AP BIO ENZYME QUIZ STUDY GUIDE
Q&A
What is feedback inhibition? How does this work? Why would we not want an
enzyme working in a pathway non-stop (unregulated)? Be familiar with the isoleucine
pathway example from your text (page 132 figure 6.19) - ANSWER-A mode of
metabolic control. A metabolic pathway is switched off by the inhibitory binding of its
end product to an enzyme that acts early in the pathway. If we left it unregulated, the
cell would waste chemical resources and get an overflow of unnecessary materials.
-What is an enzyme? - ANSWER-A macromolecule that acts as a catalyst, a
chemical agent that speeds up a reaction without being consumed by it.
-How do enzymes speed up the rate of a reaction? - ANSWER-It lowers the
activation energy required to reach the transition state.
Specific ways: Activation site is a template for the substrates to meet in a proper
orientation. Enzyme enfolds the substrates and brings them towards transition state
form. Active site can provide a microenvironment that is more conducive to a
particular reaction than the solution on its own. Active site can directly participate as
well, such as by covalently bonding to the substrate.
-Why is shape so important for enzymes? What happens when an enzyme becomes
denatured? - ANSWER-The shape of an enzyme (more specifically, its active site)
determines which substrate it can bind to. The induced fit that forms enhances this fit
between the site and substrate. When denatured, its shape changes and it will no
longer function since it cannot fit a substrate.
What is activation energy? - ANSWER-The "free energy of activation"
The initial investment of energy in a reaction, needed to contort the reactant
molecules enough to break the bonds (to set it in transitional form, in which the
bonds can break). Represented by E subA.
-What is a substrate? - ANSWER-The reactant an enzyme acts on/binds to
-What is an active site? - ANSWER-The region of an enzyme which binds to the
substrate; where the catalysis actually occurs. Formed by only a few on the enzymes
amino acids, while the rest make a framework determining the configuration of the
site.
- What is the enzyme substrate complex? - ANSWER-The enzyme bound to the
substrate(s); while they are joined, the catalysis occurs and the product(s) are made
-How many different types of enzymes can act on one type of substrate? Why? -
ANSWER-Only one type of substrate, due to the very specific shapes of both the
substrates and the enzymes.
Q&A
What is feedback inhibition? How does this work? Why would we not want an
enzyme working in a pathway non-stop (unregulated)? Be familiar with the isoleucine
pathway example from your text (page 132 figure 6.19) - ANSWER-A mode of
metabolic control. A metabolic pathway is switched off by the inhibitory binding of its
end product to an enzyme that acts early in the pathway. If we left it unregulated, the
cell would waste chemical resources and get an overflow of unnecessary materials.
-What is an enzyme? - ANSWER-A macromolecule that acts as a catalyst, a
chemical agent that speeds up a reaction without being consumed by it.
-How do enzymes speed up the rate of a reaction? - ANSWER-It lowers the
activation energy required to reach the transition state.
Specific ways: Activation site is a template for the substrates to meet in a proper
orientation. Enzyme enfolds the substrates and brings them towards transition state
form. Active site can provide a microenvironment that is more conducive to a
particular reaction than the solution on its own. Active site can directly participate as
well, such as by covalently bonding to the substrate.
-Why is shape so important for enzymes? What happens when an enzyme becomes
denatured? - ANSWER-The shape of an enzyme (more specifically, its active site)
determines which substrate it can bind to. The induced fit that forms enhances this fit
between the site and substrate. When denatured, its shape changes and it will no
longer function since it cannot fit a substrate.
What is activation energy? - ANSWER-The "free energy of activation"
The initial investment of energy in a reaction, needed to contort the reactant
molecules enough to break the bonds (to set it in transitional form, in which the
bonds can break). Represented by E subA.
-What is a substrate? - ANSWER-The reactant an enzyme acts on/binds to
-What is an active site? - ANSWER-The region of an enzyme which binds to the
substrate; where the catalysis actually occurs. Formed by only a few on the enzymes
amino acids, while the rest make a framework determining the configuration of the
site.
- What is the enzyme substrate complex? - ANSWER-The enzyme bound to the
substrate(s); while they are joined, the catalysis occurs and the product(s) are made
-How many different types of enzymes can act on one type of substrate? Why? -
ANSWER-Only one type of substrate, due to the very specific shapes of both the
substrates and the enzymes.
