Enzymes Flashcards
Enzyme is
A type of protein that is A biological catalyst that speeds up the rate of reaction but is not used up.
Enzymes are specific
Only attach onto one type of substante
Enzymes can
Break down a large substate into smaller molecules. Or help smaller chemicals join.
Starch +
Amylase= glucose
Starch = polymer
Amylase = enzymes
Glucose= monomers
Glycogen +
Glucase = glucose
Glycogen = polymer
Glucase= Enzymes
Glucose = monomers
Protein +
Protease = amino acids
Protein= polymer
Protease = enzymes
Amino acids = monomers
Lipids +
Lipase = glycerol and fatty acids
Lipids= Polymer
Lipase= Enzymes
Glycerol and fatty acids= Monomers
Substate
A molecule that is changed in a reaction. Will fit into an active site of the enzyme. Must be complimentary.
Active site
The part the substrate joins to the enzymes
Lock and key model
Substrate fits into the enzymes just like a key fits into a lock and make it I into products.
Metabolic reactions
Useful chemical reactions in the body.
Temperature on enzymes: high
Higher temperature increases the kinetic energy of the particles and enzymes so there is a greater number of collisions and a higher reaction rate. Temperature too high and enzymes denature.
Denaturing
Changes the shape of the active site because the bonds holding the enzyme together break and can no longer react so it stops. It is irreversible, can not function.
Temperature of enzymes: cold
Less kinetic energy for movement of particles and enzymes, less collisions and slow reaction rate. Do not denature at low temperatures so will function again.
Optimum temperature
Is the temperature at which the collisions rate is the greatest, work best at this temperature
Practical : how temperature affects enzymes activity
Watch a video
1)
The enzyme catalase catalyses the breakdown
of hydrogen peroxide into water and oxugen.
2) You can collect the oxygen and measure
how much is produced in a set time.
3) Use a pipette to add a set
hydrogen peroxide to a boilins tube.
Put the tube in a water bath at 10 °C.
4) Set up the rest of the apparatus as shown.
Add a source of catalase (e.g. 1 cm}
of potato) to the hydrogen peroxide
and quickly attach the bung.
5) Record how much oxygen is produced in the first minute. Repeat three times and calculate the mean.
6) Repeat at 20 °C, 30 °C and 40 °C.
7) Control any variables (e.g. pH, the potato used, the size of potato pieces, etc.) to make it a fair test.
Enzymes ph
Enzymes work at an optimum ph. Too high or two low the active site will denature.
Practical: investigate how enzymes activity can affect changes in ph
Watch a video
1)You can adapt these experiments to investigate the effect of pH on enzyme activity.
2)
Follow the same method, but add a buffer solution with a different pH level to a series of
different tubes containing the enzyme-substrate mixture.
3) As before, control any variables
- use the water bath to keep the temperature of the reaction
mixture the same for each pH, and make sure volumes and concentrations are kept the same.
