Enzymes

1. At higher substrate concentrations, increasing the amount of substrate cannot increase the rate of reaction as active sites of enzyme molecules are _________.
4. enzymes are biological catalysts that speed up the rate of chemical reactions by lowering the __________ ______ of a chemical reaction, without being chemically altered in the reaction
5. As temperature increases beyond optimum temperature, enzyme is _________. The enzyme loses its 3D shape and active site is unable to bind to the substrate. Rate of reaction thus decreases.
6. the shape of the substrate is _____________ to the shape of the active site of the enzyme
7. Reaction rate is its maximum at enzyme _______ temperature/pH.
9. the part of an enzyme has a specific shape into which the substrate(s) fit exactly
11. the substrate binds to the active site of the enzyme, forming an ______-_________ _______

1. enzymes are required in _____ _______ because they remain chemically unchanged in the reactions they catalyse and can be reused
2. in the ‘____ ___ ___’ hypothesis, the substrate is the “key”, while the enzyme is the “lock”
3. Denaturation is ____________ even when temperature is lowered. At extremely high temperatures, the enzyme is completely denatured and the rate of reaction drops to zero.
8. As temperature increases, enzyme and substrate gain _______ ______ and they collide more often, increasing the formation of enzyme substrate complex thus increase rate of reaction. Rate of reaction doubles with every 10°C rise in temperature.
10. At low temperatures, enzymes are ________ and the rate of reaction is low. Substrate and enzyme molecules have little kinetic energy, hence the frequency of collision is low. In addition, most substrate molecules do not contain sufficient energy to overcome the activation energy required to start a reaction.