AP Bio: Module 8

Which of these is exhibiting kinetic energy?

the high-energy phosphate bonds of a molecule of ATP
a space station orbiting Earth
a rock on a mountain ledge
a person sitting on a couch while watching TV
an archer with a flexed bow

"Conservation of energy" refers to the fact that _____.

the net amount of disorder is always increasing
no chemical reaction is 100 percent efficient
energy cannot be created or destroyed but can be converted from one form to another
if you conserve energy you will not be as tired

Chemical energy is a form of _____ energy.

motion
heat
kinetic
potential
entropic

In your body, what process converts the chemical energy found in glucose into the chemical energy found in ATP?

redox
digestion
anabolism
potentiation
cellular respiration

Which of these are by-products of cellular respiration?

heat, carbon dioxide, and water
glucose, carbon dioxide, and water
ATP, carbon dioxide, and water
carbon dioxide and water
ATP and carbon dioxide

Which of the following is true of metabolism in its entirety in all organisms?

Metabolism depends on a constant supply of energy from food.
Metabolism consists of all the energy transformation reactions in an organism.
Metabolism uses all of an organism's resources.

Anabolic pathways _____.

are usually highly spontaneous chemical reactions
release energy as they degrade polymers to monomers
consume energy to build up polymers from monomers
consume energy to decrease the entropy of the organism and its environment

Which term most precisely describes the cellular process of breaking down large molecules into smaller ones?

dehydration
metabolism
anabolism (anabolic pathways)
catabolism (catabolic pathways

The mathematical expression for the change in free energy of a system is ΔG =ΔH - TΔS. Which of the following is (are) correct?

ΔS is the change in enthalpy, a measure of randomness.
ΔG is the change in free energy.
ΔH is the change in entropy, the energy available to do work.
T is the temperature in degrees Celsius.

A system at chemical equilibrium _____.

can do no work
consumes energy at a steady rate
releases energy at a steady rate
has zero kinetic energy

Which of the following is true for all exergonic reactions?

A net input of energy from the surroundings is required for the reactions to proceed.
The reaction proceeds with a net release of free energy.
The products have more total energy than the reactants.
The reaction goes only in a forward direction: all reactants will be converted to products, but no products will be converted to reactants.

A chemical reaction that has a positive ΔG is best described as _____.

exergonic
endergonic
spontaneous

Chemical equilibrium is relatively rare in living cells. An example of a reaction at chemical equilibrium in a cell would be _____.

a) one in which the entropy change in the reaction is just balanced by an opposite entropy change in the cell's surroundings
b) one in which the free energy at equilibrium is higher than the energy content at any point away from equilibrium
c) a chemical reaction in which both the reactants and products are not being produced or used in any active metabolic pathway at that time in the cell
d) an endergonic reaction in an active metabolic pathway where the energy for that reaction is supplied only by heat from the environment

Choose the pair of terms that correctly completes this sentence: Catabolism is to anabolism as _____ is to _____.

free energy; entropy
exergonic; spontaneous
exergonic; endergonic
work; energy

The following reaction
A --> B + C + heat
is a(n) _____ reaction.

exergonic
exchange
endergonic
dehydration synthesis
anabolic

A(n) _____ reaction occurs spontaneously.

chemical
anabolic
exergonic
endergonic
kinetic

Which of these reactions requires a net input of energy from its surroundings?

catabolic
endergonic
ATP --> ADP + P
exergonic
hydrolysis

In cells, what is usually the immediate source of energy for an endergonic reaction?

glucose
ADP
ATP
sugar
as spontaneous reactions, endergonic reactions do not need an addition of energy

The reaction ADP + P --> ATP is a(n) _____ reaction.

spontaneous
chemical
hydrolysis
endergonic
exergonic

The energy for an endergonic reaction comes from a(n) _____ reaction.

glucose + glucose --> maltose
synthesis
exergonic
anabolic
ADP + P --> ATP

What is the fate of the phosphate group that is removed when ATP is converted to ADP?

It is acquired by a reactant in an endergonic reaction.
It is acquired by a reactant in an exergonic reaction.
It is acquired by a reactant in a spontaneous reaction.
It is broken down into one phosphorus and four oxygen atoms.

Select the INCORRECT association.

exergonic ... spontaneous
exergonic ... uphill
potential energy ... positional energy
kinetic energy ... motion
enzyme ... protein

What is energy coupling?

a) the use of an enzyme to reduce EA
b) a description of the energetic relationship between the reactants and products in an exergonic reaction
c) a barrier to the initiation of a reaction
d) the use of energy released from an exergonic reaction to drive an endergonic reaction

Which of the following is most similar in structure to ATP?

a DNA nucleotide
an amino acid with three phosphate groups attached
an RNA nucleotide
a pentose sugar

When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated?

It is used to power yet more cellular work.
It is lost to the environment.
It is used to generate ADP from nucleotide precursors.
It is used to store energy as more ATP.

In general, enzymes are what kinds of molecules?

lipids
minerals
proteins
nucleic acids
carbohydrates

Enzymes work by _____.

a) increasing the potential energy difference between reactant and product
b) adding a phosphate group to a reactant
c) decreasing the potential energy difference between reactant and product
d) adding energy to a reaction
e) reducing EA

An enzyme _____.

increases the EA of a reaction
can bind to nearly any molecule
is a inorganic catalyst
is a source of energy for endergonic reactions
is an organic catalyst

What name is given to the reactants in an enzymatically catalyzed reaction?

substrate
EA
reactors
products
active sites

As a result of its involvement in a reaction, an enzyme _____.

loses a phosphate group
permanently alters its shape.
is used up
is unchanged
loses energy

Which of the following is true of enzymes?

a) Enzymes increase the rate of chemical reaction by lowering activation energy barriers.
b) Enzyme function is increased if the 3- D structure or conformation of an enzyme is altered.
c) Enzyme function is independent of physical and chemical environmental factors such as pH and temperature.
d) Enzymes increase the rate of chemical reaction by providing activation energy to the substrate.

Which of the following is true when comparing an uncatalyzed reaction to the same reaction with a catalyst?

The catalyzed reaction will consume all of the catalyst.
The catalyzed reaction will have higher activation energy.
The catalyzed reaction will be slower.
The catalyzed reaction will have the same G

The lock-and-key analogy for enzymes applies to the specificity of enzymes _____.

interacting with water
interacting with ions
as they form their tertiary and quaternary structure
binding to their substrate

The active site of an enzyme is the region that _____.

binds noncompetitive inhibitors of the enzyme
binds allosteric regulators of the enzyme
is inhibited by the presence of a coenzyme or a cofactor
is involved in the catalytic reaction of the enzyme

According to the induced fit hypothesis of enzyme catalysis, _____.

the active site creates a microenvironment ideal for the reaction
the binding of the substrate depends on the shape of the active site
some enzymes change their structure when activators bind to the enzyme
the binding of the substrate changes the shape of the enzyme's active site

Increasing the substrate concentration in an enzymatic reaction could overcome which of the following?

insufficient cofactors
competitive inhibition
the need for a coenzyme
allosteric inhibition

A noncompetitive inhibitor decreases the rate of an enzyme reaction by _____.

changing the shape of the enzyme's active site
acting as a coenzyme for the reaction
binding at the active site of the enzyme
changing the free energy change of the reaction

How might a change of one amino acid at a site, distant from the active site of an enzyme, alter an enzyme's substrate specificity?

by changing the shape of an enzyme
by changing the enzyme's pH optimum
by changing the enzyme's stability
An amino acid change away from the active site cannot alter the enzyme's substrate specificity.

The Haber process is typically carried out at a temperature of approximately 500∘C. What would happen to the rate of the forward reaction if the temperature were lowered to 100∘C?

What would happen to the rate of the forward reaction if the concentration of nitrogen were decreased?

Which of the following would increase the rate of the reverse reaction?
Hints

increasing the concentration of ammonia
decreasing the temperature
increasing the concentration of nitrogen

What will happen to the rates of the forward and reverse reactions when a catalyst is added?
Hints

Forward rate increases; reverse rate decreases.
Both forward and reverse rates increase.
Both forward and reverse rates decrease.
Forward rate decreases; reverse rate increases.

A (n)____________inhibitor has a structure that is so similar to the substrate that it can bond to the enzyme just like the substrate.

a _______________inhibitor binds to a site on the enzyme that is not the active site

The competitive inhibitor competes with the substrate for the ________ on the enzyme.

When the noncompetitive inhibitor is bonded to the enzyme, the shape of the_______ is distorted.

Enzyme inhibitors disrupt normal interactions between an enzyme and its_________.

You have added an irreversible inhibitor to a sample of enzyme and substrate. At this point, the reaction has stopped completely.
What can you do to regain the activity of the enzyme?


Removing the irreversible inhibitor should get the reaction working again.
The enzyme is inactive at this point. New enzyme must be added to regain enzyme activity.
Adding more substrate will increase the rate of reaction.
Adding more inhibitor should get the reaction up to speed again.

You have an enzymatic reaction proceeding at the optimum pH and optimum temperature. You add a competitive inhibitor to the reaction and notice that the reaction slows down.
What can you do to speed the reaction up again?

Add more inhibitor to speed up the reaction.
Add more substrate; it will outcompete the inhibitor and increase the reaction rate.
Increase the temperature.
Increase the pH.

A series of enzymes catalyze the reaction X → Y Z → A. Product A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme.


What is substance X?

a substrate
the product
an allosteric inhibitor

Allosteric enzyme regulation is usually associated with _____.

activating activity
the need for cofactors
an enzyme with more than one subunit
feedback inhibition

Besides turning enzymes on or off, what other means does a cell use to control enzymatic activity?

hydrophobic interactions
localization of enzymes into specific organelles or membranes
connecting enzymes into large aggregates
exporting enzymes out of the cell

totality of an organism's chemical reactions

release energy by breaking down complex molecules into simpler compounds