Bio Final- CH. 8 test

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

What is a nonprotein "helper" of an enzyme molecule called? a. accessory enzyme d. functional group b. allosteric group e. enzyme activator c. coenzyme

If an enzyme solution is saturated with substrate, the most effective way to obtain an even faster yield of products is to a. add more of the enzyme. d. add an allosteric inhibitor. b. heat the solution to 90°C. e. add a noncompetitive inhibitor. c. add more substrate.

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.

The first law of thermodynamics states that energy can be neither created nor destroyed. For living organisms, which of the following is an important consequence of the first law? 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.

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 energy transfer requires activation energy from the environment. d. Every chemical reaction must increase the total entropy of the universe. e. Energy can be transferred or transformed, but it cannot be created or destroyed.

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

The active site of an enzyme is the region that a. binds allosteric regulators of the enzyme. b. is involved in the catalytic reaction of the enzyme. c. binds the products of the catalytic reaction. d. both A and B

Which of the following statements correctly describe(s) catabolic pathways? a. They do not depend on enzymes. b. They consume energy to build up polymers from monomers. c. They release energy as they degrade polymers to monomers. d. They lead to the synthesis of catabolic compounds. e. both A and B

Some bacteria are metabolically active in hot springs because a. they are able to maintain a cooler internal temperature. b. high temperatures make catalysis unnecessary. c. their enzymes have high optimal temperatures. d. their enzymes are insensitive to temperature. e. they use molecules other than proteins as their main catalysts.

Which of the following describe(s) some aspect of metabolism? a. synthesis of macromolecules d. A and B only b. breakdown of macromolecules e. A, B, and C c. control of enzyme activity

Which of the following is most similar in structure to ATP? a. an anabolic steroid c. RNA nucleotides b. a DNA helix d. a phospholipid

What type of reaction breaks the bonds that join the phosphate groups in an ATP molecule? a. anabolism d. entropic b. hydrolysis e. dehydration synthesis c. dehydration decomposition

Which of the following statements regarding ATP is (are) correct? a. ATP serves as a main energy shuttle inside cells. b. ATP drives endergonic reactions in the cell by the enzymatic transfer of the phosphate group to specific reactants. c. The regeneration of ATP from ADP and phosphate is an endergonic reaction. d. A and B only e. A, B, and C

Which of the following statements is true regarding enzyme cooperativity? a. A multi-enzyme complex contains all the enzymes of a metabolic pathway. b. A product of a pathway serves as a competitive inhibitor of an early enzyme in the pathway. c. A substrate molecule bound to an active site affects the active site of several subunits. d. Several substrate molecules can be catalyzed by the same enzyme.

In your body, what process converts the chemical energy found in glucose into the chemical energy found in ATP? a. potentiation d. anabolism b. cellular respiration e. redox c. digestion

Which of the following characteristics is not associated with allosteric regulation of an enzyme's activity? a. A mimic of the substrate competes for the active site. b. A naturally occurring molecule stabilizes a catalytically active conformation. c. Regulatory molecules bind to a site remote from the active site. d. Inhibitors and activators may compete with one another. e. The enzyme usually has a quaternary structure.

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

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

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.

A chemical reaction that has a positive G is correctly described as a. endergonic. b. endothermic. c. enthalpic. d. spontaneous. e. exothermic.

Zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as a(n) a. competitive inhibitor of the enzyme. d. cofactor necessary for enzyme activity. b. noncompetitive inhibitor of the enzyme. e. coenzyme derived from a vitamin. c. allosteric activator of the enzyme.

According to the first law of thermodynamics, a. matter can be neither created nor destroyed. b. energy is conserved in all processes. c. all processes increase the order of the universe. d. systems rich in energy are intrinsically stable. e. the universe constantly loses energy because of friction.

How does a non-competitive inhibitor decrease the rate of an enzyme reaction? a. by binding at the active site of the enzyme b. by changing the structure of the enzyme c. by changing the free energy change of the reaction d. by acting as a coenzyme for the reaction e. by decreasing the activation energy of the reaction

Which of the following statements is true concerning catabolic pathways? a. They combine molecules into more energy-rich molecules. b. They are usually coupled with anabolic pathways to which they supply energy in the form of ATP. c. They are endergonic. d. They are spontaneous and do not need enzyme catalysis. e. They build up complex molecules such as protein from simpler compounds.

Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's a. entropy. d. heat content. b. activation energy. e. free-energy content. c. endothermic level.

In the reaction A B + C + heat, a. there is a net input of energy. b. the potential energy of the products is greater than that of the reactant. c. the potential energy of the products is the same as that of the reactant. d. the potential energy of the products is less than that of the reactant.

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.

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

What name is given to the reactants in an enzymatically catalyzed reaction? a. EA b. products c. active sites d. reactors e. substrate

Which of the following statements regarding enzymes is true? a. Enzymes decrease the free energy change of a reaction. b. Enzymes increase the rate of a reaction. c. Enzymes change the direction of chemical reactions. d. Enzymes are permanently altered by the reactions they catalyze. e. Enzymes prevent changes in substrate concentrations.

A solution of starch at room temperature does not readily decompose to form a solution of simple sugars because a. the starch solution has less free energy than the sugar solution. b. the hydrolysis of starch to sugar is endergonic. c. the activation energy barrier for this reaction cannot be surmounted. d. starch cannot be hydrolyzed in the presence of so much water. e. starch hydrolysis is nonspontaneous.

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

ATP generally energizes a cellular process by a. releasing heat upon hydrolysis. b. acting as a catalyst. c. coupling free energy released by ATP hydrolysis to free energy needed by other reactions. d. breaking a high-energy bond. e. binding directly to the substrate(s) of the enzyme.

The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway is known as a. metabolic inhibition. d. noncooperative inhibition. b. feedback inhibition. e. reversible inhibition. c. allosteric inhibition.

An enzyme catalyzes a reaction by a. supplying the energy to speed up a reaction. b. lowering the energy of activation of a reaction. c. lowering the G of a reaction. d. changing the equilibrium of a spontaneous reaction. e. increasing the amount of free energy of a reaction.

Choose the pair of terms that correctly completes this sentence: Catabolism is to anabolism as ____ is to ____. a. exergonic; spontaneous d. work; energy b. exergonic; endergonic e. entropy; enthalpy c. free energy; entropy

Which of the following metabolic processes can occur without a net influx of energy from some other process? a. ADP + Pi ATP + H2O d. amino acids protein b. C6H12O6 + 6 O2 6 CO2 + 6 H2O e. glucose + fructose sucrose c. 6 CO2 + 6 H2O C6H12O6 + 6 O2

Which of the following is not true of enzymes? a. Enzyme catalysis is dependent on the pH and temperature of the reaction environment. b. Enzyme catalysis is dependent on the three-dimensional structure or conformation of the enzyme. c. Enzymes provide activation energy for the reaction they catalyze. d. Enzymes are composed primarily of protein, but they may bind nonprotein cofactors. e. Enzyme activity can be inhibited if the enzyme's allosteric site is bound with a noncompetitive inhibitor.

Which of the following statements about metabolism is incorrect? a. Metabolism is an emergent property of life at the level of organisms. b. Metabolism manages the utilization of materials and energy resources. c. The uptake of water associated with the hydrolysis of biological polymers is part of metabolism. d. Metabolism depends on a constant supply of energy. e. None of these statements about metabolism is incorrect.

Consider the following: Succinate dehydrogenase catalyzes the conversion of succinate to fumarate. The reaction is inhibited by malonic acid, which resembles succinate but cannot be acted upon by succinate dehydrogenase. Increasing the ratio of succinate to malonic acid reduces the inhibitory effect of malonic acid. Which of the following is correct? a. Succinate dehydrogenase is the enzyme, and fumarate is the substrate. b. Succinate dehydrogenase is the enzyme, and malonic acid is the substrate. c. Succinate is the substrate, and fumarate is the product. d. Fumarate is the product, and malonic acid is a noncompetitive inhibitor. e. Malonic acid is the product, and fumarate is a competitive inhibitor.

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 the same as 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

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.