What do enzymes catalyse in an enzyme-controlled reaction?
Substrates turning into products.
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What can an investigation into enzyme activity follow to measure the rate of reaction?
The rate that the substrate is used up or the rate that the product is formed.
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How many variables do investigations into enzyme activity measure?
One.
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What is the independent variable?
The variable set by the investigator.
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What is the dependent variable?
The variable that is measured.
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Why does the independent variable have to be set precisely?
Because otherwise the dependent variable is meaningless.
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What is the minimum range of independent variables you should investigate?
Five values.
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What should you do with the enzyme and substrate before the investigations begins, how is this achieved, and why do we do this?
Get them to the same temperature by placing both separately in a water bath at the required temperature until they reach it because adding cold enzyme and substrate together before placing them in a water bath wouldn't give a precise temperature.
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What variables need to be controlled in a enzyme-controlled reaction?
All the variables that are not being investigated; they need to be kept constant.
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What are the 4 key variables?
Temperature, enzyme concentration, substrate concentration, and pH.
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What are the 2 main ways of measuring the reaction rate?
Start the reaction and then measure the concentration of product after a fixed period of time, or monitor the reaction by taking readings of product formation at a number of intervals.
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Why must a suitable time scale be used when doing enzyme-controlled reactions?
Because the reactions are often rapid.
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What will enzyme-controlled reaction time scales be measured in?
Seconds or minutes.
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What is the calculation for rate of reaction?
1÷time
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What is on each axis on a reaction rate graph?
x-axis will have the independent variable and the y-axis will have the rate of reaction.
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What kind of test is often included in enzyme-controlled investigations and what does it show?
A control test, which shows it is the enzyme action that affects the reaction.
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Define variable.
Any factor that may change and affect the reaction rate. Investigations require all variables to be controlled.
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What terms should you use when explaining why the reaction rate is changing?
How the factors affect collisions and the forming of enzyme-substrate complexes, or how the factor affects the shape of the active sites.
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Other cards in this set
Card 2
Front
What do enzymes catalyse in an enzyme-controlled reaction?
Back
Substrates turning into products.
Card 3
Front
What can an investigation into enzyme activity follow to measure the rate of reaction?
Back
Card 4
Front
How many variables do investigations into enzyme activity measure?
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