Question 1

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

Accepted Answer

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

Question 2

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

Accepted Answer

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 
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 D

Question 3

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

Accepted Answer

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 
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 A

Question 4

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

Accepted Answer

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. 
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 5

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?

Accepted Answer

A) 0 Joules 
B) 20 Joules 
C) 40 Joules 
D) 80 Joules 
A) 0 Joules 
B) 20 Joules 
C) 40 Joules 
D) 80 Joules

Question 6

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?

Accepted Answer

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

Question 7

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?

Accepted Answer

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 
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 8

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 20oC.Today is day 6 of your experiment, and the temperature in the lab is 30oC.How do you predict that this will alter the rate of your enzyme-catalyzed reaction?

Accepted Answer

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 
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 9

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

Accepted Answer

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. 
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.

Question 10

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:

Accepted Answer

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

Question 11

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?

Accepted Answer

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 
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 12

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

Accepted Answer

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

Question 13

RNA molecules that also act as enzymes are given the name

Accepted Answer

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

Question 14

The chemistry of living systems representing all chemical reactions is called

Accepted Answer

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

Question 15

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.

Accepted Answer

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. 
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 16

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?

Accepted Answer

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

Question 17

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

Accepted Answer

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

Question 18

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

Accepted Answer

A) The First Law of Thermodynamics 
B) The Second Law of Thermodynamics 
C) The Third Law of Thermodynamics 
D) The Fourth Law of Thermodynamics 
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 19

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?

Accepted Answer

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 
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 20

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

Accepted Answer

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

Exam 6: Energy and Metabolism

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

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

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

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?

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

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 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?

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

RNA molecules that also act as enzymes are given the name

The chemistry of living systems representing all chemical reactions is called

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

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

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

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