Core component 4 - Factors Effecting Enzyme Action Flashcards
Describe the graph of temperature against rate of reaction
The rate of reaction increases as temperature increases, steadily from 0 degrees Celsius up to 40 degrees Celsius where it reaches its optimum and after 40 Celsius the rate of reaction drops rapidly up to 55 Celsius.
Why does the rate of reaction increase as temperature increases?
As temperature increases, kinetic energy increases, this causes the enzyme and the substrate to move faster and therefore there are more collisions and more enzyme substrate complexes formed.
Why does the rate of reaction decrease after 40 degrees Celsius?
When temperature gets above 40 degrees this causes the enzyme to denature and it breaks the hydrogen bonds which hold the 3-D shape together meaning the substrate can no long fit in the active site
Explain why the rate of reaction is low at very low temperatures?
The enzyme is inactivated due to it having a very low kinetic energy
In terms of levels of structure what changes when an enzyme denatures?
It’s primary structure, the order of amino acids stays the same however it’s secondary structure and tertiary structure are effected.
Describe the ph against rate of reaction graph
From 3-7 as PH increases so does the rate of reaction, 7 being the optimum PH and then from 7–11 PH as it increases the rate of reaction decreases
Explain the PH against rate of reaction graph
Most enzymes have an optimum temperature where the rate of the reaction is highest and small changes around the optimum cause reversible changes but extremes of PH cause the enzyme to denature due to the disruption to the hydrogen bonds and 3-D structure (active site) and therefore no enzyme substrate complexes can be formed.
What happens to enzymes at low PH?
Excess H+ ions are attracted to negative charges and neutralise them which effects bonds in enzyme.
What happens to enzymes at a high PH?
Excess OH- ions neutralise the positive charges which causes changes in bonds and therefore structure.
Describe the substrate concentration against rate of reaction graph
As substrate concentration increases rate of reaction increases and they are directionally proportional however towards the end the line begins to plateau
Explain the substrate concentration against rate of reaction graph
As the amount of substrate increases, more active sites can be filled and therefore more enzyme substrate complexes can be formed. However, as even more substrate is added the rate cannot increase anymore as all active sights are saturated meaning that another factor like temperature is the limiting factor
Describe the relationship between enzyme concentration and rate of reaction
If temperature and PH are optimal and there is an excess of substrate the rate of reaction is directly proportional to the enzyme concentration
What is the importance of a buffer?
They maintain a constant pH.
