AP Bio Unit 3 - Enzymes and Cellular
Respiration Exam Questions and
Answers
Enzymes - Correct Answers -Macromolecules and biological catalysts that speed up
biochemical reactions.
- Most enzymes are PROTEINS and usually end in -ASE
- TERTIARY SHAPE must be maintained for functionality
- Have a region called an ACTIVE SITE
Substrate - Correct Answers -The REACTANT that binds to the ACTIVE SITE
Active Site - Correct Answers -A region on an enzyme that binds to a protein or other
substance during a reaction.
Activation Energy - Correct Answers -Initial starting energy, energy used to start all
biochemical reactions
How do enzymes affect activation energy, and how does this affect the rate of reaction?
- Correct Answers -Enzymes lower the activation energy requirement of all enzyme-
mediated reactions, which accelerates the rate of reactions.
Denaturation - Correct Answers -Changes in the conformational shape of the enzyme.
Some environmental factors that could lead to enzyme denaturation are changes in
temperature and changes in environmental pH. It results in catalytic ability of the
enzyme to be lost or severely decreased. In some cases, denaturation in enzymes is
reversible, allowing the enzyme to regain catalytic abilities
Why does an initial slight increase in temperature increase the rate of enzyme catalyzed
reactions, but a larger more extreme and pronounced change in temperature decreases
the rate of reaction? - Correct Answers -At LOW temperatures, an increase in
temperature INCREASES the rate of an enzyme-catalyzed reaction.
What does the function of an enzyme depend on? - Correct Answers -1.) Its Three-
Dimensional Shape
2.) Temperature
3.) Ionic Conditions
4.) pH of its surroundings
Which group of biomolecules do enzymes belong to? - Correct Answers -Proteins
, Can enzymes be reused? - Correct Answers -Yes
Why do enzymes facilitate only one type of reaction? - Correct Answers -Enzyme
structure is very specific, resulting in each enzyme only facilitating one type of reaction.
They can facilitate SYNTHESIS or DIGESTION REACTIONS.
At HIGHER temperatures, the protein is DENATURED, and the rate of the reaction
dramatically DECREASES. An enzyme has an optimum pH range in which it exhibits
maximum activity.
How is the effect of raising the temperature above the optimum for a given enzyme
different from the effect of lowering the temperature below the optimum for a given
enzyme? - Correct Answers -While raising the temperature generally speeds up a
reaction, and lowering temperature slows down a reaction, extreme high temperatures
can cause an enzyme to lose its shape (denature) and stop working.
Why do changes in pH affect reaction rate? - Correct Answers -pH measures the
concentration of hydrogen ions in solution and is measured on a logarithmic scale.
Small changes in pH values equate to large shifts in hydrogen ion concentration.
- Ex: pH 6 has 10x more hydrogen ions in its solution than pH 7
Explain how increasing substrate concentration affects the reaction rate. - Correct
Answers -Increasing substrate concentration also increases the rate of reaction to a
certain point. Once all of the enzymes have bound, any substrate increase will have no
effect on the rate of reaction, as the available enzymes will be saturated and working at
their maximum rate.
Explain how increasing enzyme concentration affects the reaction rate. - Correct
Answers -Increasing enzyme concentration will speed up the reaction, as long as there
is substrate available to bind to.
LESS enzymes = SLOWER reaction rates because there will be less opportunities for
substrates to collide with active sites
MORE enzymes = FASTER reaction rate because there will be more opportunities for
substrates to collide with active sites
Competitive Inhibitors - Correct Answers -- They can bind to the active site
- Molecules can bind reversibly or irreversibly to the active site of the enzyme
- Competes with the normal substrate for the enzymes' active site
If inhibitor concentrations exceed substrate concentrations reactions are slowed. If
inhibitor concentration are considerably lower than substrate concentrations, reactions
can proceed normally
Respiration Exam Questions and
Answers
Enzymes - Correct Answers -Macromolecules and biological catalysts that speed up
biochemical reactions.
- Most enzymes are PROTEINS and usually end in -ASE
- TERTIARY SHAPE must be maintained for functionality
- Have a region called an ACTIVE SITE
Substrate - Correct Answers -The REACTANT that binds to the ACTIVE SITE
Active Site - Correct Answers -A region on an enzyme that binds to a protein or other
substance during a reaction.
Activation Energy - Correct Answers -Initial starting energy, energy used to start all
biochemical reactions
How do enzymes affect activation energy, and how does this affect the rate of reaction?
- Correct Answers -Enzymes lower the activation energy requirement of all enzyme-
mediated reactions, which accelerates the rate of reactions.
Denaturation - Correct Answers -Changes in the conformational shape of the enzyme.
Some environmental factors that could lead to enzyme denaturation are changes in
temperature and changes in environmental pH. It results in catalytic ability of the
enzyme to be lost or severely decreased. In some cases, denaturation in enzymes is
reversible, allowing the enzyme to regain catalytic abilities
Why does an initial slight increase in temperature increase the rate of enzyme catalyzed
reactions, but a larger more extreme and pronounced change in temperature decreases
the rate of reaction? - Correct Answers -At LOW temperatures, an increase in
temperature INCREASES the rate of an enzyme-catalyzed reaction.
What does the function of an enzyme depend on? - Correct Answers -1.) Its Three-
Dimensional Shape
2.) Temperature
3.) Ionic Conditions
4.) pH of its surroundings
Which group of biomolecules do enzymes belong to? - Correct Answers -Proteins
, Can enzymes be reused? - Correct Answers -Yes
Why do enzymes facilitate only one type of reaction? - Correct Answers -Enzyme
structure is very specific, resulting in each enzyme only facilitating one type of reaction.
They can facilitate SYNTHESIS or DIGESTION REACTIONS.
At HIGHER temperatures, the protein is DENATURED, and the rate of the reaction
dramatically DECREASES. An enzyme has an optimum pH range in which it exhibits
maximum activity.
How is the effect of raising the temperature above the optimum for a given enzyme
different from the effect of lowering the temperature below the optimum for a given
enzyme? - Correct Answers -While raising the temperature generally speeds up a
reaction, and lowering temperature slows down a reaction, extreme high temperatures
can cause an enzyme to lose its shape (denature) and stop working.
Why do changes in pH affect reaction rate? - Correct Answers -pH measures the
concentration of hydrogen ions in solution and is measured on a logarithmic scale.
Small changes in pH values equate to large shifts in hydrogen ion concentration.
- Ex: pH 6 has 10x more hydrogen ions in its solution than pH 7
Explain how increasing substrate concentration affects the reaction rate. - Correct
Answers -Increasing substrate concentration also increases the rate of reaction to a
certain point. Once all of the enzymes have bound, any substrate increase will have no
effect on the rate of reaction, as the available enzymes will be saturated and working at
their maximum rate.
Explain how increasing enzyme concentration affects the reaction rate. - Correct
Answers -Increasing enzyme concentration will speed up the reaction, as long as there
is substrate available to bind to.
LESS enzymes = SLOWER reaction rates because there will be less opportunities for
substrates to collide with active sites
MORE enzymes = FASTER reaction rate because there will be more opportunities for
substrates to collide with active sites
Competitive Inhibitors - Correct Answers -- They can bind to the active site
- Molecules can bind reversibly or irreversibly to the active site of the enzyme
- Competes with the normal substrate for the enzymes' active site
If inhibitor concentrations exceed substrate concentrations reactions are slowed. If
inhibitor concentration are considerably lower than substrate concentrations, reactions
can proceed normally
