AP Biology: Chapter 8 Test

b

A chemical reaction that has a positive deltaG is best described as ________. A) enthalpic B) endergonic C) spontaneous D) exergonic

b

A noncompetitive inhibitor decreases the rate of an enzyme reaction by ______. A) binding 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

d

A system at chemical equilibrium _________. A) releases energy at a steady rate. B) consumes energy at a steady C) has zero kinetic energy D) can do no work

c

Choose the pair of terms that correctly completes this sentence: Catabolism is to anabolism as _________ is to _________. A) exergonic; spontaneous B) work; energy C) exergonic; endergonic D) free energy; entropy

b

During a laboratory experiment, you discover that an enzyme-catalyzed reaction has a deltaG of -20 kcal/mol. If you double the amount of enzyme in the reaction, what will be the deltaG for the new reaction? A) -40 kcal/mol B) -20 kcal/mol C) 0 kcal/mol D) +20 kcal/mol

activation energy

In energy-catalyzed reactions, enzymes lower ________ _______.

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 mathematical expression for the change in free energy of a system is deltaG=deltaH-TdeltaS. Which of the following is (are) correct? A) deltaS is the change in enthalpy, a measure of randomness. B) deltaG is the change in free energy. C) T is the temperature in degrees Celsius. D) deltaH is the change in entropy, the energy available to do work.

c

When ATP releases some energy, it also releases inorganic phosphate. What happens to the inorganic phosphate in the cell? A) It is secreted as waste. B) It is used only to regenerate more ATP. C) It may be used to form a phosphorylated intermediate. D) It enters the nucleus and affects gene expression.

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 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 the most correct interpretation of the figure? A) Energy from catabolism can be used directly for performing cellular work. B) ADP + Pi are a set of molecules that store energy for catabolism. C) ATP is amolecule that acts as an intermediary to store energy for cellular work. D) Pi acts as a shuttle molecule to move energy from ATP to ADP.

c

Which of the following is true for all exergonic reactions? A) The products have more total energy than the reactants. B) The reaction goes only in a forward direction: all reactants will be converted to products, but no products will be converted to reactants. C) The reaction proceeds with a net release of free energy. D) A net input of energy from the surrounding 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) Enzymes increase the rate of chemical reaction by lowering activation energy barriers. 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 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.

d

Which of the following types of reactions would decrease the entropy within a cell? A) anabolic reactions B) hydrolysis C) digestion D) catabolic reactions

a

Which term most precisely describes the cellular process if 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) It provides energy coupling between exergonic and endergonic reactions. C) Its terminal phosphate group contains a strong covalent bond that, when hydrolyzed, releases free energy.

deltaG

_______ is independent of the activation energy and enzyme.

enzymes

__________ do not provide energy other than collision energy.

noncompetitive inhibitors

___________ _______________ attach to sites other than the active site and change the shape of the active site.