Deck 5: Bioenergetics: the Flow of Energy in the Cell

Question 1

Bioluminescence can be driven by

A)green fluorescent protein.
B)ATP.
C)chemical oxidation.
D)either ATP or chemical oxidation.
E)mushrooms.

Answer 1

D

Question 2

Which of the following types of work involves a change in position of the cell or a cell structure?

A)bioluminescent
B)electrical
C)mechanical
D)synthetic
E)concentration

Answer 2

C

Question 3

In a chemical reaction,the standard free energy change (ΔG°')is calculated to be 3.67 cal/mol.What can be said of the chemical reaction?

A)The reaction is at equilibrium under standard conditions.
B)The reaction goes spontaneously to the right under standard conditions.
C)The reaction is not spontaneous under standard conditions.
D)Products predominate over reactants at equilibrium under standard conditions.
E)There can be no reaction.

Answer 3

C

Question 4

Which of the following is defined as "heat content"?

A)energy output
B)heat loss
C)entropy
D)solar radiation
E)enthalpy

Question 5

Which of the following is a chemoheterotroph?

A)grass
B)a tree
C)a mushroom
D)a photosynthetic bacterium
E)algae

Question 6

Bioenergetics can be simply defined as

A)a subdivision of biology.
B)applied thermodynamics.
C)the units in which energy is expressed.
D)the application of biological principles to physics.
E)holding constant the variables in the universe.

Question 7

In a chemical reaction,the standard free energy change (ΔG°')is calculated to be −3.67 cal/mol.What can be said of the chemical reaction?

A)The reaction is at equilibrium under standard conditions.
B)The reaction is spontaneous under standard conditions.
C)The reaction is not spontaneous under standard conditions.
D)Reactants predominate over products at equilibrium under standard conditions.
E)There can be no reaction.

Question 8

In a chemical reaction at equilibrium,the concentration of R (the reactant)is 3.0 mol/L and the concentration of P (the product)is 0.9 mol/L.At 25°C,what would be the K_eq?

A)1.5
B)0.3
C)1.0
D)3.0
E)37.5

Question 9

Which of the following is a phototroph?

A)a tree
B)a mushroom
C)soil bacterium
D)an earthworm
E)a person

Question 10

A negative free energy change indicates that

A)the reaction is not possible.
B)energy must be added to the reaction before it can proceed.
C)the reactant is predominant at equilibrium.
D)the reaction is exothermic.
E)the reaction is at equilibrium.

Question 11

In a reversible chemical reaction at equilibrium,the concentration of X (the reactant)is 0.75 mol/L,and the concentration of Y (the product)is 2.25 mol/L.At 25°C,what would be the K_eq?

A)0.33
B)3.0
C)1.69
D)1.50
E)37.5

Question 12

Muscle contraction is an example of which of the following types of work?

A)heat
B)mechanical
C)bioluminescent
D)electrical
E)concentration

Question 13

"The total amount of mass-energy in the universe is constant," is a statement of

A)the first law of thermodynamics.
B)the second law of thermodynamics.
C)thermodynamic spontaneity.
D)entropy.
E)enthalpy.

Question 14

A spontaneous reaction

A)has to occur immediately.
B)will never occur.
C)has an overall positive free energy change.
D)could occur but might take a very long time.
E)is associated exclusively with homeothermic organisms.

Question 15

When the ΔG°' of a chemical reaction is positive (K'_eq < 1.0)under standard conditions,

A)reactants and products are at equilibrium.
B)work can be done under these conditions.
C)reactants predominate over products.
D)the reaction is spontaneous to the right.
E)the reaction is exothermic.

Question 16

Fireflies have the ability to convert the energy in ATP to light.Which of the following types of work is performed by the firefly?

A)bioluminescent
B)heat
C)concentration
D)electrical
E)mechanical

Question 17

Nerve impulses travel along neurons by the opening of channels that allow sodium ions to flow inward,followed by an outward flow of potassium ions.In order to ensure that the impulse may be produced at any time,sodium is actively transported out of the cell and potassium is transported into the cell by the sodium/potassium pump.Which of the following types of work is performed by the sodium/potassium pump?

A)mechanical
B)electrical
C)concentration
D)synthetic
E)bioluminescent

Question 18

Which of the following is not a basic need of the cell?

A)molecular building blocks
B)100% efficiency
C)energy
D)information
E)chemical catalysts

Question 19

Animals that regulate their body temperature independently of the environment are called

A)heterotherms.
B)homeotherms.
C)poikilotherms.
D)biotherms.
E)abiotherms.

Question 20

Which of the following is an endothermic process?

A)combustion reactions
B)adding a strong acid directly to water
C)oxidation of metals
D)ice melting
E)neutralization reactions of the addition of strong acid directly to a strong base

Question 21

Photosynthesis is an important process that

A)is performed by heterotrophs.
B)produces oxidized products.
C)uses water and carbon dioxide as reactants.
D)is performed by organisms living near deep-ocean thermal vents.
E)only plants can perform.

Question 22

Which is true of heterotrophs?

A)They capture light energy.
B)They cannot be unicellular.
C)They store energy in the form of heat.
D)They can function as autotrophs in an emergency.
E)They can obtain energy by consuming phototrophs.

Question 23

When ΔG' = 0 in a chemical reaction,under standard conditions,

A)reactants and products are at equilibrium.
B)work can be done; energy is required.
C)the reaction is spontaneous to the left.
D)no work can be done; no energy is required.
E)reactants and products are at equilibrium; no work can be done; no energy required.

Question 24

Matter and energy flow through the biosphere.The flow of matter,however,differs from the flow of energy.Which of the following statements accurately describes these differences?

A)Matter flows in cycles,whereas energy flows in one direction.
B)Matter does not accompany energy as it enters the biosphere,but it does flow with energy from the biosphere.
C)Energy flows from chemotrophs to phototrophs,whereas matter flows from phototrophs to chemotrophs.
D)Energy flows as organic molecules are reduced to inorganic molecules,but matter does not.
E)Matter and energy flow sometimes in cycles and sometimes unidirectionally.

Question 25

In a cell,the concentration of glucose-6-phosphate is 83 ?M and of fructose-6-phosphate is 14 ?M.The ?G°' = 410 cal/mol for the conversion of glucose-6-phosphate to fructose-6-phosphate.Based upon this information,the ?G' for this reaction (in cal/mol)is

A)?644.
B)?63.7.
C)0.
D)27.
E)644.

Question 26

In a biochemical reaction,reactants may be converted into products.The extent to which this occurs spontaneously is expressed as which of the following?

A)ΔG
B)K_eq
C)ΔS
D)temperature
E)TΔS

Question 27

What form of energy do all living organisms use?

A)sunlight
B)radiation
C)chemical bonds
D)nuclear energy
E)heat

Question 28

The flow of energy in the biosphere begins primarily with

A)chemotrophs.
B)phototrophs.
C)lightning.
D)oxidized chemicals.
E)high-energy electrons.

Question 29

A student drops his notes,and his papers scatter.The fact that the papers scatter and do not remain neatly stacked is an illustration of

A)the first law of thermodynamics.
B)the second law of thermodynamics.
C)an increase in entropy.
D)both the first and second laws of thermodynamics.
E)an increase in entropy as predicted by the second law of thermodynamics.

Question 30

Which of the following statements is false concerning the value ΔH?

A)ΔH is the change in heat content.
B)ΔH is the change in enthalpy.
C)In biology,ΔH is basically the same as ΔE.
D)A reaction with a positive ΔH value is exothermic.
E)ΔH = ΔE + Δ(PV)

Question 31

Reduction involves the

A)loss of neutrons.
B)gain of electrons.
C)increase in oxidation state.
D)gain of electrons and an increase in oxidation state.
E)loss of neutrons,gain of electrons,and an increase in oxidation state.

Question 32

The steady state vital to life is possible because

A)the cell cannot convert energy from one form to another.
B)all cells are autotrophic.
C)the cell continually takes up energy from the environment.
D)all reactions are at equilibrium.
E)all reactions are exothermic.

Question 33

Which of the following statements are false concerning phototrophs?

A)They capture light energy.
B)They can be bacteria.
C)They store energy as glucose.
D)They are not autotrophs.
E)They provide energy for chemotrophs.

Question 34

Which process involves an increase in entropy of the system?

A)freezing of ice
B)any spontaneous process
C)combustion of paper
D)formation of raindrops
E)synthesis of cellulose

Question 35

Energy is important to life forms because

A)all life forms require a continuous supply of energy.
B)energy is required to do work.
C)energy is required to make specific alterations in the cell.
D)all life forms require a continuous supply of energy and energy is required to do work.
E)all life forms require a continuous supply of energy,energy is required to do work,and energy is required to make specific alterations in the cell.

Question 36

Under the conditions of a given reaction,a positive ΔG' means

A)the reaction is spontaneous.
B)no energy needs to be added.
C)the reaction is at equilibrium.
D)work can be done.
E)the reaction will not occur.

Question 37

Energy-requiring reactions can occur in biological systems because they can be coupled with reactions that are

A)unlikely.
B)not spontaneous.
C)endergonic.
D)exergonic.
E)spontaneous and endergonic.

Question 38

Oxidation

A)involves the removal of oxygen atoms from a molecule.
B)is endothermic.
C)occurs when an atom accepts electrons.
D)occurs when oxygen atoms are added to a molecule and energy released.
E)is rare in biological reactions.

Question 39

Life is possible because living cells maintain themselves in a steady state,with most of their reactions

A)far from thermodynamic equilibrium.
B)near thermodynamic equilibrium.
C)conserving energy.
D)conserving matter.
E)conserving energy and matter.

Question 40

The statement,"Energy is neither created nor destroyed," is a statement of

A)the first law of thermodynamics.
B)the second law of thermodynamics.
C)entropy.
D)enthalpy.
E)an early theory of energy that has now been proven false.

Question 41

What is a Calorie and why is the caloric content of food displayed on nutrition labels? Which contains more energy,1 gram of fat or 1 gram of sugar? Why?

Question 42

The equilibrium constant (K'_eq)for the reaction,glucose-6-phosphate + water → glucose + phosphate,is 260.What is the ΔG°' for this reaction? What do the values of K'_eq and ΔG°' tell you about this reaction?

Question 43

Compare how energy and matter flow in an ecosystem and relate this flow to the laws of thermodynamics and matter conservation.

Question 44

Within biological systems,there are always reactions that seem to occur when thermodynamically they should not.An example is in the process of glycolysis,ΔG°' = 2183.6 kJ/mol.How is this possible,when cells are governed by the laws of thermodynamics?