Chapter 6: An Introduction To Metabolism
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- 1.Which of the following situations does NOT represent a transformation of one type of energy to another?
- A.
The burning of gasoline in a car engine
- B.
The production of sugar by photosynthesis
- C.
The production of electrical power by damming a river
- D.
Cracking a nut by using a nutcracker
- E.
Plugging a stereo into a wall socket to play music
- 2.What is energy?
- A.
The capacity to perform work
- B.
The amount of food eaten
- C.
Movement
- D.
The rearrangement of chemical molecules within matter
- E.
The capacity to produce heat
- 3.Energy is most commonly stored in plants as ____________.
- A.
Electrical energy
- B.
Mechanical energy
- C.
Electromagnetic energy
- D.
Kinetic energy
- E.
Chemical energy
- 4.Organisms are described as thermodynamically open systems. This means that _____.
- A.
The metabolism of an organism is isolated from its surroundings
- B.
Organisms can reverse the increase in entropy
- C.
Organisms acquire energy from their surroundings
- D.
Organisms are capable of circumventing the second law of thermodynamics
- E.
Because energy is conserved, organisms do not require energy input from their surroundings
- 5.
- A.
Energy conversions increase the order in the universe.
- B.
The total amount of energy in the universe is constant.
- C.
The ordering of one system depends on the disordering of another.
- D.
The entropy of the universe is constantly decreasing.
- E.
All reactions produce some heat.
- 6.Which one of the following is an example of the second law of thermodynamics?
- A.
The aerobic respiration of glucose generates heat.
- B.
All types of cellular respiration produce ATP.
- C.
CO2 is exhaled as a by-product of aerobic respiration.
- D.
Photosynthesis enables plants to create energy from sunlight.
- E.
Energy is stored during the Calvin cycle.
- 7.If the entropy of a system is increasing, this means that ____________.
- A.
The sun's energy is being captured by photosynthesis
- B.
Heat is being used by organisms as a source of energy
- C.
The first law of thermodynamics is being violated
- D.
Energy input will be needed to maintain organization
- E.
The amount of usable energy in the system is increasing
- 8.The first law of thermodynamics ____________.
- A.
Deals with entropy
- B.
States that energy is neither created nor destroyed
- C.
Deals with heat content
- D.
States that entropy spontaneously increases
- E.
Predicts the direction of a reaction
- 9.Which one of the following is NOT true about the second law of thermodynamics?
- A.
It states that energy is neither created nor destroyed.
- B.
It deals with entropy.
- C.
It deals with heat content.
- D.
It deals with spontaneity.
- E.
All the above are true.
- 10.Which one of the following has the most free energy per molecule?
- A.
A sugar molecule
- B.
An amino acid molecule
- C.
A starch molecule
- D.
A fatty acid molecule
- E.
A cholesterol molecule
- 11.From the equation DG = DH - TDS it is clear that _____.
- A.
A decrease in the system's total energy will increase the probability of spontaneous change
- B.
Increasing the entropy of a system will increase the probability of spontaneous change
- C.
Increasing the temperature of a system will increase the probability of spontaneous change
- D.
The capacity of a system to perform work is related to the total energy of the system
- E.
All of the above are true
- 12.What must be true if the reaction AB + CD —> AC + BD occurs spontaneously?
- A.
The DG of the reaction must be negative.
- B.
The reaction must be exergonic.
- C.
The environment has adequate thermal energy to meet the activation energy requirement.
- D.
The bonds must have absorbed enough energy to become unstable.
- E.
All of the above are true.
- 13.Which of the following reactions would be endergonic?
- A.
HCl —> H+ + Cl-
- B.
C6H12O6 + 6 O2 —> 6 CO2 + 6 H2O
- C.
ATP —> ADP + Pi
- D.
Maltose + fructose —> sucrose
- E.
All of the above
- 14.Which one of the following tells us, without additional information, the way a process will go spontaneously?
- A.
DG
- B.
DH
- C.
DS
- D.
TDS
- E.
All of these values tell us the direction in which a reaction will go.
- 15.If, during a process, the system becomes more ordered, then ____________.
- A.
DG is negative
- B.
DG is positive
- C.
DH is negative
- D.
DH is positive
- E.
TDS is negative
- 16.An exergonic (spontaneous) reaction is a chemical reaction that ____________.
- A.
Occurs only when an enzyme is present
- B.
Occurs within living cells but not in a test tube
- C.
Releases energy when proceeding in the forward direction
- D.
Occurs in all living cells
- E.
All of the above
- 17.When one molecule is broken down into six component molecules, which one of the following is definitely true?
- A.
Outside energy is needed.
- B.
DG is positive.
- C.
DH is negative
- D.
DS is positive.
- E.
DS is negative
- 18.When DG is positive, the reaction or process can be termed ___________.
- A.
Endergonic
- B.
Exergonic
- C.
Exothermic
- D.
Endothermic
- E.
Enthalpic
- 19.A reaction is designated as exergonic rather than endergonic when ___________.
- A.
Activation energy is necessary
- B.
No kinetic energy is released
- C.
Activation energy exceeds net energy release
- D.
The potential energy of the products is less than the potential energy of the reactants
- E.
It absorbs more energy
- 20.What best characterizes the role of ATP in cellular metabolism?
- A.
The release of free energy during the hydrolysis of ATP heats the surrounding environment.
- B.
Its free energy is coupled to an endergonic process via the formation of a phosphorylated intermediate.
- C.
It is catabolized to carbon dioxide and water.
- D.
The DG associated with its hydrolysis is positive.
- E.
The polar phosphate groups assist in the alignment of polar substrates as they enter an enzyme's active site.
- 21.Much of the suitability of ATP as an energy intermediary is related to the instability of the bonds between the phosphate groups. These bonds are unstable because _____.
- A.
The valence electrons in the phosphorus atom have less energy on average than those of other atoms
- B.
The negatively charged phosphate groups vigorously repel one another
- C.
They are hydrogen bonds, which are only about 10% as strong as covalent bonds
- D.
The phosphate groups are polar and are attracted to the water in the cell's interior
- E.
All of the above
- 22.Which monomer could be most easily modified to form ATP?
- A.
The RNA nucleotide adenosine
- B.
The amino acid tryptophan
- C.
The DNA nucleotide adenosine
- D.
Cholesterol
- E.
The monosaccharide galactose
- 23.___________ is an example of the cellular work accomplished with the free energy of ATP hydrolysis.
- A.
Mechanical work, such as the beating of cilia,
- B.
Transport work, such as the movement of glucose into an adipose cell,
- C.
Chemical work, such as the synthesis of new protein,
- D.
Mechanical work, such as pumping blood through the circulatory system,
- E.
All of the above
- 24.The formation of glucose-6-phosphate from glucose is coupled to the reaction ____________.
- A.
ATP —> ATP + Pi
- B.
ADP —> ATP + Pi
- C.
ATP —> ADP
- D.
ADP —> ATP
- E.
ADP + Pi —> ATP
- 25.In general, the hydrolysis of ATP drives cellular work by _____.
- A.
Changing to ADP and phosphate
- B.
Transferring a phosphate group to some other molecule
- C.
Releasing heat
- D.
Acting as a catalyst
- E.
Lowering the free energy of the reaction
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