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Year 10
AQA
Foundation

The effect of temperature on the rate of decomposition by an enzyme: data analysis and evaluation

I can analyse, explain and evaluate the results of an experiment investigating how temperature affects the rate of decomposition of milk by an enzyme.

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New
New
Year 10
AQA
Foundation

The effect of temperature on the rate of decomposition by an enzyme: data analysis and evaluation

I can analyse, explain and evaluate the results of an experiment investigating how temperature affects the rate of decomposition of milk by an enzyme.

Download all resources
Share activities with pupils

Lesson details

Key learning points

  1. Calculate rate of reaction where rate = 1/time taken to reach the end point.
  2. Plot a graph of results (x-axis = temperature and y-axis = rate, or time taken to reach end point).
  3. Interpret the results and evaluate how well they support the hypothesis.
  4. Explain the results using ideas about the effect of temperature on the rate of enzyme activity.

Common misconception

As pH increases above the optimum, enzymes denature and reaction rate falls; but this is not what happens at pHs below the optimum, so the graph and explanation resemble temperature.

The process of denaturing an enzyme is explored in detail, and a graph of reaction rate is explained carefully to make it clear that the changes to rate occur above and below the optimum pH.

Keywords

  • Rate - The rate is how quickly something takes place. The rate of a reaction is a measure of how much change occurs per unit of time.

  • End point - The point at which a reaction is complete, often indicated by a change in colour of an indicator.

  • Hypothesis - A precise, measurable and testable statement based on observations about how something works.

  • Active site - The part of an enzyme where the substrate binds.

  • Denature - A permanent change in the shape of an enzyme which stops it from working.

Ask students to use their own data, but pre-prepared data is provided if theirs is of low quality. A sample set of data and a graph axes is provided to support pupils.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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Starter quiz

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6 Questions

Q1.
In most reactions, what will an increase in temperature result in?
Correct answer: An increase in the rate of a reaction
A decrease in the rate of a reaction
No change to the rate of a reaction
Q2.
What type of microscopic organisms carry out decomposition?
animals
plants and fungi
humans and plants
Correct answer: bacteria and fungi
Q3.
In enzyme catalysed reactions, how will an increase in temperature affect the rate of the reaction?
The reaction will increase as the temperature increases
Correct answer: The reaction increases until the enzyme starts to denature - the reaction slows
The enzyme works at the same rate whatever the temperature
The rate slows down as the temperature increases
Q4.
What is meant by the 'optimum' temperature in an enzyme catalysed reaction?
Correct answer: When the enzyme is working fastest
When the enzyme is becoming denatured
When there are small numbers of collisions between the enzyme and substrate
When there is no substrate left for the enzyme to break down
Q5.
Why are moisture levels important in the rate of decomposition?
Decomposers need water to carry out respiration
Decomposers need water in order to photosynthesise
Decomposers are aquatic organisms - they live in water
Correct answer: Decomposers secrete enzymes to break down organic matter and this requires water
Q6.
What happens to manure (animal waste) that is put onto a field by a farmer?
Manure is broken down by the plants that grow in the soil.
The manure gets washed into the soil by rainfall.
Correct answer: The manure is broken down by decomposers.
Nothing - it just helps to replace soil which may have been eroded.

Exit quiz

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6 Questions

Q1.
In an experiment to determine the effect of temperature on the rate of decomposition by an enzyme, it takes 5 seconds for the indicator to reach the end point. What is the rate of the reaction?
5
1
0.5
Correct answer: 0.2
0.02
Q2.
A range of equipment and chemicals are used in the experiment to determine the effect of temperature on the rate of decomposition by an enzyme. Match the words with their function in the experiment.
Correct Answer:lipase,enzyme (works on lipids)

enzyme (works on lipids)

Correct Answer:Cresol red,indicator (used to measure the end point)

indicator (used to measure the end point)

Correct Answer:lipids,found in milk (the substrate)

found in milk (the substrate)

Correct Answer:fatty acids,the product (decreases pH of the solution)

the product (decreases pH of the solution)

Q3.
At which of the following points are enzymes being denatured?
An image in a quiz
a
b
Correct answer: c
Q4.
Point b in the graph is known as the enzyme's optimum temperature. Which of the following statements explains what is happening at point 'b'?
An image in a quiz
The active sites of the enzymes are changing as it becomes denatured.
Correct answer: The number of collisions between enzymes & substrate are most frequent.
There are fewer collisions taking place between the enzyme and substrate.
Q5.
What is the name of the part of the enzyme that the substrate needs to collide with for a reaction to take place?
Correct Answer: active site
Q6.
How does keeping food such as meat or fish in the fridge help to slow the rate of decomposition?
The fridge door prevents oxygen from getting into the fridge.
Correct answer: The low temperature of the fridge slows enzyme activity.
The fridge helps to dry the food.
The low temperature increases the number of bacteria

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