Uploaded by Nashita HOSSAIN

L8 Enzymes and temperature

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Date: Saturday, 02 December 2023
Enzymes and temperature
Learning intention: Understand how enzymes help speed up
chemical reactions in the human body
Success criteria
• Explain why enzymes are specific
• Investigate how temperature
affects enzyme action
• Justify why enzymes are
denatured by high temperatures
and extremes of pH
Do Now Tasks
Name a type of food test and the
reagent used
Explain why it is important that we
know what is in our food
Suggest how temperature could
affect enzymes in the body
Explain why enzymes are
specific
“
Justify why enzymes are
denatured by high temperatures
and extremes of pH
Isabella is turning 1!
It is important our bodies maintain an optimum
temperature. What might happen if we don’t ?
“
ENGAGE
Investigate how temperature
affects enzyme action
Explain why enzymes are
specific
EXPLORE
Investigate how temperature
affects enzyme action
Justify why enzymes are
denatured by high temperatures
and extremes of pH
The need for enzymes
Each of your cells can have a hundred or more chemical reactions
going on inside it at any one time.
Each one of these different types of reaction is controlled by a
different enzyme.
Enzymes do not change reactions in any way. They just make
reactions happen faster.
They do this by lowering the ‘activation energy’ for the reaction.
Explain why enzymes are
specific
EXPLORE
Investigate how temperature
affects enzyme action
Justify why enzymes are
denatured by high temperatures
and extremes of pH
The need for enzymes
Enzymes are denatured by temperature and pH
Explain why enzymes are
specific
EXPLORE
Investigate how temperature
affects enzyme action
Justify why enzymes are
denatured by high temperatures
and extremes of pH
The need for enzymes
Biological reactions are affected by the same factors as any other
chemical reactions:
•
Concentration
•
Surface Area
•
Temperature
However, in a living organism an increase in temperature will only
increase a reaction up to a certain point.
Explain why enzymes are
specific
EXPLORE
Investigate how temperature
affects enzyme action
Justify why enzymes are
denatured by high temperatures
and extremes of pH
Enzymes and temperature
Task: Watch the video on the next slide demonstrating an
investigation into the affect of temperature on enzymes.
Write a full method for the experiment. Self-assess using PURPLE pen.
Record the results of the experiment.
Write a conclusion based on the results.
Challenge: Justify the science behind your conclusion.
Extra challenge: Evaluate the investigation. Include
suggestions for improvements and justify your suggestions.
Explain why enzymes are
specific
Investigate how temperature
affects enzyme action
Justify why enzymes are
denatured by high temperatures
and extremes of pH
Explain why enzymes are
specific
EXPLAIN
Investigate how temperature
affects enzyme action
Justify why enzymes are
denatured by high temperatures
and extremes of pH
The need for enzymes
The affects of temperature – Practical
Set up water baths at various temperatures (e.g. 0°C, 20°C, 40°C, 60°C
and 80°C).
Add starch solution to 5 test tubes.
Add amylase solution to another 5 test tubes.
Place one starch and one amylase test tube into each water bath for 5
minutes - to allow the enzyme and substrate to reach the desired
temperature.
Place 1 drop of iodine into each dimple on a spotting tile.
Add the amylase to the starch in the 0°C water bath.
Explain why enzymes are
specific
EXPLAIN
Investigate how temperature
affects enzyme action
Justify why enzymes are
denatured by high temperatures
and extremes of pH
The need for enzymes
The affects of temperature – Practical
Start the timer.
Every minute remove a sample of the starch-amylase solution and add it to
a drop of iodine on the spotting tile.
Repeat step 8 until the iodine no longer changes colour - meaning that
there is no starch present, in other words the amylase has broken all starch
down.
Repeat steps 6-9 for each of the temperatures. Record results.
Draw a graph to show the time taken for starch to be digested at different
temperatures.
Explain why enzymes are
specific
Investigate how temperature
affects enzyme action
Justify why enzymes are
denatured by high temperatures
and extremes of pH
Task: Describe each graph then explain the effects Identify at which pH
pepsin works best.
of different temperature and pH on enzymes.
Effect of pH on enzyme activity
0 10 20 30 40 50
Temperature (⁰C)
60
Relative activity
Rate of reaction
Relative activity
Effect of temperature on an
enzyme
Explain what happens to
the enzyme activity as the
pH increases.
pepsin
0
2
4
6
pancreatic amylase
4
6
Identify at which pH
pancreatic amylase works
best.
8
10
Challenge: Justify why this
change happens.
Support: In your description
include these key words:
• Optimum
• Rate
• Denatured
Explain why enzymes are
specific
Investigate how temperature
affects enzyme action
Justify why enzymes are
denatured by high temperatures
and extremes of pH
Feedback to feedforward: Swap your work with
someone else on your table. Check their answers are
correct. Check their work and identify WWW and EBI.
You have 4 minutes.
What went well: Identify good knowledge and understanding.
Even better if: Identify and suggest areas for improvement.
Challenge: Suggest what other factors could affect the
function of enzymes
Explain why enzymes are
specific
Investigate how temperature
affects enzyme action
Justify why enzymes are
denatured by high temperatures
and extremes of pH
Feedback to feedforward: Use your feedback to
make improvements to your work, using PURPLE
pen.
Challenge: Suggest what other factors could affect the
function of enzymes
Explain why enzymes are
specific
EXTEND
Investigate how temperature
affects enzyme action
Justify why enzymes are
denatured by high temperatures
and extremes of pH
The need for enzymes
Different enzyme’s have a different optimum pH.
Suggest what type of conditions you think the enzymes in the
stomach prefer.
Explain why enzymes are
specific
Investigate how temperature
affects enzyme action
Justify why enzymes are
denatured by high temperatures
and extremes of pH
Task: Draw a single diagram (no words) to
demonstrate something you have learnt today.
Challenge: Create a question that you can answer,
but make it as difficult as you can for others in the
class.
Post it in the chat on Teams for others to answer.
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