Enzymes Flashcards
What are enzymes
They are biological catalysts that speed up chemical reactions without being changed
What is a catalyst
A chemical that increases the rate of reaction but remains unchanged at the end of the reaction
What is an active site
The area of an enzyme where a substrate will bind
What is a substrate
A molecule upon which an enzyme will act
What is lock and key model
The model used to describe the binding of specific substances to specify enzymes
What is monosaccharide
A single sugar molecule
What is disaccharide
2 single sugar molecule bonded together
What is polysaccharide
Multiple sugar molecules bonded together
What is a anabolic reaction
Building larger molecules from smaller molecular
What is a catabolic reaction
Breaking down larger molecules into smaller molecules
How will a higher temperature increase the rate of reaction and cause denaturation
The enzymes will gain kinetic energy and so there will be more frequent collision between the enzyme and substrate which will increase the rate of reaction. This will happen until the optimal temperature. After that point the bonds holding the enzyme will start to break. This will cause the active site to lose its shape, thus the enzyme becomes denatured and doesn’t bind with the substrate anymore.
Describe how an enzyme can break down a substrate
The reaction would be called a catabolic reaction. The enzyme will bind with the enzyme at the active site. It will break the bonds of the substrate turning it into smaller soluble bits.
What is activation energy
Its the amount of energy needed to start a chemical reaction.
What is the aim of the practical of enzymes and temperature
To investigate how enzymes activity can be affected by changes in temperature
Equipment list
Pieces of fresh and boiled liver Scalpel
Weighing scales
Hydrogen peroxide
Distilled water Test tubes Ruler
Stop watch
Risk assessment
Goggles - Hydrogen peroxide is an irritant and corrosive. It could damage the eyes.
Method
- Take one piece of fresh liver and one piece of boiled liver.
- Cut them to make sure they are the same size/mass (this may have been done for you).
- Place each piece in a separate test tube.
- Add the 5ml of hydrogen peroxide to each test tube and start the stopwatch.
- After 5 minutes record the height of the froth produced.
- Repeat the experiment.
What happens in this practical
Catalase is an enzyme found in living tissue. Its role is to break down the toxic waste product Hydrogen peroxide into oxygen and water.(froth)
Conclusion
As the temperature increases he enzyme activity increases until an optimal temperature. This is shown in the results as the fresh liver has a mean foam height of 15.73cm and the boiled liver has a mean foam height of 8.87cm
How does an enzyme become denatured
The binds holding the enzyme together break causing the active site to change shape, therefore the substrate will no longer fit into the active site causing the enzyme to become denatured
What is the aim of the practical of enzymes and pH
Investigate how enzyme activity can be affectedby changes in pH
Equipment list
•test tubes
•a test tube rack of buffered solutions covering a range of pH
•water bath
•spotting tiles
•5cm3 measuring cylinder
•pipettes
•a stop clock
•starch solution
•amylase solution
•iodine solution
Method
1.Place one drop of iodine solution into each depression on the spotting tile.
2.In a clean test tube, add 2 ml of starch to 2ml of buffered pH solution.
3.Add 2ml amylase to the starch and buffered pH solution and begin timing immediately.
4.Every 30 seconds remove a drop of the mixture and put this into one of the iodine depressions. Watch for a colour change.
5.Continue until the mixture remains orange when added to the buffer solution.
6.Record your results
Method
1.Place one drop of iodine solution into each depression on the spotting tile.
2.In a clean test tube, add 2 ml of starch to 2ml of buffered pH solution.
3.Add 2ml amylase to the starch and buffered pH solution and begin timing immediately.
4.Every 30 seconds remove a drop of the mixture and put this into one of the iodine depressions. Watch for a colour change.
5.Continue until the mixture remains orange when added to the buffer solution.
6.Record your results