Enzymes Investigation

They are important because they break up, large, insoluble, molecules into smaller, soluble molecule, which then can go on and be used by the body.

This table shows some different types of enzymes and their job:

Enzyme

What it breaks down

Lipase

Fats into fatty acids

Protease

Protein into amino acids

Amalase

Starch

Carbohydrase

Carbohydrates into glucose

The enzyme I will be using in the practical is catalase. It is made by living cells and increases the rate of chemical reaction.

How temperature affects speed.

Not all collisions succeed in making products. The energy a collision needs to be successful is called activation energy. Increasing the temperature of a reaction means more particles have activation energy. This means more are successful, and it is more reactive.

In the practical I will also use hydrogen peroxide, which is a chemical that breaks down into water and oxygen.

Fair test- I will change one variable during the practical and to make it fair. This variable will be the temperature.

I also kept some variables the same:

* I will keep the concentration of the hydrogen peroxide at 10VOL.

* I will keep the amount (10ml) of hydrogen peroxide in each test tube the same.

* I will keep the weight of the potato the same (2 gram).

* I will keep the amount of drops, of detergent the same (2-3 drops).

Also to make the practical a fair test I will measure everything at eye level.

Safety- During the practical I will be using hydrogen peroxide, which could be potentially harmful. Hydrogen peroxide, if it comes into contact with the eye, cause blindness. It can also irritate the skin.

To make sure I will be reasonably safe during the experiment I will wear safety goggles to prevent the hydrogen peroxide getting into my eyes.

If the hydrogen comes into contact with my skin I will splash the affected area with water then inform my teacher what has happened.

When I carry out the practical I will also need to use a knife to cut the potato. To decrease the chance of cutting myself I will work in an area where there is a low chance of someone accidentally pushing into me while I work.

Conclusion-

---graph--

My results show that the enzyme catalase breaks down hydrogen peroxide fastest at 40°C.

The evidence I found proved to be correct. I found that the enzyme catalase broke down hydrogen peroxide best at 40°C. This is because the molecules get enough energy to move quickly (moving quickly produces more successful collisions) but it is not too high a temperature that the enzymes become denatured.

I conclude that catalase breaks down hydrogen peroxide into water and oxygen at 40°C. It works best at this temperature, as this is the enzymes optimum temperature. Catalase gets enough energy at 40°C to make the molecules move quickly. The quicker the molecules move the more chance there is of them making a successful collision. When a successful collision occurs the substrate fits into its enzyme like a key into a lock. When the substrate is in the enzyme, the enzyme breaks the substrate down.

Evaluation-

I found one anomalous result during the practical. I found this in my 0°C test where the height difference were much higher than I expected. They were higher because the fridge door was left open and the thermostat was at a higher temperature than 0°C. This higher temperature made the enzymes work better than they would at 0°C because the higher temperature resulted in more successful collisions.