Deck 10: Introduction to Metabolism

Question 1

Cells carry out three major types of work; which of the following involves the synthesis of macromolecules as well as the breakdown of substances for their energy?

A)Chemical work
B)Transport work
C)Mechanical work
D)None of the choices are correct.

Answer 1

A

Question 2

Disruption of an enzyme's structure with loss of activity caused by extremes of pH,temperature,or other factors is called _________.

Answer 2

denaturation

Question 3

__________ is the science that analyzes energy changes in a collection of matter.

Answer 3

Thermodynamics

Question 4

Energy can be redistributed within a collection of matter (called a system)or can be redistributed between the system and its surroundings.

Question 5

Cells carry out three major types of work; which of the following involves energy for cell motility and the movement of structures within cells?

A)Chemical work
B)Transport work
C)Mechanical work
D)None of the choices are correct.

Question 6

RNA molecules that have catalytic activity are known as ____________.

Question 7

The __________ __________ is the substrate concentration needed for an enzyme to achieve half maximal velocity.

Question 8

__________ reactions capture energy from the organisms' energy source.

Question 9

_________ is the total of all chemical reactions occurring in the cell.

Question 10

The molecules formed by an enzyme-catalyzed reaction are called __________.

Question 11

The reacting molecules in an enzyme-catalyzed reaction are called __________.

Question 12

A molecule that binds noncovalently to an enzyme at the active site and thereby prevents a substrate from binding and reacting is a(n)__________ inhibitor.

Question 13

A molecule that binds to an enzyme at a location other than the active site and thereby alters the enzyme's shape,making it inactive or less active is a(n)__________ inhibitor.

Question 14

Cells carry out three major types of work; which of the following involves nutrient uptake and waste elimination?

A)Chemical work
B)Transport work
C)Mechanical work
D)None of the choices are correct.

Question 15

In order for the cell to be able to input energy into necessary endergonic reactions,energy-generating processes such as photosynthesis,fermentation,and respiration are used to produce __________.

Question 16

A complex formed during a reaction that resembles both the substrates and the products is called the __________ state complex.

Question 17

________ reactions build new organic molecules from smaller inorganic and organic compounds.

Question 18

Cells must efficiently transfer energy from their energy-trapping systems to the systems actually carrying out work and also use various metabolic processes to replace the energy used in doing work.This is called the __________ ______________.

Question 19

A reaction in which the forward rate is equal to the reverse rate is said to be at __________.

Question 20

In thermodynamic studies,energy changes are analyzed in a collection of matter called a __________.All other matter in the universe is called the __________.

Question 21

Electron transport molecules that only transfer electrons include

A)ubiquinone.
B)NADP.
C)FAD.
D)ferredoxin.

Question 22

The amount of heat energy needed to raise 1 gram of water from 14.5 ^$\circ$ C to 15.5 ^$\circ$ C is called a(n)

A)joule.
B)calorie.
C)erg.
D)thermal unit.

Question 23

The most commonly used practical form of energy used in cells is adenosine diphosphate.

Question 24

The __________ is the electron acceptor in a redox reaction.

A)reductant
B)oxidant
C)enzyme
D)product

Question 25

__________ is the total energy change that accompanies a chemical reaction.

A)Entropy
B)Enthalpy
C)Free energy
D)Synergy

Question 26

The electron transport chain is based on the principle that redox couples with more positive reduction potentials will donate electrons to couples with more negative potentials.

Question 27

The change in __________ is the amount of energy in a system that is available to do work.

A)entropy
B)enthalpy
C)free energy
D)synergy

Question 28

The __________ is the electron donor in a redox reaction.

A)reductant
B)oxidant
C)enzyme
D)product

Question 29

The equilibrium constant for a redox reaction is called the standard reduction potential.

Question 30

Which of the following is used as an electron carrier by living organisms?

A)NAD⁺
B)NADP⁺
C)Ubiquinone
D)All of the choices are correct.

Question 31

An chemical reaction that requires an input of energy in order to proceed is __________.

A)exergonic
B)endergonic
C)impossible
D)None of the choices are correct.

Question 32

A reaction that releases energy is __________.

A)exergonic
B)endergonic
C)impossible
D)None of the choices are correct.

Question 33

Some endergonic reactions can be made to proceed forward if they are coupled to hydrolysis of one or more of the phosphates of ATP.

Question 34

__________ is a measure of the randomness or disorder of a system.

A)Entropy
B)Enthalpy
C)Free energy
D)Synergy

Question 35

The __________ law of thermodynamics states that physical and chemical processes occur in such a way that randomness (disorder)increases to a maximum.

A)first
B)second
C)third
D)fourth

Question 36

The numerical value of the free energy change indicates how fast a reaction will reach equilibrium.

Question 37

For the reaction A + B $\rarr$ C + D,the equilibrium constant (Keq)is expressed as

A)[A][B]/[C][D].
B)[C][D]/[A][B].
C)[A][D]/[B][C].
D)[B][C]/[A][D].

Question 38

The standard reduction potential of a redox reaction is a measure of the tendency of the __________ to __________ electrons.

A)reductant; gain
B)reductant; lose
C)oxidant; gain
D)oxidant; lose

Question 39

The __________ law of thermodynamics states that energy can be neither created nor destroyed.

A)first
B)second
C)third
D)fourth

Question 40

One of the components used during photosynthetic electron transport is ferredoxin,a nonheme iron protein.

Question 41

Enzymes increase the rate of a reaction but do not alter equilibrium constants.

Question 42

The Michaelis constant (Km)of an enzyme is the substrate concentration that produces maximum velocity.

Question 43

Enzymes increase the rate of a reaction by increasing molecular motion,thereby providing kinetic energy to drive the reaction.

Question 44

If all available enzyme molecules are binding substrate and converting it to product as rapidly as possible,the reaction is said to be proceeding at __________ velocity.

A)terminal
B)maximal
C)optimal
D)infinite

Question 45

A(n)_______________ increases the rate of a reaction without being permanently altered by the reaction.

A)catalyzer
B)catalyst
C)enzyme
D)rate increaser

Question 46

The most specific term usually used to describe a substance in a biological system that increases the rate of a reaction without being permanently changed by the reaction is a(n)

A)catalyzer.
B)catalyst.
C)enzyme.
D)rate increaser.

Question 47

Enzyme activity can be greatly affected by the pH and the temperature of the environment in which the enzyme must function.

Question 48

Enzymes are usually named based on

A)the substrates they act on.
B)their molecular structure.
C)the type of reaction they catalyze.
D)All of the choices are correct.
E)the substrates they act on and the type of reaction they catalyze.

Question 49

Which of the following is/are true about enzymes?

A)Enzymes are catalysts that speed up reactions.
B)Enzymes are proteins that can be denatured by changes in pH or temperature.
C)Enzymes are highly specific for the substrates they react with and catalyze only one or a limited set of possible reactions with those substrates.
D)All of the choices are correct.

Question 50

The energy required to bring the substrates of a reaction together in the correct way to reach the transition state is called

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

Question 51

Each enzyme normally has specific pH and temperature optima at which they function best.

Question 52

A nonprotein component of an enzyme that is loosely attached to the protein component is referred to as a(n)

A)apoenzyme.
B)coenzyme.
C)holoenzyme.
D)prosthetic group.

Question 53

One important ribozyme located in mitochondria is responsible for catalyzing peptide bond formation during protein synthesis.

Question 54

The substrate of an enzyme binds at the

A)affinity site.
B)active site.
C)determinative site.
D)reaction site.

Question 55

The nonprotein component of an enzyme that is firmly attached to the protein is called a(n)

A)apoenzyme.
B)coenzyme.
C)holoenzyme.
D)prosthetic group.

Question 56

A complete enzyme that consists of a protein component and a nonprotein component is called a(n)

A)apoenzyme.
B)heteroenzyme.
C)holoenzyme.
D)multienzyme.

Question 57

Enzymes function as catalysts by

A)bringing the substrates together at the active site,in effect concentrating them.
B)bringing the substrates together at the active site correctly oriented for the reaction.
C)bringing the substrates together at the active site,in effect concentrating them and bringing the substrates together at the active site correctly oriented for the reaction.
D)None of the choices are correct.

Question 58

When the amount of enzyme present is held constant,the rate of a reaction will continue to increase as long as the substrate concentration increases.

Question 59

If an enzyme consists of a protein component and a non-protein component,the protein component is referred as the

A)apoenzyme.
B)coenzyme.
C)holoenzyme.
D)prosthetic group.

Question 60

Enzymes catalyze a reaction by

A)decreasing the amount of energy released by the reaction.
B)increasing the amount of energy released by the reaction.
C)decreasing the activation energy of the reaction.
D)increasing the activation energy of the reaction.

Question 61

In metabolic channeling,the regulation of metabolic pathways is controlled by the __________ of metabolites and enzymes involved in the pathway.

A)amount
B)location
C)activity
D)All of the choices are correct.

Question 62

ATP has a phosphate transfer potential of 30.5,whereas glucose-6-phosphate has a phosphate transfer potential of 13.8.Based on these differences,which of the following will happen?

A)ATP will transfer phosphate to glucose-6-phosphate.
B)Glucose-6-phosphate will transfer phosphate to ADP forming ATP.
C)Phosphates will not be transferred between these molecules.
D)ATP will transfer phosphate to phosphoenolpyruvate.

Question 63

Arrange the following electron carriers in the electron transport chain,based on their standard reduction potentials. Cytochroms a₃(Fe³⁺⁾ + e^- $\rarr$ Cytochrome a₃ (Fe²⁺)E_o (volts)= 0.35
Ubiquinone + 2H⁺ + 2e^- $\rarr$ Ubiquinone H₂ E_o (volts)= 0.10
Cytochrome a (Fe³⁺⁾ + e^- $\rarr$ Cytochrome a (Fe²⁺)E_o (volts)= 0.29
Cytochrome c (Fe³⁺⁾ + e^- $\rarr$ Cytochrome c (Fe²⁺)E_o (volts)= 0.25

A)ubiquinone - cytochrome c- cytochrome a- cytochrome a₃
B)cytochrome a₃ - cytochrome a - cytochrome c - ubiquinone
C)ubiquinone - cytochrome a - cytochrome a₃ - cytochrome c
D)cytochrome c - ubiquinone - cytochrome a - cytochrome a₃

Question 64

Metabolic channeling involves the localization of __________ in different parts of a cell in order to influence the activity of metabolic pathways.

A)activators
B)repressors
C)substrates and enzymes
D)inhibitors

Question 65

When the end product of a pathway inhibits catalysis of the first step of that pathway,this phenomenon is called

A)reversible covalent modification.
B)feedback inhibition.
C)metabolic channeling.
D)non-competitive inhibition.

Question 66

Enzyme activity can be controlled by

A)allosteric regulation.
B)covalent modification.
C)feedback (end product)inhibition.
D)All of the choices are correct.

Question 67

Based on phosphate transfer potential,which is more likely to happen?

A)Phosphoenolpyruvate will transfer phosphate to ADP
B)ATP will transfer phosphate to phosphoenolpyruvate
C)There will be no phosphate transfer between these molecules

Question 68

In allosteric regulation,effector molecules usually bind

A)reversibly and covalently.
B)irreversibly and covalently.
C)reversibly and noncovalently.
D)irreversibly and noncovalently.

Question 69

What nucleoside trisphosphate,other than ATP,provides some of the energy for protein synthesis?

A)UTP
B)TTP
C)CTP
D)GTP

Question 70

Where is the electron transport chain located in bacterial cells?

A)Plasma membrane
B)Periplasm
C)Mitochondrial inner membrane
D)Mitochondrial outer membrane

Question 71

Consider the following two half reactions: NAD⁺ + H⁺ + 2e^- $\rarr$ NADH E_o (volts)= - 0.32
Pyruvate^- + 2H⁺ + 2e^- $\rarr$ lactate ^2- E_o(volts)= - 0.19
In a redox reaction involving NAD/NADH and pyruvate,_____________ will be the electron donor and ____________ will be the electron acceptor.

A)lactate; pyruvate
B)NADH; pyruvate
C)NAD⁺; pyruvate
D)pyrvuate; lactate

Question 72

The energy made available during cell respiration and fermentation is used to make ______________,which is then available to provide energy for cellular work.

Question 73

Enzymes decrease the overall free energy change in a chemical reaction.

Question 74

What nucleoside trisphosphate provides energy for lipid synthesis?

A)UTP
B)TTP
C)CTP
D)GTP

Question 75

In a branched pathway with many end products,an abundance of one of the end products will usually inhibit

A)the first step in the set of pathways.
B)the first committed step in the branch of the pathway leading to the production of that particular product.
C)the last step before the branch leading to the production of that particular end product.
D)the last step in the production of that particular product.

Question 76

As the difference in reduction potential between a redox pair increases,the amount of free energy made available _______________.

A)decreases
B)increases
C)remains the same
D)cannot be determined

Question 77

Which of the following is a reason for metabolic regulation?

A)Maintain cell components at appropriate levels
B)Conserve materials
C)Ensure efficient use of energy stores
D)All of the choices are correct.

Question 78

In bacterial and archaeal cells,the electron transport chain is located in the _________ whereas in eukaryotic cells,the electron transport chain is located in the ____________.

A)inner mitochondrial membrane; outer mitochondrial membrane
B)plasma membrane; outer mitochondrial membrane
C)inner mitochondrial membrane; plasma membrane
D)plasma membrane; mitochondrial matrix
E)plasma membrane; inner mitochondrial membrane

Question 79

In an ATP molecule,the phosphates are bonded to the adenine ring.

Question 80

Isoenzymes are different enzymes that catalyze the same reaction but can be regulated independently of one another.