Deck 6: Energy and Metabolism

Question 1

Glucose is broken down through cellular respiration, which involves a large number of chemical reactions.At the end of the cellular respiration process, a large number of ATP molecules are generated, but yet, not all of the possible energy that is contained in a molecule of glucose can be harnessed through these chemical reactions to generate ATP.In other words, during cellular respiration, not all of the energy that is contained in a molecule of glucose is converted into the energy stored in ATP.What happens to the remaining energy?

A)It is destroyed
B)It is used to drive exergonic reactions
C)It is donated to molecules in the cellular respiration process to reduce them
D)It is lost as heat It is lost as heat.In fact, this is one of the ways we maintain our body temperature.

Answer 1

D

Question 2

Why do we have storage macromolecules, such as fats, in our bodies?

A)We can break down these macromolecules to provide energy for the endergonic reactions in our bodies.
B)Human cells can directly capture the energy of sunlight through photosynthesis and store it as macromolecules such as fats.
C)Macromolecules, such as fats, are a convenient way to store kinetic energy.
D)Breaking down macromolecules, such as fats, is an endergonic process.

Answer 2

A

Question 3

The energy needed to destabilize existing chemical bonds and start a chemical reaction is called

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

Answer 3

A

Question 4

A molecule that closely resembles the shape of a substrate for an enzyme would most likely serve as a

A)noncompetitive inhibitor.
B)allosteric inhibitor.
C)competitive inhibitor.
D)allosteric activator.

Question 5

The amount of energy available to do work is called

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

Question 6

The ultimate source of energy for humans comes from what source?

A)The sun
B)Plants
C)Water
D)Air

Question 7

Many metabolic pathways are ultimately concerned with ATP; either with the generation of ATP, or with the requirement of ATP for that pathway to function.Why is ATP so important to metabolism?

A)Hydrolysis of ATP is used to drive exergonic reactions
B)Hydrolysis of the bond between adenine and ribose in ATP is commonly used to release energy that can be used to drive other cellular reactions
C)The phosphate groups of ATP are held together by unstable bonds that can be broken to release energy
D)ATP is a protein that serves as the energy currency of cells ATP does serve as the energy currency of cells, by storing energy in its triphosphate group.By cleaving the unstable bonds holding the phosphates together in the ATP molecule, energy can be released to drive endergonic reactions.ATP can also be used as a building block for RNA molecules.It is not a protein.

Question 8

A particular reaction has a negative delta

A)This reaction does not obey the second law of thermodynamics
B)This reaction does not proceed spontaneously
C)The initial free energy of the reactants is much less than the final free energy of the products
D)A certain amount of activation energy is required for the reaction to proceed Reactions with a negative delta G proceed spontaneously, but not instantaneously.They need a certain amount of activation energy to proceed.

Question 9

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)passes electrons to many other types of molecules.

Question 10

The synthesis of sugar molecules through the process of photosynthesis requires energy absorbed from sunlight.Bearing this in mind, what kind of reaction is photosynthesis?

A)exergonic
B)endergonic
C)catabolic
D)feedback Because this process requires energy input, it is an endergonic reaction.

Question 11

A drug binds to the active site of an enzyme.If it is bound to the active site of the enzyme, it prevents substrate binding.This drug would be considered a

A)noncompetitive inhibitor.
B)allosteric inhibitor.
C)allosteric activator.
D)competitive inhibitor.

Question 12

Hexokinase is an enzyme that binds specifically to glucose and converts it into glucose 6-phosphate.The activity of hexokinase is suppressed by glucose 6-phosphate, which binds to hexokinase at a location that is distinct from the active site.This is an example of.

A)feedback inhibition.
B)competitive inhibition.
C)cofactor binding.
D)allosteric activation. In this case, the product of the reaction, glucose 6-phosphate, is feeding back to inhibit the enzyme that catalyzes the reaction, hexokinase.As a result, this is an example of feedback inhibition.

Question 13

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

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

Question 14

The chemistry of living systems representing all chemical reactions is called

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

Question 15

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

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

Question 16

A particular chemical reaction is exergonic.What can you say about the relationship between the reactants and the products in this exergonic reaction?

A)The reactants have more free energy than the products
B)The reactants are likely more disordered and the products are likely more ordered
C)The reactants cannot spontaneously react to generate the products
D)The reactants likely have lower enthalpy than the products

Question 17

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

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

Question 18

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

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

Question 19

Energy is defined as

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

Question 20

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

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

Question 21

In a chemical reaction, glyceraldehyde-3-phosphate + NAD⁺ yields 1,3-bisphosphoglycerate + NADH.In this reaction, what happened to NAD⁺?

A)It was oxidized to form NADH
B)It was reduced to form NADH
C)It was activated to form NADH
D)it served as an enzyme to catalyze the reaction, and at the end of the reaction formed NADH

Question 22

The Law of Thermodynamics that states that increases in entropy are favored is:

A)The First Law of Thermodynamics
B)The Second Law of Thermodynamics
C)The Third Law of Thermodynamics
D)The Fourth Law of Thermodynamics

Question 23

RNA molecules that also act as enzymes are given the name

A)ribozymes
B)cofactors
C)coenzymes
D)allosteric enzymes

Question 24

In an enzyme-catalyzed reaction, the reactant is called the

A)coenzyme
B)catalyst
C)substrate
D)product

Question 25

Glucose is converted into glucose 6-phosphate by hexokinase.Glucose 6-phosphate then serves as the substrate for the enzyme phosphoglucose isomerase, which converts this reactant into fructose 6-phosphate.Fructose 6-phosphate serves as the substrate for phosphofructokinase, which converts fructose 6-phosphate into fructose 1,6-bisphosphate.Based on the information provided, this is an example of what?

A)Feedback inhibition
B)Allosteric regulation
C)A metabolic pathway
D)Enzyme inhibition

Question 26

The Law of Thermodynamics that states that energy cannot be created or destroyed is:

A)The First Law of Thermodynamics
B)The Second Law of Thermodynamics
C)The Third Law of Thermodynamics
D)The Fourth Law of Thermodynamics

Question 27

A new antibiotic has been developed that inhibits the activity of an enzyme by competitive inhibition.What effect will this have on the activation energy of the enzyme-catalyzed reaction?

A)The activation energy required for the reaction in the presence of the antibiotic would be greater than the activation energy required in the absence of the antibiotic
B)The activation energy required for the reaction in the presence of the antibiotic would be less than the activation energy required in the absence of the antibiotic
C)The activation energy required for the reaction in the presence of the antibiotic will be the same as the activation energy required in the absence of the antibiotic

Question 28

You are studying an enzyme-catalyzed reaction that induces a particular cellular activity in the lab.If you wanted to slow down that particular cellular activity by controlling the enzyme, what could you do?

A)Decrease the temperature of the incubator where the cells are growing
B)Increase the pH of the media the cells are growing in to the optimum pH
C)Add cofactors to the media the cells are growing in
D)Add an allosteric activator to the cells Decreasing the temperature could work to slow down the reaction.All of these other choices would either increase or maintain the rate of the reaction.

Question 29

Does ADP contain the capacity to provide energy for the cell?

A)No.ADP does not contain any bonds that can be broken to provide energy for the cell.
B)Yes.ADP has the same capacity to provide energy for the cell as ATP.
C)Yes.Cleaving the bond between the ribose sugar and the two phosphate groups can provide energy for the cell.
D)Yes.Cleaving the bond between the terminal phosphate and the phosphate attached to the ribose sugar can provide energy for the cell.

Question 30

A current problem in modern medicine is the development of drug resistance mutations.This occurs when a mutation arises in a disease-causing microbe making it resistant to a drug and thus rendering the drug useless in treating a specific disease.Many useful drugs are competitive inhibitors of specific enzymes, and the drug-resistance mutations prevent the binding of the drug.These types of mutations, in addition to preventing competitive inhibitor binding, can also sometimes reduce the activity of the enzyme.Why is that the case? rev: 01_20_2015_QC_CS-4567

A)Binding to the competitive inhibitor is essential for the function of the enzyme
B)These mutations most likely affect an allosteric site on the enzyme
C)These mutations lower the activation energy of the reaction catalyzed by the enzyme
D)These mutations most likely change the shape of the active site of the enzyme

Question 31

You are working with a specific enzyme-catalyzed reaction in the lab.You are a very careful experimentalist, and as a result, at the beginning of each of your experiments, you measure the temperature in the lab.On days 1 through 5, the temperature in the lab was 20^oC.Today is day 6 of your experiment, and the temperature in the lab is 30^oC.How do you predict that this will alter the rate of your enzyme-catalyzed reaction?

A)It will decrease the rate
B)It will increase the rate
C)It could possibly increase or decrease the rate
D)it will not affect the rate

Question 32

In order to reuse an enzyme after the conclusion of an enzyme catalyzed reaction, what must occur?

A)the enzyme has to be resynthesized
B)the enzyme has to separate itself from the product
C)changes into an active form
D)the enzyme has to decrease entropy

Question 33

Tacrolimus (FK-506) is a drug that inhibits an enzyme called calcineurin.Calcineurin is a protein phosphatase.This is an enzyme that dephosphorylates (removes phosphate groups) from proteins.When added to cells, tacrolimus can inhibit the dephosphorylation of a protein called NFAT, but it cannot prevent the dephosphorylation of a protein called CDK1.What is the most likely explanation for this finding?

A)Calcineurin requires an additional cofactor to dephosphorylate NFAT
B)NFAT is a substrate of calcineurin, but CDK1 is not
C)Tacrolimus is a competitive inhibitor of calcineurin for NFAT and CDK11
D)Tacrolimus changes the optimum pH for calcineurin

Question 34

A new antibiotic has been developed.It acts as a noncompetitive inhibitor.How will this antibiotic affect delta G for the enzyme-catalyzed reaction?

A)Delta G will increase
B)Delta G will decrease
C)Delta G will be unaffected

Question 35

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)different amounts of energy depending on the cell.

Question 36

For a particular chemical reaction, the enthalpy of the reactants is -400 kJ.The enthalpy of the products is -390 kJ.The entropy of the reactants is 0.2 kJ/K.The entropy of the products is 0.3 kJ/K.The temperature of the reaction is 25 degrees Celsius.What can you conclude about this reaction?

A)It is exergonic
B)It is endergonic
C)it is a redox reaction
D)It is being catalyzed by an enzyme

Question 37

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

A)an 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

Question 38

In a chemical reaction, 1,3-bisphosphoglycerate + ADP yields 3-phosphoglycerate plus ATP.What is the delta G for this reaction?

A)Greater than zero.
B)Less than zero.
C)Equal to zero.
D)Cannot be determined

Question 39

AMP-activated protein kinase (AMPK) is an enzyme that is activated by high levels of AMP in cells.If levels of AMP are high in cells, that means that levels of ATP are low.Once active, AMPK activates catabolic pathways and inhibits anabolic pathways in the cell.Why do you think that is the case? Choose the answer that best explains the role of AMPK.

A)High levels of AMP indicate that there is a high amount of energy stored in the cell, thus activating catabolic pathways and inhibiting anabolic pathways are mechanisms to use stored energy.
B)By inhibiting anabolic pathways, AMPK provides a mechanism to generate heat for the cell, which is important if AMP levels are high in the cell.
C)By activating catabolic pathways, AMPK provides a mechanism to activate exergonic pathways, which is important if AMP levels are high in the cell.
D)Activating catabolic pathways and inhibiting anabolic pathways will ultimately lead to higher consumption of ATP, which is important if AMP levels are high in the cell.

Question 40

Metabolic reactions fall under two general categories: anabolic and catabolic.What type of chemical reactions are these two classes of metabolic reactions?

A)Anabolic reactions are exergonic reactions, whereas catabolic reactions are endergonic.
B)Both anabolic and catabolic reactions are exergonic.
C)Both anabolic and catabolic reactions are endergonic.
D)Anabolic reactions are endergonic reactions, whereas catabolic reactions are exergonic.

Question 41

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

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

Question 42

Phosphofructokinase (PFK) is an enzyme that converts fructose 6-phosphate to fructose 1,6-bisphosphate, by adding a phosphate group.This is the first committed step of the metabolic pathway of glycolysis, and thus it is very tightly regulated.AMP binds to PFK at a site distinct from the binding site for fructose 6-phosphate, and stimulates the formation of fructose 1,6-bisphosphate.ATP binds to PFK at a site distinct from the binding site for fructose 6-phosphate, and inhibits the formation of fructose 1,6-bisphosphate.There are other regulators of this enzyme as well.What is the role of AMP in this example?

A)Competitive inhibitor
B)Noncompetitive inhibitor
C)Allosteric inhibitor
D)Allosteric activator

Question 43

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

A)It would increase
B)It would decrease
C)It would remain the same

Question 44

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)80 Joules

Question 45

It is summer, and you are excited about going to your local amusement park, and specifically about riding the new roller coaster that was just built.You imagine waiting at the top of the stairs for the roller coaster to pull into the station, climbing into the car, strapping yourself into the seatbelt, and pulling down the harness.You can imagine the cars slowly chugging up to the top of the first hill, coming down on the other side, and the excitement you expect to feel as you go along for the ride.Of all of the things that you have imagined, which is an example of potential energy?

A)Waiting at the top of the stairs for the roller coaster to pull into the station
B)Climbing into the car
C)Pulling down the harness
D)The roller coaster car going up the first hill

Question 46

You eat a bowl of beans as part of your dinner.As you digest the beans, the proteins that are present get broken down to their component amino acids.As your body destroys the macromolecules that were present in the beans, is the energy present in those molecules destroyed?

A)Yes.By breaking down these macromolecules, some of the energy they contained is destroyed.
B)No.While the vast majority of the energy contained in these macromolecules is converted to heat, it is not actually destroyed.
C)No.The energy contained within these macromolecules is converted into other forms of chemical energy and kinetic energy, though some is lost as heat.
D)No.Breaking down molecules does not lead to the release of energy.

Question 47

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 48

Enzyme 1 converts substrate A into product

A)Yes.This is a metabolic pathway that includes feedback inhibition.
B)Is this an example of a metabolic pathway?
B)No.This only describes one chemical reaction.A metabolic pathway includes multiple chemical reactions.
C)Yes.This is a simple metabolic pathway.

Question 49

Glycolysis is a metabolic process that is done by all cells.However, not all cells make use of another metabolic process called the Krebs cycle.What does this tell you about the evolution of these processes?

A)As a metabolic process, glycolysis likely evolved prior to the Krebs cycle
B)As a metabolic process, the Krebs cycle likely evolved prior to glycolysis
C)Both the Krebs cycle and glycolysis likely evolved at the same time

Question 50

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

A)the products have more free energy than the reactants.
B)the reaction requires an energy input of 31.45 kJoules to proceed.
C)the reaction most likely leads to development of a more ordered system.
D)the reaction is spontaneous.

Question 51

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 52

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

A)Add a non-competitive inhibitor to the reaction.
B)Add a cofactor to the reaction.
C)Increase the concentration of the correct substrate in the reaction.
D)Add an allosteric activator to the reaction.