BIOLOGY 123 LAB FINAL EXAM SCRIPT 2026
QUESTIONS WITH SOLUTIONS GRADED A+
● Enzymes are almost always ________ Answer:Proteins
● What is a catalyst? Answer:Speeds up a reaction without being
consumed or changed
● What is specificity? Answer:Has active site that binds to one
particular molecule (substrate) to catalyze specific reaction
● Do cells require enzymes? Why or why not? Answer:Yes, cells
require enzymes to allow reaction rates that support processes of life
● List the steps on how enzymes work. Answer:1. Substrate binding -
substrate binds to enzyme active site
2. Induced fit - substrate binding causes shape change in enzyme
forming E-S complex - substrate held more tightly
3. Product formation - Reaction occurs while substrates bound to
enzyme
4. Enzyme shape changes - Releasing products and returning active site
to original shape
,● Using what you know about catalysts, describe what happens after one
enzymatic reaction occurs and products are released. Answer:The
enzyme is "recycled" - NOT changed up or used
Ready to bind to more substrate
Will bind to substrate as soon as encountered as long as substrate is
available
● What is the maximum rate? Answer:Fastest rate at which enzymes
active sites are occupied
● How does an enzyme catalyze a reaction? Answer:By binding to a
substrate and lowering the activation energy, causing the reaction to
speed up
● How is the activation energy lowered in an enzymatic reaction?
Answer:Induced fit brings the reactant molecules closer together
This closeness puts more stress on the bonds and makes them easier to
break
● List the two different types of enzyme inhibitors and describe how
each inhibits enzymatic reaction. Answer:Competitive inhibitor - Binds
to active site of enzyme to prevent substrate bonding
Non-competitive inhibitor - Binds somewhere else and alters active site
to prevent substrate bonding
, ● pH 4 | pH 5 | pH 6 | pH 7 | pH 8 | pH 9 | pH 10
0 | + | ++ | +++ | +++ | ++ | 0
An enzyme was testing for reaction rate and the results recorded in the
same way as the data for the last lab.
What is the optimal pH for this enzyme and what happened at pH 10?
Answer:Optimal pH = pH 7 and pH 8
At pH 10, It denatured the enzyme causing it to break down tertiary and
secondary structures at the high pH levels
● What are the four factors that affect enzyme activity?
Answer:Temperature, pH, enzyme concentration, and substrate
concentration
● What happens at a low temperature vs. a high temperature on enzyme
activity? Answer:Low temperature - Not enough energy and the
products form slow
High temperature - Denatures active site and bonds begin to break
● What happens at a high pH vs. optimal pH? Answer:High pH -
Denatures enzyme and breaks down tertiary and secondary structures;
high salt concentrations break bonds
Optimal pH - pH that's most active - ions affect this
QUESTIONS WITH SOLUTIONS GRADED A+
● Enzymes are almost always ________ Answer:Proteins
● What is a catalyst? Answer:Speeds up a reaction without being
consumed or changed
● What is specificity? Answer:Has active site that binds to one
particular molecule (substrate) to catalyze specific reaction
● Do cells require enzymes? Why or why not? Answer:Yes, cells
require enzymes to allow reaction rates that support processes of life
● List the steps on how enzymes work. Answer:1. Substrate binding -
substrate binds to enzyme active site
2. Induced fit - substrate binding causes shape change in enzyme
forming E-S complex - substrate held more tightly
3. Product formation - Reaction occurs while substrates bound to
enzyme
4. Enzyme shape changes - Releasing products and returning active site
to original shape
,● Using what you know about catalysts, describe what happens after one
enzymatic reaction occurs and products are released. Answer:The
enzyme is "recycled" - NOT changed up or used
Ready to bind to more substrate
Will bind to substrate as soon as encountered as long as substrate is
available
● What is the maximum rate? Answer:Fastest rate at which enzymes
active sites are occupied
● How does an enzyme catalyze a reaction? Answer:By binding to a
substrate and lowering the activation energy, causing the reaction to
speed up
● How is the activation energy lowered in an enzymatic reaction?
Answer:Induced fit brings the reactant molecules closer together
This closeness puts more stress on the bonds and makes them easier to
break
● List the two different types of enzyme inhibitors and describe how
each inhibits enzymatic reaction. Answer:Competitive inhibitor - Binds
to active site of enzyme to prevent substrate bonding
Non-competitive inhibitor - Binds somewhere else and alters active site
to prevent substrate bonding
, ● pH 4 | pH 5 | pH 6 | pH 7 | pH 8 | pH 9 | pH 10
0 | + | ++ | +++ | +++ | ++ | 0
An enzyme was testing for reaction rate and the results recorded in the
same way as the data for the last lab.
What is the optimal pH for this enzyme and what happened at pH 10?
Answer:Optimal pH = pH 7 and pH 8
At pH 10, It denatured the enzyme causing it to break down tertiary and
secondary structures at the high pH levels
● What are the four factors that affect enzyme activity?
Answer:Temperature, pH, enzyme concentration, and substrate
concentration
● What happens at a low temperature vs. a high temperature on enzyme
activity? Answer:Low temperature - Not enough energy and the
products form slow
High temperature - Denatures active site and bonds begin to break
● What happens at a high pH vs. optimal pH? Answer:High pH -
Denatures enzyme and breaks down tertiary and secondary structures;
high salt concentrations break bonds
Optimal pH - pH that's most active - ions affect this
