AP Biology: Chapter 8 "Introduction to Metabolism"
C
According to the induced fit hypothesis of enzyme catalysis, _____. A) the binding of the substrate depends on the shape of the active site B) some enzymes change their structure when activators bind to the enzyme C) the binding of the substrate changes the shape of the enzyme's active site D) the active site creates a microenvironment ideal for the reaction
C
Allosteric enzyme regulation is usually associated with _____. A) feedback inhibition B) activating activity C) an enzyme with more than one subunit D) the need for cofactors
B
Anabolic pathways ____. A) are usually highly spontaneous chemical reactions B) consume energy to build up polymers from monomers C) release energy as they degrade polymers to monomers D) consume energy to decrease the entropy of the organism and its envirronment
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D
A chemical, transport, or mechanical work is done by an organism, what happens to the heat generated? A) endergonic B) enthalpic C) spontaneous D) exergonic
B
A noncompetitive inhibitor decreases the rate of an enzyme reaction by _____. A) binging at the active site of the enzyme B) changing the shape of the enzyme's active site C) changing the free energy change of the reaction D) acting as a coenzyme for the reaction
C
A number of systems for pumping ions across membranes are powered by ATP. Such ATP-powered pumps are often called ATPases, although they do not often hydrolyze ATP unless they are simultaneously transporting ions. Because small increases in calcium ions in the cytosol can trigger a number of different intracellular reactions, cells keep the cytosolic calcium concentration quite low under normal conditions, using ATP-powered calcium pumps. For example, muscle cells transport calcium from the cytosol into the membranous system called the sarcoplasmic reticulum (SR). If a resting muscle cell's cytosol has a free calcium ion concentration of 10^{-7} while the concentration in the SR is 10^{-2}, then how is the ATPase acting? A) ATPase activity must be powering an inflow of calcium from the outside of the cell into the SR. B) ATPase activity must be transferring Ⓟi to the SR to enable this to occur. C) ATPase activity must be pumping calcium from the cytosol to the SR against the concentration gradient. D) ATPase activity must be opening a channel for the calcium ions to diffuse back into the SR along the concentration gradient.
D
A system at chemical equilibrium ___. A) consumes energy at a steady rate B) releases energy at a steady rate C) has zero kinetic energy D) can do no work
A
Besides turning enzymes on or off, what other means does a cell use to control enzymatic activity? A) localization of enzymes into specific organelles or membranes B) exporting enzymes out of the cell C) connecting enzymes into large aggregates D) hydrophobic interactions
A
Biological evolution of life on Earth, from simple prokaryote-like cells to large, multicellular eukaryotic organisms, ____. A) has occurred in accordance with the laws of thermodynamics B) has caused an increase in the entropy of the planet C) has been made possible by expending Earth's energy resources D) has occurred in accordance with the laws of thermodynamics, by expending Earth's energy resources and causing an increase in the entropy of the planet
B
Choose the pair of terms that correctly completes this sentence: Catabolism is to anabolism as _____ is to _____. A) exergonic; spontaneous B) exergonic; endergonic C) free energy; entropy D) work; energy
B
During a laboratory experiment, you discover that an enzyme-catalyzed reaction has a ∆G of -20 kcal/mol. If you double the amount of enzyme in the reaction, what will be the ∆G for the new reaction? A) -40 kcal/mol B) -20 kcal/mol C) 0 kcal/mol D) +20 kcal/mol
B
For living organisms, which o the following is an important consequence of the first law of thermodynamics? A) The energy content of an organism is constant. B) The organism ultimately must obtain all of the necessary energy for life from its environment. C) The entropy of an organism decreases with time as the organism grows in complexity. D) Organisms grow by converting energy into organic matter.
C
For the enzyme- catalyzed reaction shown in the figure, if the initial reactant concentration is 1.0 micromolar, which of these treatments will cause the greatest increase in the rate of the reaction? A) doubling the activation energy needed B) cooling the reaction by 10 degrees Celsius C) doubling the enzyme concentration D) increasing the concentration of reactants to 10.0 micromolar, while reducing the concentration of enzyme by 1/2
A
How do cells use the ATP cycle shown in the figure? A) Cells use the cycle to recycle ADP and phosphate. B) Cells use the cycle to recycle energy released by ATP hydrolysis. C) Cells use the cycle to recycle ADP, phosphate, and the energy released by ATP hydrolysis. D) Cells use the cycle primarily to generate heat.
C
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? A) Living organisms do not obey the second law of thermodynamics, which states that entropy must increase with time. B) Life obeys the second law of thermodynamics because the decrease in entropy as the organism grows is exactly balanced by an increase in the entropy of the universe. C) As a consequence of growing, organisms cause a greater increase in entropy associated with their growth. D) Living organisms are able to transform energy into entropy.
B
Most cells cannot harness heat to perform work because ___. A) heat is not a form of energy B) temperature is usually uniform throughout a cell C) heat can never be used to do work D) heat must remain constant during work
B
Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's _____. A) entropy B) activation energy C) equilibrium point D) free-energy content
B
The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway is most precisely described as _____. A) metabolic inhibition B) feedback inhibition C) allosteric inhibition D) noncooperative inhibition
D
When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated? A) It is used to power yet more cellular work. B) It is used to store energy as more ATP. C) It is used to generate ADP from nucleotide precursors. D) It is lost to the environment.
A
Which of the following involves a decrease in entropy? A) condensation reactions B) reactions that separate monomers C) depolymerization reactions D) hydrolysis reactions
A
Which of the following is a statement of the first law of thermodynamics? A) Energy cannot be created or destroyed. B) The entropy of the universe is decreasing. C) The entropy of the universe is constant. D) Energy cannot be transferred or transformed.
C
Which of the following is most similar in structure to ATP? A) a pentose sugar B) a DNA nucleotide C) an RNA nucleotide D) an amino acid with three phosphate groups attached
C
Which of the following is the most correct interpretation of the figure? A) Energy from catabolism can be used directly for performing cellular work. B) ADP + Ⓟi are a set of molecules that store energy for catabolism. C) ATP is a molecule that acts as an intermediary to store energy for cellular work. D) Ⓟi acts as a shuttle molecule to move energy from ATP to ADP.
B
Which of the following is true for all exergonic reactions? A) The products have more total energy than the reactants. B) The reaction proceeds with a net release of free energy. C) The reaction goes only in a forward direction: all reactants will be converted to products will be converted to products, but no products will be converted to reactants. D) A net input of energy from the surroundings is required for the reactions to proceed.
C
Which of the following is true of enzymes? A) Enzyme function is increased if the 3-D structure or conformation of an enzyme is altered. B) Enzyme function is independent of physical and chemical environmental factors such as pH and temperature. C) The entropy of an organism decreases with time as the organism grows in complexity. D) Enzymes increase the rate of chemical reaction by providing activation energy to the substrate.
C
Which of the following is true of metabolism in its entirety in all organisms? A) Metabolism depends on a constant supply of energy from food. B) Metabolism uses all of an organism's resources. C) Metabolism consists of all the energy transformation reactions in an organism. D) Metabolism manages the increase of entropy in an organism.
C
Which of the following statements is a logical consequence of the second law of thermodynamics? A) If the entropy of a system increases, there must be a corresponding decrease in the entropy of the universe. B) If there is an increase in the energy of a system, there must be a corresponding decrease in the energy of the rest of the universe. C) Every chemical reaction must increase the total entropy of the universe. D) Energy can be transferred or transformed,but it cannot be created or destroyed.
C
Which of the following statements is representative of the second law of thermodynamics? A) Conversion of energy from one form to another is always accompanied by some gain of free energy. B) Without an input of energy, organisms would tend toward decreasing entropy. C) Cells require a constant input of energy to maintain their high level of organization. D) Every energy transformation by a cell decreases the entropy of the universe.
A
Which term most precisely describes the cellular process of breaking down large molecules into smaller ones? A) catabolism (catabolic pathways) B) metabolism C) anabolism (anabolic pathways) D) dehydration
B
Why is ATP an important molecule in metabolism? A) Its hydrolysis provides an input of free energy for exergonic reactions. B) Its provides energy coupling between exergonic and endergonic reactions. C) Its terminal phosphate group contains a strong covalent bond that, when hydrolyzed, releases free energy. D) Its terminal phosphate bond has higher energy than the other two phosphate bond.
