BIOLOGY 123 EXAM 2 QUESTIONS AND
100% VERIFIED CORRECT ANSWERS!!!
Proteins consist of __________ bonds
Polypeptide
Enzymes are almost always ________
Proteins
What is a catalyst?
Speeds up a reaction without being consumed or changed
What is specificity?
Has active site that binds to one particular molecule (substrate) to catalyze specific reaction
Do cells require enzymes? Why or why not?
Yes, cells require enzymes to allow reaction rates that support processes of life
List the steps on how enzymes work.
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.
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?
, Fastest rate at which enzymes active sites are occupied
How does an enzyme catalyze a reaction?
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?
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.
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?
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?
Temperature, pH, enzyme concentration, and substrate concentration
What happens at a low temperature vs. a high temperature on enzyme activity?
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?
100% VERIFIED CORRECT ANSWERS!!!
Proteins consist of __________ bonds
Polypeptide
Enzymes are almost always ________
Proteins
What is a catalyst?
Speeds up a reaction without being consumed or changed
What is specificity?
Has active site that binds to one particular molecule (substrate) to catalyze specific reaction
Do cells require enzymes? Why or why not?
Yes, cells require enzymes to allow reaction rates that support processes of life
List the steps on how enzymes work.
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.
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?
, Fastest rate at which enzymes active sites are occupied
How does an enzyme catalyze a reaction?
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?
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.
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?
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?
Temperature, pH, enzyme concentration, and substrate concentration
What happens at a low temperature vs. a high temperature on enzyme activity?
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?
