Enzyme Basics
These biological molecules speed up chemical reactions without being consumed.
Enzymes
Raising this too high causes an enzyme to lose its shape and stop working.
Heat/temperature
On an enzyme activity graph, this axis usually shows temperature, pH, or concentration.
x-axis
This is the one thing you change on purpose in an enzyme lab (e.g., temperature).
independent variable
The specific region of an enzyme where the substrate binds.
Substrate
This term describes when an enzyme’s shape is permanently changed and it no longer functions.
denaturation
If a graph shows enzyme activity dropping sharply after 40°C, this is likely happening to the enzyme.
denaturing
This is what you measure—like how much product is made or how fast bubbles form.
dependent variable
Enzymes are typically made of this type of macromolecule.
Proteins
Most human enzymes work best around this pH (a neutral value).
7
How can you tell from a graph that denaturation has occurred?
activity decreases after a peak (instead of leveling off)?
These are kept the same in all trials (like volume of solution or type of enzyme).
controlled variables
The substance an enzyme works on (like Lactose for Lactase).
Substrate
Why does enzyme activity drop at very low or very high pH?
denaturation
What happens when the temperature is too low for an enzyme
inactive enzyme
In an experiment testing how pH affects catalase, name one controlled variable.
temperature
True or false: Enzymes are not used up in reactions—this means they can be used again and again.
True
On a graph of enzyme activity vs. temperature, the peak shows this.
optimum
True or false: an inactive enzyme cannot work again
false
Why is it important to only change one variable at a time in an enzyme experiment?
so you know which change caused the effect (to make it a fair test)