Deck 6: Energy and Metabolism

Question 1

Certain key molecules can regulate biochemical pathways by controlling the rates of enzymatic reactions by binding at _________ sites.

A)catalytic
B)enzymatic
C)active
D)allosteric

Answer 1

D

Question 2

The chemistry of living systems representing all chemical reactions is called

A)catabolism.
B)anabolism.
C)metabolism.
D)enzymology.
E)thermodynamics.

Answer 2

C

Question 3

A series of sequential chemical reactions which are maintained in the cell are called:

A)chemical reactions
B)biochemical pathways
C)energy steps
D)second messenger cascades

Answer 3

B

Question 4

A molecule that closely resembles the shape of a substrate for an enzyme might serve as a(n)

A)an enzyme
B)allosteric modulator
C)competitive inhibitor
D)pathway blocker

Question 5

A calorie is the commonly used unit of chemical energy.It is also the unit of

A)light.
B)magnetism.
C)sound.
D)heat.
E)radioactivity.

Question 6

Enzymes have specific ________ with which they interact.

A)products
B)substrates
C)reactants
D)atoms
E)end-products

Question 7

The inorganic non-protein components that participate in enzyme catalysis are known as

A)coenzymes.
B)cofactors.
C)end-products.
D)substrates.
E)reactants.

Question 8

Energy is defined as:

A)heat
B)the capacity to do work
C)change
D)movement

Question 9

A chemical reaction in which the products contain less energy than the _______ will tend to proceed spontaneously.

A)reactants
B)enzymes
C)coenzymes
D)substrates
E)cofactors

Question 10

Enzymes work most effectively at

A)their optimum pH and temperature conditions
B)all pH and temperature conditions
C)only one temperature and a specific pH

Question 11

The specificity of an enzyme is due to its active site.The active site is shaped so that only a certain

A)substrate molecule can fit into it.
B)product molecule can fit into it.
C)reactant molecule can fit into it.
D)cofactor molecule can fit into it.
E)histone molecule can fit into it.

Question 12

A chemical reaction which requires energy is called an ________________ reaction.

A)exergonic
B)endergonic
C)explosive
D)heating

Question 13

Oxidation and reduction reactions are chemical processes that result in a gain or loss in

A)atoms.
B)neutrons.
C)electrons.
D)molecules.
E)protons.

Question 14

Each of the significant properties of a cell (its growth,reproduction,and responsiveness to its environment)requires ________.

A)energy
B)light
C)mitosis
D)movement

Question 15

Protein catalysts that speed up the various metabolic biological reactions in an organism are called

A)substrates.
B)cofactors.
C)reactants.
D)products.
E)enzymes.

Question 16

The process of influencing the chemical bonds in a way that lowers the __________ needed to speed up a chemical reaction is called catalysis.

A)heat energy
B)free energy
C)activation energy
D)enzyme

Question 17

Free energy is the amount of energy available for the cell to carry out its many chemical processes.It is the difference between the internal energy or enthalpy and ______ or disorder.

A)free energy
B)entropy
C)chaos
D)heat

Question 18

The organic non-protein components that aid in enzyme functioning are called

A)reactants.
B)cofactors.
C)coenzymes.
D)substrates.
E)products.

Question 19

Reactions that occur spontaneously and release free energy are called _____________ reactions.

A)activation
B)exergonic
C)catabolistic
D)thermodynamic
E)endergonic

Question 20

The chief energy currency of all cells is a molecule called

A)cyclic AMP.
B)NADH.
C)FADH.
D)ATP.
E)ADP.

Question 21

Enzymes catalyze chemical reactions by lowering the

A)entropy.
B)free energy.
C)activation energy.
D)enthalpy.
E)calories.

Question 22

Enzymes are very specific in their choices of substrates because each different enzyme has an active site that

A)depends on unusual amino acids not common in proteins.
B)has a certain unique amino acid to fit each substrate.
C)is shaped to fit a certain substrate molecule.
D)is lined with glycolipids and glycoproteins.
E)passes electrons from one part of the substrate to another.

Question 23

ATP gives up energy when it is converted to

A)DNA.
B)NADP.
C)NADH.
D)ADP and phosphate.
E)RNA.

Question 24

The sites where molecules other than substrates bind in an enzyme to alter its activity are called ____________ sites.

A)catalytic
B)allosteric
C)metabolic
D)amino acid
E)activity

Question 25

When an atom or molecule gains one or more electrons,it is said to be

A)energized.
B)oxidized.
C)polarized.
D)activateD.
E)reduced.

Question 26

Reactions that do not proceed spontaneously because they require energy from an outside source are called

A)exergonic.
B)xerogonic.
C)metaboliC.
D)endergonic.
E)endocytic.

Question 27

One of the most important coenzymes that accepts electrons/hydrogens is

A)NAD⁺.
B)NADH.
C)ATP.
D)NADPH.
E)ribozymE.

Question 28

The regulation of simple biochemical pathways often involves the end-product binding to the allosteric site of the first enzyme in the sequence.This mode of regulation is called

A)competitive inhibition.
B)biochemical regulation.
C)cellular control.
D)product catalysis.
E)feedback inhibition.

Question 29

The ability of an enzyme to catalyze a reaction is not affected by

A)temperature.
B)pH.
C)salt concentration.
D)binding of specific regulatory molecules.
E)excess cofactor.

Question 30

As energy is being reconverted through the many forms,it is continuously lost as

A)electricity.
B)light.
C)sound.
D)heat.
E)chemical energy.

Question 31

Molecules that act as catalysts in biological systems are

A)ATP.
B)cofactors.
C)coenzymes.
D)enzymes.
E)genes.

Question 32

The First Law of Thermodynamics simply states that

A)energy is constantly being created in the universe.
B)disorder in the universe is continually increasing.
C)energy can be created but not destroyed.
D)energy cannot be created or destroyed,just changed from one form to another.
E)energy can be recycled through the universE.

Question 33

In an enzyme catalyzed reaction the reactant is called the

A)ribozyme.
B)catalyst.
C)substrate.
D)end-product.
E)activator.

Question 34

When the substrate is bound to the enzyme,the shape of the enzyme may change slightly,leading to

A)a better induced fit.
B)a great range of possible catalytic activities.
C)a greater supply of activation energy.
D)more permanent binding through intimate total contact.
E)more possible products of the reaction.

Question 35

Life's ultimate source of energy is derived from

A)the sun.
B)plants.
C)water.
D)air.
E)cells.

Question 36

At the conclusion of an enzyme catalyzed reaction,the enzyme

A)must be resynthesized from its amino acids.
B)frees itself from the product and is ready to be reused.
C)must be transported from outside of the cell.
D)changes into an active form.
E)closes up its active site and cannot bind to more substratE.

Question 37

RNA molecules that have been recently reported to act also as enzymes are given the name

A)ribozymes.
B)deoxyribozymes.
C)chromosomes.
D)coenzymes.
E)metalloenzymes.

Question 38

The term oxidation is derived from the name of the element oxygen.This is reasonable,because oxygen

A)attracts electrons very strongly.
B)can be oxidized by accepting electrons.
C)contains more electrons than are needed.
D)can react chemically readily in its gas state.
E)is present everywherE.

Question 39

Most protein-enzymes are

A)fibrous proteins.
B)hormones.
C)histones.
D)metalloenzymes.
E)globular proteins.

Question 40

Under standard conditions,ATP can release for every molecule converted to ADP

A)less than 1 cal of energy.
B)1 to 2 cal of energy.
C)7.3 Kcal of energy.
D)7.3 cal of energy.
E)different amounts of energy depending on the cell.

Question 41

Which of the following best depicts a diagram of enzymes and substrates when they react? Assume only forward reactions.Use the following to make your choice: E = enzyme,S = substrate,ES = enzyme-substrate complex,P = products.

A)E + P $\rarr$ ES
B)E + S $\rarr$ ES + P
C)E + S $\rarr$ ES $\rarr$ E + P
D)E + ES $\rarr$ P + E
E)E + P $\rarr$ EP $\rarr$ S + E

Question 42

In a chemical reaction in a living system,enzymes are used as catalysts.Which of the following statements about enzymes is incorrect?

A)Enzymes enter reactions and can be reused.
B)Enzymes speed up chemical reactions in living systems.
C)Enzymes reduce the energy of activation necessary for a chemical reaction to go forward.
D)Enzymes increase the energy of activation necessary for a chemical reaction to go forwarD.
E)Enzymes are sometimes referred to as biological catalysts;however,not all biological catalysts are proteins.

Question 43

The temperature is raised slightly above the optimum for a specific enzyme.What would you expect to observe as a result of the change in temperature?

A)increased enzyme activity
B)decreased enzyme activity
C)no change in enzyme activity
D)enzyme denaturation

Question 44

If you were able to increase the kinetic energy of the molecules inside your body,your body temperature would

A)increase.
B)decrease.
C)remain the same.

Question 45

Which of the following statements about the equilibrium constant of a chemical reaction is false?

A)The equilibrium constant depends on the concentrations of the reactants and products.
B)An endergonic reaction has an equilibrium constant that favors the products.
C)The equilibrium constant of a reaction is influenced by temperature.
D)The equilibrium constant of a reaction has a numerical value.

Question 46

A new antibiotic has been developed that will use noncompetitive inhibitor enzyme inhibition.This means that the

A)antibiotic will bind to the enzyme and alter the shape of the enzyme.
B)antibiotic will bind to the substrate and alter the shape of the substrate.
C)antibiotic will bind to the enzyme-substrate complex and alter its shape.
D)antibiotic will bind to the product that is being produced and alter its shape.
E)antibiotic will bind to the receptor proteins embedded in the phospholipid bilayer,which will in turn close the channels.

Question 47

Which of the following statements concerning redox reactions are false?

A)The reduced form of a molecule has a higher level of energy than the oxidized form.
B)Reduction is the gain of an electron,and oxidation is the loss of an electron.
C)Organisms can derive energy from the oxidation of organic compounds.
D)Oxidation reactions and reduction reactions occur independently.

Question 48

While standing at the top of the stairs,you have a potential energy of 40 Joules.If you walk all the way down the stairs,what would your potential energy be at the bottom of the stairs?

A)0 Joules
B)20 Joules
C)40 Joules
D)cannot determine from the information provided

Question 49

You return home to find that your baby brother has scattered his toy trains and trucks all over the floor of your room.As you begin to pick up the toys and put them away,you realize that even though he is just a baby,he has clearly mastered

A)the first law of thermodynamics.
B)the second law of thermodynamics.
C)potential energy.
D)free energy.

Question 50

The substance on which the enzyme works;the raw material of the reaction.

A)active site
B)substrate
C)coenzyme
D)non-catalytic binding site

Question 51

If you were an enzyme and needed to perform the energetically unfavorable conversion of X to Y,you would

A)couple it to a second reaction associated with a large decrease in free energy.
B)couple it to a second reaction associated with a large increase in free energy.
C)couple it to the formation of ATP from ADP and P_i.
D)couple it to an endergonic reaction.

Question 52

If the $\Delta$ G of a reaction was -31.45 kJoules,you would know that

A)the reaction would proceed spontaneously.
B)the reaction requires an energy input of 31.45 kJoules to proceed.
C)the products of the reaction have more free energy than the reactants.
D)it is an energonic reaction.

Question 53

A new antibiotic has been developed that will use competitive inhibitor enzyme inhibition.This means that the

A)antibiotic will compete for substrate binding sites on the enzyme.
B)antibiotic will compete for binding sites on the substrate.
C)antibiotic will compete for binding sites on the enzyme-substrate complex.
D)antibiotic will compete for binding sites on the product that is being produceD.
E)antibiotic will only compete for binding sites on the receptor proteins embedded in the phospholipid bilayer.

Question 54

One type of biochemical pathway regulation is referred to as feedback inhibition.This means that as the

A)cell produces more quantity of product through a biochemical pathway,the build up of that product will inhibit the activity of that product's production.
B)cell produces more quantity of product through a biochemical pathway,the activity will be increased or stimulated by the build up of that product.
C)cell produces less quantity of product through a biochemical pathway,the activity will be inhibited by not having enough of that product.
D)cell produces less quantity of product through a biochemical pathway,the activity of the substrate will be increased and that it will exceed capacity of the pathway.

Question 55

A researcher wants to slow down a particular cellular activity by controlling an enzyme that catalyzes that activity.All of the following choices are available except

A)increasing the temperature of the cell's environment.
B)decreasing the temperature of the cell's environment.
C)reducing the pH of the cell's environment.
D)increasing the pH of the cell's environment.
E)adding substrate as it is depleted to the cell's environment.

Question 56

Allosteric inhibitor binds here;changes enzyme shape.

A)active site
B)substrate
C)coenzyme
D)non-catalytic binding site

Question 57

Part of the complete enzyme;nonprotein,organic component.

A)active site
B)substrate
C)coenzyme
D)non-catalytic binding site

Question 58

Spot where raw material binds and is changed to product.

A)active site
B)substrate
C)coenzyme
D)non-catalytic binding site

Question 59

The Gibbs free energy equation,G = H - TS,interrelates

A)free energy and entropy.
B)free energy and enthalpy.
C)free energy and standard temperature.
D)entropy and enthalpy.

Question 60

The Second Law of Thermodynamics simply states that

A)energy can be recycled through the universe.
B)energy cannot be created or destroyed,just changed from one form to another.
C)disorder (or entropy)in the universe is continually increasing.
D)energy is constantly being created in the universe.
E)energy can be created but not destroyed.

Question 61

A ribozyme catalyzes a reaction on itself and actually changes shape.This is an example of

A)intra-enzyme reactions
B)inter-enzyme reactions
C)intramolecular catalysis
D)intermolecular catalysis

Question 62

After getting off the ski lift,you choose a trail that requires you to ski up a small incline before beginning the downward section of the trail.In this scenario,the hill is analogous to

A)free energy.
B)potential energy.
C)kinetic energy.
D)activation energy.

Question 63

In the hypothetical biochemical pathway,P $\rarr$ Q + R $\rarr$ S $\rarr$ T,which step is likely to have evolved first?

A)P $\rarr$ Q
B)Q + R
C)R $\rarr$ S
D)S $\rarr$ T

Question 64

Shivering is the result of uncontrollable contractions of skeletal muscle tissue in an effort to increase heat production and raise body temperature.How does this process relate to ATP hydrolysis?

A)ATP is converted directly to heat.
B)Muscle contractions in the form of shivering produces heat and warms the body.
C)ATP hydrolysis causes muscle contraction.
D)Muscle contractions require ATP hydrolysis.Energy is liberated by ATP hydrolysis and converted into heat.

Question 65

Which of the following scenarios would not result in a decrease in free energy?

A)Enthalpy increases and entropy decreases.
B)Enthalpy decreases and entropy increases.
C)Enthalpy increases,but entropy increase outweighs increase in enthalpy.
D)Enthalpy decreases enough to outweigh a slight decrease in entropy.

Question 66

Hemoglobin is a protein composed of four subunits,each with a binding site for oxygen.When a molecule of O₂ binds to any one of the subunits,the affinity of the other three subunits for O₂ is increased.What role is oxygen playing in this process?

A)enzyme
B)allosteric activator
C)allosteric inhibitor
D)substrate

Question 67

While conducting an experiment,you realize that a competitive inhibitor was interfering with your reaction.To overcome this problem,you

A)add a non-competitive inhibitor to the reaction.
B)decrease the concentration of the correct substrate in the reaction.
C)increase the concentration of the correct substrate in the reaction.
D)add an allosteric activator to the reaction.

Question 68

Which of the following statements about ATP hydrolysis is false?

A)The bonds between the phosphates in ATP are high-energy bonds.
B)A large amount of free energy is released as a result of ATP hydrolysis.
C)ATP hydrolysis has a $\Delta$ G of 7.3 kcal/mol.
D)The bonds between the phosphates in ATP are unstable.