T2L10 enzymes Flashcards
What are enzymes
Biological Catalysts - proteins that speed up the reaction without being used up. They are specific to each reaction they catalyse
Draw and Label the Lock and Key model
https://docs.google.com/presentation/d/1UBoG09A_pC8vGtlbauLRVyBzaoHJB-JtN0ZVdaVJvSM/edit?usp=sharing
How do enzymes work
Lower the activation energy (minimum energy required to start the reaction
Name two ways that enzyme catalysed reactions can be measured
The rate at which the reactants are broken down and the rate at which the products are made
Name 4 factors that can alter the speed of the reaction
Temperature
Enzyme concentration
Substrate concentration
pH
What type of proteins are enzymes
Globular
What is optimum temperature
Optimum temperature is the temperature at which enzymes work best at (fast enough for collisions not too fast to denature). Each enzyme may have unique optimum temperatures but those in the body have an optimum temperature of 37.5 degrees approx
What is optimum pH
The pH at which the enzyme works best. Wrong pH can cause the enzyme to denature and stop working properly or at all
How do enzymes lower the activation energy
- Charged areas of the active site and substrate attract which causes the substrate to be held in a position that encourages the bonds to be broken
- The active site of the enzyme may contain amino acids with acidic side chains that cause acidic conditions to help the reaction take place
Describe the induced fit model
This theory suggests that the enzyme changes shape slightly when the substance enters the active site to help it fit more tightly. The enzymes are still specific
Explain how temperature increases the RoR up to a certain point
As temperature increases RoR increases up until a certain point.
An increase in temperature increases kinetic energy of the molecules so they collide more and to react the substrate particles must collide with the enzyme particles
However an increase in temperature also increases vibrational energy (esp enzymes) which puts strain on the bonds within. This means that more bonds are broken and the active site of the enzyme can change shape - the enzymes become less likely to function and become denatured and the reaction will slow
Explain how pH changes the rate of reaction
Every enzyme has an optimal pH range.
H+ and OH- ions are charhed so interact with the hydrogen and ionic bonds that hold the enzymes together . This is because they are attracted/repelled by the charges caused by the bonds.
The closer to the optimum pH the more accurate the shape is therefore the faster the rate of reaction. If the active site changes too much the enzyme will change shape and not function - denatured
Explain how substrate concentration affects rate of reaction
The more substrate molecules that there are the more molecules collide with the enzymes to react and form more of the product(s)
This only up until a certain point when the enzymes are saturated - there are not enough enzymes to match the increased substrate concentration so the enzymes are working at their maximum possible rate. This is where the enzymes have become the limiting factor
Explain how enzyme concentration affects rate of reaction
The more enzyme molecules that there are the more molecules collide with the substrate to react and form more of the product(s)
Draw the graphs for the affect of changing temperature, pH, enzyme conc and substrate conc
https://docs.google.com/presentation/d/1UBoG09A_pC8vGtlbauLRVyBzaoHJB-JtN0ZVdaVJvSM/edit#slide=id.g1c8b59393ab_0_0
