Mastering Biology : Chapter 6
Which of the following is true for anabolic pathways?
They consume energy to build polymers from monomers.
Which of the following statements concerning catabolic pathways is true?
They provide energy that can be used to drive cellular work.
The process of cellular respiration, which converts simple sugars such as glucose into CO2 and water, is an example of
a catabolic pathway
Chemical equilibrium is relatively rare in living cells. Which of the following could be an example of a reaction at chemical equilibrium in a cell?
a chemical reaction in which neither the reactants nor the products are being produced or used in any other active metabolic pathway at that time in the cell
Which of the following is an example of potential rather than kinetic energy?
a molecule of glucose Submit
A catabolic pathway may be which of the following?
a set of reactions that release energy that can be used to drive cellular work
The cellular process of synthesizing large molecules from smaller ones is defined as
anabolism.
For the hydrolysis of ATP to ADP + i, the free-energy change is -7.3 kcal/mol under standard conditions (1 M concentration of both reactants and products). In the cellular environment, however, the free-energy change is about -13 kcal/mol. What can we conclude about the free-energy change for the formation of ATP from ADP and i under cellular conditions?
It is about +13 kcal/mol.
Hydrolysis of ATP releases energy, which results in the production of ADP and inorganic phosphate. What is commonly the ultimate fate of inorganic phosphate produced in the cytosol?
It is combined with ADP to regenerate ATP.
When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated?
It is released to the environment
Hydrolysis of ATP releases energy, which results in the production of ADP and inorganic phosphate. What is commonly the immediate fate of the inorganic phosphate in the cell?
It is used to form a phosphorylated intermediate.
Which of the following statements about feedback regulation of a metabolic pathway is correct?
The final product of a metabolic pathway is usually the compound that regulates the pathway.
For living organisms, which of the following is an important consequence of the first law of thermodynamics?
The organism ultimately must obtain all of the necessary energy for life from its environment.
Which of the following is true for all exergonic reactions?
The reaction proceeds with a net release of free energy.
What is the difference (if any) between the structure of ATP and the structure of the precursor of the A nucleotide in RNA?
There is no difference.
Which of the following statements about equilibrium of chemical reactions is correct?
A reaction that is at equilibrium is not capable of doing any work.
ATP hydrolysis in a test tube releases only about half as much energy as ATP hydrolysis in the cell. Which of the following is the best explanation for this observation?
ATP hydrolysis in a test tube occurs under standard conditions; in the cell, reactant and product concentrations differ from standard conditions.
Which of the following describes the critical role that ATP plays in cellular metabolism?
ATP serves as an energy shuttle in the cell, coupling exergonic and endergonic reactions.
Living organisms increase in complexity as they grow, resulting in a decrease in the entropy of an organism. How does this relate to the second law of thermodynamics?
As a consequence of growing, organisms cause a greater increase in entropy in their environment than the decrease in entropy associated with their growth.
Which of the following statements is representative of the second law of thermodynamics?
Cells require a constant input of energy to maintain their high level of organization
Which of the following is a statement of the first law of thermodynamics?
Energy cannot be created or destroyed.
Which of the following statements is a logical consequence of the second law of thermodynamics?
Every chemical reaction must increase the total entropy of the universe.
Which of the following is true of metabolism in its entirety in all organisms?
Metabolism consists of all the energy transformation reactions in an organism.
Which of the following statements about ATP (adenosine triphosphate) is correct?
The cycling between ATP and ADP + Pi provides an energy coupling between catabolic and anabolic pathways.
Which of the following statements about the combustion of glucose with oxygen to form water and carbon dioxide (C6H12O6 + 6 O2 → 6 CO2 + 6 H2O) is correct?
The entropy of the products is greater than the entropy of the reactants.
A series of enzymes catalyze the reactions illustrated in the following metabolic pathway: X → Y → Z → A. Product A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme. What is substance X?
a substrate
ATP is an example of which of the following?
an RNA nucleotide
A series of enzymes catalyze the reactions illustrated in the following metabolic pathway: X → Y → Z → A. Product A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme. With respect to the enzyme that converts X to Y, substance A functions as
an allosteric inhibitor.
Which of the following types of reactions would decrease the entropy within a cell?
anabolic reactions
A system at chemical equilibrium
can do no work
The cellular process of breaking down large molecules into smaller ones is defined as
catabolism.
Which of the following reactions tend to require an input of energy?
dehydration
A chemical reaction that has a positive ΔG is best described as
endergonic.
Choose the pair of terms that correctly completes this sentence: Catabolism is to anabolism as __________ is to __________.
exergonic; endergonic
Which of the following is an exergonic reaction?
hydrolysis of glycogen to release glucose monomers
Which of the following tend(s) to release energy?
hydrolysis reactions
Energy is observed in two basic forms: potential and kinetic. Which of the following correctly matches these forms with a source of energy?
the covalent bonds of a sugar molecule: potential energy
