactions quicker.
Endergonic/ Exergonic reactions
Anabolic/Endothermic – Build-up of molecules
-Requires energy
-6CO2+6H2OC6H12O6 + 6O2 (Photosynthesis)
Catabolic/ Exergonic- Break down of molecules
-Releases energy
-C6O12O6 + 6O2 6CO2 + 6H2O + ENERGY (Cellular respiration)
For your first answer, I'd add that it reduces activation energy by weakening bonds in the substrate molecule. Also, activation energy is the energy required for a reaction to begin not 'proceed'
Your second answer is spot on!
For your fourth answer, you could say 'altering' not changing
For your sixth answer, be a bit more specific - consider how activation energy is reduced?
I'd say something like "Enzymes weaken the bonds in the substrate/s molecule/s which in turn reduces the activation energy hence enabling the reaction to commence and proceed at a faster rate"
Hmm I don't know why anabolic reactions have been compared with endothermic reactions. You're being specific which is good but if you're describing it in general terms, then anabolic reactions are endergonic. Endothermic reactions are simply a category of endergonic reactions.
In regards to your description of an exergonic reaction, alongside referring to it as a decomposition reaction, also mention that it releases energy.
Hope this helped and please forgive me if I've made any mistakes.
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