BIO 116 Chapter 6 Review

Which term most precisely describes the cellular process of breaking down large molecules into smaller ones? a. Catalysis b. Metabolism c. Anabolism d. Dehydration e. Catabolism

E. Catabolism

A chemical reaction that has a positive △G is correctly described as ____. a. Endergonic b. Endothermic c. Enthalpic d. Spontaneous e. Exothermic

a. Endergonic

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. Kinetic energy is stored energy that results from the specific arrangement of matter e. Energy cannot be transferred or transformed.

a. Energy cannot be created or destroyed.

Which of the following statements is (are) true about enzyme-catalyzed reactions? a. The reaction is faster than the same reaction in the absence of the enzyme. b. The free energy change of the reaction is opposite from the reaction in the absence of the enzyme. c. The reaction always goes in the direction toward chemical equilibrium. d. A and B only e. A, B, and C

a. The reaction is faster than the same reaction in the absence of the enzyme.

Which of the following types of reactions would decrease the entropy within a cell? a. dehydration reactions b. hydrolysis c. respiration d. digestion e. catabolism

a. dehydration reactions.

In the figure below, which of the following bests describes the reaction? a. negative △G, spontaneous b. positive △G, nonspontaneous c. positive △G, exergonic d. negative △G, endergonic e. △G of zero, chemical equilibrium

a. negative △G, spontaneous

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 e.+40 kcal/mol

b. -20 kcal/mol

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. d. Its terminal phosphate bond has higher energy than the other two e. all of the above

b. It provides energy coupling between exergonic and endergonic reactions.

For living organisms, which of 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 are unable to transform energy e. Life does not obey the first law of thermodynamics.

b. 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? a. The products have more total energy than the reactants. b. The reaction proceeds with a net release of free energy. c. Some reactants will be converted to products. d. A net input of energy from the surroundings is required for the reactions to proceed. e. The reactions are nonspontaneous.

b. The reaction proceeds with a net release of free energy.

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. endothermic level d. heat content e. free-energy content

b. activation energy

Which of the following is likely to lead to an increase in the concentration of ATP in a cell? a. an increase in a cell's anabolic activity b. an increase in a cell's catabolic activity c. an increased influx of cofactor molecules d. an increased amino acid concentration e. the cell's increased transport of materials to the environment

b. an increase in a cell's catabolic activity

In the figure below, which of the following represents the activation energy required for the enzyme-catalyzed reaction? a. a b. b c. c d. d e. e

b. b

Which of the following terms best describes the reaction shown in the figure below? a. endergonic b. exergonic c. anabolic d. allosteric e. nonspontaneous

b. exergonic

The active site of an enzyme is the region ___. a. binds allosteric regulators of the enzyme. b. on the enzyme that binds substrate c. binds the products of the catalytic reaction d. is inhibited by the presence of a coenzyme or a cofactor. e. None of the above

b. on the enzyme that binds substrate

Which of the following best describes enthalpy (H)? a. the total kinetic energy of a system b. the heat content of a chemical system c. the system's entropy d. the cell's energy equilibrium e. the condition of a cell that is not able to react

b. the heat content of a chemical system

Which of the following shows the correct changes in thermodynamic properties for a chemical reaction in which amino acids are linked to form a protein? a. +△H, +△S, +△G b. +△H, -△S, -△G c. +△H, -△S, +△G d. -△H, -△S, +△G e. -△H, +△S, +△G

c. +△H, -△S, +△G

Which of the following is (are) true for anabolic pathways? a. They do not depend on enzymes b. They are usually highly spontaneous chemical reactions c. They consume energy to build up polymers from monomers. d. They release energy as they degrade polymers to monomers. e. all of the above

c. They consume energy to build up polymers from monomers.

Sucrose is a disaccharide, composed of the monosaccharides glucose and fructose. The hydrolysis of sucrose by the enzyme sucrase results in ____. a. bringing glucose and fructose together to form sucrose. b. the release of water from sucrose as the bond between glucose and fructose is broken. c. breaking the bond between glucose and fructose and forming new bonds from the atoms of water. d. production of water from the sugar as bonds are broken between the glucose monomers. e. utilization of water as a covalent bond is formed between glucose and fructose to form sucrase.

c. breaking the bond between glucose and fructose and forming new bonds from the atoms of water.

In the figure below, which of the following represents the activation energy required for a noncatalyzed reaction? a. a b. b c. c d. d e. e

c. c

Which of the following represents the △G of the reaction shown below? a. a b. b c. c d. d e. e

c. c

Increasing the substrate concentration in an enzymatic reaction could overcome which of the following? a. denaturization of the enzyme b. allosteric inhibition c. competitive inhibition d. saturation of the enzyme activity e. insufficient cofactors

c. competitive inhibition

What term is used to describe the transfer of free energy from catabolic pathways to anabolic pathways? a. feedback regulation b. bioenergetics c. energy coupling d. entropy e. cooperativity

c. energy coupling

The mathematical expression for the change in free energy of a system is △G =△H-T△S. Which of the following is (are) correct? a. △S is the change in enthalpy, a measure of randomness. b. △H is the change in entropy, the energy available to do work. c. △G is the change in free energy. d. T is the temperature in degrees Celsius.

c. △G is the change in free energy.

How can one increase the rate of a chemical reaction? a. Increase the activation energy needed. b. Cool the reactants. c. Decrease the concentration of the reactants. d. Add a catalyst. e. Increase the entropy of the reactants

d. Add a catalyst.

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 balanced by an increase in the entropy of the universe. c. Living organisms do not follow the laws of thermodynamics. d. As a consequence of growing, organisms create more disorder in their environment than the decrease in entropy associated with their growth. e. Living organisms are able to transform energy into entropy.

d. As a consequence of growing, organisms create more disorder in their environment than the decrease in entropy associated with their growth.

Whenever energy is transformed, there is always an increase in the ____. a. Free energy of the system b. Free energy of the universe c. Entropy of the system d. Entropy of the universe e. enthalpy of the universe.

d. Entropy of the universe

Which of the following is true of enzymes? a. All enzymes require a nonprotein cofactor or ion for catalysis to take speed up more appreciably than if the enzymes act alone. b. Enzyme function is increased when the three-dimensional structure or conformation of an enzyme is altered. c. Enzyme function is independent of physical and chemical environmental factors such as pH and temperature. d. Enzymes increase the rate of chemical reaction by lowering activation energy barriers. e. None of the above

d. Enzymes increase the rate of chemical reaction by lowering activation energy barriers

When ATP releases some energy, it also releases inorganic phosphate. What purpose does this serve (if any) in the cell? a. It is released as an excretory waste. b. It can only be used to regenerate more ATP. c. It can be added to water and excreted as a liquid. d. It can be added to other molecules in order to activate them. e. It can enter the nucleus to affect gene expression.

d. It can be added to other molecules in order to activate them.

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. e. It is transported to specific organs such as the brain.

d. It is lost to the environment.

Using the figure below, which best describes the reaction? a. The amount of free energy initially present in the reactants is indicated by "a." b. The amount of free energy present in the products is indicated by "e." c. The amount of free energy released as a result of the noncatalyzed reaction is indicated by "c." d. The amount of free energy released as a result of the catalyzed reaction is indicated by "d." e. The difference between "b" and "c" is the activation energy added by the presence of the enzyme.

d. The amount of free energy released as a result of the catalyzed reaction is indicated by "d."

According to the induced fit hypothesis of enzyme catalysis, which of the following is correct? 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. A competitive inhibitor can outcompete the substrate for the active site. d. The binding of the substrate changes the shape of the enzyme's active site. e .The active site creates a microenvironment ideal for the reaction.

d. The binding of the substrate changes the shape of the enzyme's active site

Which of the following is an example of potential rather than kinetic energy? a. a girl mowing grass b. water rushing over Niagara Falls c. a firefly using light flashes to attract a mate d. a food molecule made up of energy-rich macromolecules e. an insect foraging for food

d. a food molecule made up of energy-rich macromolecules

Which of the following would be the same in an enzyme-catalyzed or noncatalyzed reaction shown in the figure below? a. a b. b c. c d. d e. e

d. d

What is the change in free energy of a system at chemical equilibrium? a. slightly increasing b. greatly increasing c. slightly decreasing d. greatly decreasing e. no net change

e. no net change