1.8: The factors affecting enzyme action Flashcards
Before considering how pH and temperature affect enzymes, it is worth bearing in mind that for an enzyme to work, it must what?
Before considering how pH and temperature affect enzymes, it is worth bearing in mind that for an enzyme to work, it must:
- Come into physical contact with its substrate
- Have an active site that fits the substrate
Before considering how pH and temperature affect enzymes, it is worth bearing in mind that for an enzyme to work, it must come into physical contact with its substrate and have an active site that fits the substrate.
Almost all factors that influence the rate at which an enzyme works do so by affecting one or both of the above.
In order to investigate how enzymes are affected by various factors, we need to be able to do what?
In order to investigate how enzymes are affected by various factors, we need to be able to measure the rate of the reactions they catalyse
Measuring enzyme-catalysed reactions:
To measure the progress of an enzyme-catalysed reaction, we usually do what?
To measure the progress of an enzyme-catalysed reaction, we usually measure its time-course
Measuring enzyme-catalysed reactions:
To measure the progress of an enzyme-catalysed reaction, we usually measure its time-course, that is how long it takes for what?
To measure the progress of an enzyme-catalysed reaction, we usually measure its time-course, that is how long it takes for a particular event to run its course
Measuring enzyme-catalysed reactions:
To measure the progress of an enzyme-catalysed reaction, we usually measure its time-course, that is how long it takes for a particular event to run its course.
The how many changes most frequently measured are what?
The 2 changes most frequently measured are the:
- Formation of the products of the reaction
- Disappearance of the substrate
Measuring enzyme-catalysed reactions:
To measure the progress of an enzyme-catalysed reaction, we usually measure its time-course, that is how long it takes for a particular event to run its course.
The 2 changes most frequently measured are the formation of the products of the reaction, for example what, and the disappearance of the substrate?
The 2 changes most frequently measured are the:
- Formation of the products of the reaction, for example the volume of oxygen produced when the enzyme catalase acts on hydrogen peroxide
- Disappearance of the substrate
Measuring enzyme-catalysed reactions:
To measure the progress of an enzyme-catalysed reaction, we usually measure its time-course, that is how long it takes for a particular event to run its course.
The 2 changes most frequently measured are the formation of the products of the reaction, for example the volume of oxygen produced when the enzyme catalase acts on hydrogen peroxide, and the disappearance of the substrate, for example what?
The 2 changes most frequently measured are the:
- Formation of the products of the reaction, for example the volume of oxygen produced when the enzyme catalase acts on hydrogen peroxide
- Disappearance of the substrate, for example the reduction in concentration of starch when it is acted upon by amylase
One graph showing a curve from the bottom going up to the top right and another graph showing a curve from the top to the bottom right.
Although the graphs differ, the explanation for the shapes is the same:
At first, there is what?
At first there is:
1. A lot of substrate
,but
2. No product
One graph showing a curve from the bottom going up to the top right and another graph showing a curve from the top to the bottom right.
Although the graphs differ, the explanation for the shapes is the same:
At first, there is a lot of substrate, but no product.
It is very easy for substrate molecules to do what?
It is very easy for substrate molecules to come into contact with the empty active sites on the enzyme molecules
One graph showing a curve from the bottom going up to the top right and another graph showing a curve from the top to the bottom right.
Although the graphs differ, the explanation for the shapes is the same:
At first, there is a lot of substrate, but no product.
It is very easy for substrate molecules to come into contact with the empty active sites on the enzyme molecules.
All enzyme active sites are what at any given moment?
All enzyme active sites are filled at any given moment
One graph showing a curve from the bottom going up to the top right and another graph showing a curve from the top to the bottom right.
Although the graphs differ, the explanation for the shapes is the same:
At first, there is a lot of substrate, but no product.
It is very easy for substrate molecules to come into contact with the empty active sites on the enzyme molecules.
All enzyme active sites are filled at any given moment and the substrate is what?
All enzyme active sites are filled at any given moment and the substrate is rapidly broken down into its products
One graph showing a curve from the bottom going up to the top right and another graph showing a curve from the top to the bottom right.
Although the graphs differ, the explanation for the shapes is the same:
At first, there is a lot of substrate, but no product.
It is very easy for substrate molecules to come into contact with the empty active sites on the enzyme molecules.
All enzyme active sites are filled at any given moment and the substrate is rapidly broken down into its products.
The amount of substrate does what as it is broken down?
The amount of substrate decreases as it is broken down
One graph showing a curve from the bottom going up to the top right and another graph showing a curve from the top to the bottom right.
Although the graphs differ, the explanation for the shapes is the same:
At first, there is a lot of substrate, but no product.
It is very easy for substrate molecules to come into contact with the empty active sites on the enzyme molecules.
All enzyme active sites are filled at any given moment and the substrate is rapidly broken down into its products.
The amount of substrate decreases as it is broken down, resulting in what?
The amount of substrate decreases as it is broken down, resulting in an increase in the amount of product
One graph showing a curve from the bottom going up to the top right and another graph showing a curve from the top to the bottom right.
Although the graphs differ, the explanation for the shapes is the same:
At first, there is a lot of substrate, but no product.
It is very easy for substrate molecules to come into contact with the empty active sites on the enzyme molecules.
All enzyme active sites are filled at any given moment and the substrate is rapidly broken down into its products.
The amount of substrate decreases as it is broken down, resulting in an increase in the amount of product.
As the reaction proceeds, there is what?
As the reaction proceeds, there is:
- Less and less substrate
- More and more product
One graph showing a curve from the bottom going up to the top right and another graph showing a curve from the top to the bottom right.
Although the graphs differ, the explanation for the shapes is the same:
At first, there is a lot of substrate, but no product.
It is very easy for substrate molecules to come into contact with the empty active sites on the enzyme molecules.
All enzyme active sites are filled at any given moment and the substrate is rapidly broken down into its products.
The amount of substrate decreases as it is broken down, resulting in an increase in the amount of product.
As the reaction proceeds, there is less and less substrate and more and more product.
It becomes what for the substrate molecules to do what?
It becomes difficult for the substrate molecules to come into contact with the enzyme molecules
One graph showing a curve from the bottom going up to the top right and another graph showing a curve from the top to the bottom right.
Although the graphs differ, the explanation for the shapes is the same:
At first, there is a lot of substrate, but no product.
It is very easy for substrate molecules to come into contact with the empty active sites on the enzyme molecules.
All enzyme active sites are filled at any given moment and the substrate is rapidly broken down into its products.
The amount of substrate decreases as it is broken down, resulting in an increase in the amount of product.
As the reaction proceeds, there is less and less substrate and more and more product.
Why does it become difficult for the substrate molecules to come into contact with the enzyme molecules?
It becomes difficult for the substrate molecules to come into contact with the enzyme molecules, because:
- There are fewer substrate molecules
- Also the product molecules may ‘get in the way’ of substrate molecules and prevent them from reaching an active site
One graph showing a curve from the bottom going up to the top right and another graph showing a curve from the top to the bottom right.
Although the graphs differ, the explanation for the shapes is the same:
At first, there is a lot of substrate, but no product.
It is very easy for substrate molecules to come into contact with the empty active sites on the enzyme molecules.
All enzyme active sites are filled at any given moment and the substrate is rapidly broken down into its products.
The amount of substrate decreases as it is broken down, resulting in an increase in the amount of product.
As the reaction proceeds, there is less and less substrate and more and more product.
It becomes difficult for the substrate molecules to come into contact with the enzyme molecules, because there are fewer substrate molecules and also the product molecules may ‘get in the way’ of substrate molecules and prevent them from reaching an active site.
It therefore takes longer for what?
It therefore takes longer for the substrate molecules to be broken down by the enzyme
One graph showing a curve from the bottom going up to the top right and another graph showing a curve from the top to the bottom right.
Although the graphs differ, the explanation for the shapes is the same:
At first, there is a lot of substrate, but no product.
It is very easy for substrate molecules to come into contact with the empty active sites on the enzyme molecules.
All enzyme active sites are filled at any given moment and the substrate is rapidly broken down into its products.
The amount of substrate decreases as it is broken down, resulting in an increase in the amount of product.
As the reaction proceeds, there is less and less substrate and more and more product.
It becomes difficult for the substrate molecules to come into contact with the enzyme molecules, because there are fewer substrate molecules and also the product molecules may ‘get in the way’ of substrate molecules and prevent them from reaching an active site.
It therefore takes longer for the substrate molecules to be broken down by the enzyme and so what slows?
It therefore:
- Takes longer for the substrate molecules to be broken down by the enzyme
- So its rate of disappearance slows
One graph showing a curve from the bottom going up to the top right and another graph showing a curve from the top to the bottom right.
Although the graphs differ, the explanation for the shapes is the same:
At first, there is a lot of substrate, but no product.
It is very easy for substrate molecules to come into contact with the empty active sites on the enzyme molecules.
All enzyme active sites are filled at any given moment and the substrate is rapidly broken down into its products.
The amount of substrate decreases as it is broken down, resulting in an increase in the amount of product.
As the reaction proceeds, there is less and less substrate and more and more product.
It becomes difficult for the substrate molecules to come into contact with the enzyme molecules, because there are fewer substrate molecules and also the product molecules may ‘get in the way’ of substrate molecules and prevent them from reaching an active site.
It therefore takes longer for the substrate molecules to be broken down by the enzyme and so its rate of disappearance slows.
Consequently, what also slows?
Consequently, the rate of formation of product also slows
One graph showing a curve from the bottom going up to the top right and another graph showing a curve from the top to the bottom right.
Although the graphs differ, the explanation for the shapes is the same:
At first, there is a lot of substrate, but no product.
It is very easy for substrate molecules to come into contact with the empty active sites on the enzyme molecules.
All enzyme active sites are filled at any given moment and the substrate is rapidly broken down into its products.
The amount of substrate decreases as it is broken down, resulting in an increase in the amount of product.
As the reaction proceeds, there is less and less substrate and more and more product.
It becomes difficult for the substrate molecules to come into contact with the enzyme molecules, because there are fewer substrate molecules and also the product molecules may ‘get in the way’ of substrate molecules and prevent them from reaching an active site.
It therefore takes longer for the substrate molecules to be broken down by the enzyme and so its rate of disappearance slows.
Consequently, the rate of formation of product also slows.
Both graphs do what?
Both graphs ‘tail off’
One graph showing a curve from the bottom going up to the top right and another graph showing a curve from the top to the bottom right.
Although the graphs differ, the explanation for the shapes is the same:
At first, there is a lot of substrate, but no product.
It is very easy for substrate molecules to come into contact with the empty active sites on the enzyme molecules.
All enzyme active sites are filled at any given moment and the substrate is rapidly broken down into its products.
The amount of substrate decreases as it is broken down, resulting in an increase in the amount of product.
As the reaction proceeds, there is less and less substrate and more and more product.
It becomes difficult for the substrate molecules to come into contact with the enzyme molecules, because there are fewer substrate molecules and also the product molecules may ‘get in the way’ of substrate molecules and prevent them from reaching an active site.
It therefore takes longer for the substrate molecules to be broken down by the enzyme and so its rate of disappearance slows.
Consequently, the rate of formation of product also slows.
Both graphs ‘tail off.’
The rate of reaction continues to do what?
The rate of reaction continues to slow
One graph showing a curve from the bottom going up to the top right and another graph showing a curve from the top to the bottom right.
Although the graphs differ, the explanation for the shapes is the same:
At first, there is a lot of substrate, but no product.
It is very easy for substrate molecules to come into contact with the empty active sites on the enzyme molecules.
All enzyme active sites are filled at any given moment and the substrate is rapidly broken down into its products.
The amount of substrate decreases as it is broken down, resulting in an increase in the amount of product.
As the reaction proceeds, there is less and less substrate and more and more product.
It becomes difficult for the substrate molecules to come into contact with the enzyme molecules, because there are fewer substrate molecules and also the product molecules may ‘get in the way’ of substrate molecules and prevent them from reaching an active site.
It therefore takes longer for the substrate molecules to be broken down by the enzyme and so its rate of disappearance slows.
Consequently, the rate of formation of product also slows.
Both graphs ‘tail off.’
The rate of reaction continues to slow until what?
The rate of reaction continues to slow until there is so little substrate that any further decrease in its concentration cannot be measured
One graph showing a curve from the bottom going up to the top right and another graph showing a curve from the top to the bottom right.
Although the graphs differ, the explanation for the shapes is the same:
At first, there is a lot of substrate, but no product.
It is very easy for substrate molecules to come into contact with the empty active sites on the enzyme molecules.
All enzyme active sites are filled at any given moment and the substrate is rapidly broken down into its products.
The amount of substrate decreases as it is broken down, resulting in an increase in the amount of product.
As the reaction proceeds, there is less and less substrate and more and more product.
It becomes difficult for the substrate molecules to come into contact with the enzyme molecules, because there are fewer substrate molecules and also the product molecules may ‘get in the way’ of substrate molecules and prevent them from reaching an active site.
It therefore takes longer for the substrate molecules to be broken down by the enzyme and so its rate of disappearance slows.
Consequently, the rate of formation of product also slows.
Both graphs ‘tail off.’
The rate of reaction continues to slow until there is so little substrate that any further decrease in its concentration cannot be measured.
The graphs do what?
The graphs flatten out
One graph showing a curve from the bottom going up to the top right and another graph showing a curve from the top to the bottom right.
Although the graphs differ, the explanation for the shapes is the same:
At first, there is a lot of substrate, but no product.
It is very easy for substrate molecules to come into contact with the empty active sites on the enzyme molecules.
All enzyme active sites are filled at any given moment and the substrate is rapidly broken down into its products.
The amount of substrate decreases as it is broken down, resulting in an increase in the amount of product.
As the reaction proceeds, there is less and less substrate and more and more product.
It becomes difficult for the substrate molecules to come into contact with the enzyme molecules, because there are fewer substrate molecules and also the product molecules may ‘get in the way’ of substrate molecules and prevent them from reaching an active site.
It therefore takes longer for the substrate molecules to be broken down by the enzyme and so its rate of disappearance slows.
Consequently, the rate of formation of product also slows.
Both graphs ‘tail off.’
The rate of reaction continues to slow until there is so little substrate that any further decrease in its concentration cannot be measured.
Why do the graphs flatten out?
The graphs flatten out, because:
- All the substrate has been used up
- So no new product can be produced