1. Lesson Starter
What is the name of the muscular tube which connects the mouth and stomach?
Describe the process of peristalsis
Describe the role of churning in the stomach

2. Learning Intention To be able to explain where pepsin is produced
To be able to describe the role of pepsin
To investigate the effect of pH on pepsin

3. Optimum conditions for enzymes
The more ACTIVE an enzyme is, the faster the REACTION RATE
Enzyme at its most active- OPTIMUM CONDITIONS
Temperature pH
Out with optimum- not enough/ dentaure

4. Optimum temperature Enzymes are everywhere (not just inside us)
Body enzymes- 37°C
Before 37°C- not enough energy, few collisions, UNDAMAGED
35-40ish°C- WORKING RANGE- enzyme works, OPTIMUM=37°C
>40°C- DENATURED, lost shape, lock and key

5. What is pH?

6. Optimum pH Different enzymes have a different working range Acid
Neutral
Alkaline

7. Pepsin Digestive enzyme Produced in the stomach
Speeds up breakdown of protein
Peptides

8. Pepsin experiment- overview
Observe the change in disks of egg white (protein) when pepsin is added at 3 different pHs.

9. Pepsin experiment (copy and complete)
AIM
To find out the OPTIMUM pH for the enzyme PEPSIN
Hypothesis
What do you expect to happen in this experiment?
I think that pepsin will work best in _______ conditions

10. Experiment Instructions *WEAR YOUR GOGGLES* Apparatus 3 x test tubes
Test tube rack
Bottle of pepsin
Bottle of acid
Bottle of alkali
Bottle of neutral
3 x egg white disks
labels
Instructions
*WEAR YOUR GOGGLES*
Collect apparatus
Label your 3 test tubes- (acid, alkali, neutral)
Place a disk of egg white in each test tube
Cover each disk with PEPSIN
Add 5mls of acid to the test tube labelled acid (alkali to alkali, neutral to neutral)
Place in water bath at 40°C
Leave for mins (clear up chemicals)
Examine the appearance of egg white

11. Method
Apparatus list- write down a list of all the chemicals and equipment that you used
Step by step instructions- write down instructions that someone else could follow to do this exact experiment
Diagram- Draw a LABELLED diagram using a RULER to show how the set up is arranged

12. Results
Describe the appearance of your egg white in each of the test tubes (stating which pH they have been in at)
Conclusion
What is the optimum pH for pepsin?
How do you know?
Did your hypothesis agree with the results?
Explain why it is important that pepsin works best at this pH, considering where it is found in the body.