Question 1

Bioluminescence can be driven by
A)green fluorescent protein.
B)ATP.
C)chemical oxidation.
D)either ATP or chemical oxidation.
E)mushrooms.

Accepted Answer

Bioluminescence is primarily driven by the chemical oxidation of a light-emitting molecule (luciferin) in the presence of an enzyme (luciferase), which often requires ATP as an energy source. Therefore, it can be driven by either ATP or chemical oxidation.

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

Accepted Answer

Mechanical work in cells involves the physical movement of structures within the cell, such as organelles, chromosomes during cell division, or the cell itself in the case of motile cells. This type of work directly results in a change in position, distinguishing it from other forms of cellular work that involve changes in energy state or molecular composition but not physical location.

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.

Accepted Answer

When the standard free energy change (ΔG°') is positive, as in this case with 3.67 cal/mol, it indicates that the reaction is not spontaneous under standard conditions.

Question 4

Which of the following is defined as "heat content"?
A)energy output
B)heat loss
C)entropy
D)solar radiation
E)enthalpy

Accepted Answer

Enthalpy is defined as the total heat content of a system. It is a thermodynamic quantity equivalent to the total heat content of a system, often used in the study of energy transfer in physical and chemical processes.

Question 5

Which of the following is a chemoheterotroph?
A)grass
B)a tree
C)a mushroom
D)a photosynthetic bacterium
E)algae

Accepted Answer

Mushrooms are chemoheterotrophs because they obtain their energy by consuming organic matter, unlike plants and photosynthetic bacteria that produce their own food through photosynthesis.

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.

Accepted Answer

Bioenergetics is the study of the transformation of energy in living organisms, which is closely related to applied thermodynamics.

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.

Accepted Answer

A negative value for the standard free energy change (ΔG°') indicates that the reaction is spontaneous under standard conditions.

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

Accepted Answer

The equilibrium constant (K_eq) is calculated using the formula K_eq = [P]/[R]. Substituting the given concentrations, K_eq = 0.9/3.0 = 0.3.

Question 9

Which of the following is a phototroph?
A)a tree
B)a mushroom
C)soil bacterium
D)an earthworm
E)a person

Accepted Answer

Trees are phototrophs because they use light energy from the sun to photosynthesize, producing their own food.

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.

Accepted Answer

A negative free energy change indicates that the reaction is exothermic, meaning it releases energy to the surroundings.

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

Accepted Answer

The equilibrium constant (K) for a reversible reaction is given by the ratio of the concentration of the products to the reactants, raised to the power of their stoichiometric coefficients. Assuming a simple reaction where X converts to Y (X ⇌ Y), the equilibrium constant expression would be K = [Y]/[X]. Substituting the given concentrations, K = 2.25 / 0.75 = 3.0.

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

Accepted Answer

Muscle contraction is an example of mechanical work, as it involves the physical movement of parts of the body.

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.

Accepted Answer

The first law of thermodynamics, also known as the law of conservation of energy, states that energy cannot be created or destroyed in an isolated system, which aligns with the statement that the total amount of mass-energy in the universe is constant.

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.

Accepted Answer

A spontaneous reaction does not necessarily have to occur immediately; it means that it could occur without external input of energy, but the rate at which it happens can vary greatly, from almost instantaneously to taking a very long time.

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.

Accepted Answer

When ΔG°' is positive, it indicates that the reaction is not spontaneous under standard conditions, meaning that the reactants are favored over the products. This is because a positive ΔG°' corresponds to a situation where the free energy of the products is higher than that of the reactants, leading to a predominance of reactants.

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

Accepted Answer

Bioluminescent work involves the conversion of chemical energy into light energy, which is exactly what fireflies do when they produce light through the chemical reaction involving ATP in their light-emitting organs.

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

Accepted Answer

The sodium/potassium pump performs concentration work by moving sodium and potassium ions against their concentration gradients, which requires energy. This process increases the concentration of sodium ions outside the cell and potassium ions inside the cell.

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

Accepted Answer

Cells do not require 100% efficiency to function; in fact, no biological process is 100% efficient due to the second law of thermodynamics, which states that every energy transfer or transformation increases the entropy of the universe. Cells do require molecular building blocks for construction and repair, energy for metabolism, information (usually in the form of DNA or RNA) to direct cellular processes, and chemical catalysts (such as enzymes) to speed up chemical reactions.

Question 19

Animals that regulate their body temperature independently of the environment are called
A)heterotherms.
B)homeotherms.
C)poikilotherms.
D)biotherms.
E)abiotherms.

Accepted Answer

Homeotherms are animals that maintain a constant body temperature regardless of the environmental temperature. This term is synonymous with endotherms, which use metabolic processes to generate heat and keep their body temperature stable.

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

Accepted Answer

Ice melting is an endothermic process because it requires the absorption of heat from the surroundings to change from the solid phase to the liquid phase.

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

Bioluminescence can be driven by

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

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?

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

Which of the following is a chemoheterotroph?

Bioenergetics can be simply defined as

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?

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?

Which of the following is a phototroph?

A negative free energy change indicates that

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?

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

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

A spontaneous reaction

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

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

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

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

Which of the following is an endothermic process?