Mastering Biology: Ch. 8

as ATP begins to build up in a cell, metabolism slows down. how does this happen

ATP acts as an allosteric inhibitor to many of the enzymes involved in metabolism, causing them to stop functioning

cells use ATP constantly, but ATP is considered a renewable source. what process makes this possible?

ATP can be regenerated by the addition of a phosphate group to ADP

the primary manner in which cells manage their energy resources in order to do work is called energy coupling. which of the following statements accurately defines energy coupling

EXERgonic reactions drive ENDERgonic reactions

if the entropy of a living organism is decreasing, which of the following is most likely to be occurring simultaneously?

Energy input into the organism must be occurring to drive the decrease in entropy.

which of the following statements is correct regarding KE and PE

KE is the energy associated w/ the relative motion of objects PE is the energy that matter possesses because of its location/structure

which of the following states the relationship between anabolic and catabolic pathways energy derived from catabolic pathways is used to drive the breakdown of organic molecules in anabolic pathways catabolic pathways produce stable usable cellular energy by synthesizing more complex organic molecules degradation of organic molecules by anabolic pathways provides the energy to drive catabolic pathways anabolic pathways synthesize more complex organic molecules using the energy derived from catabolic pathways the flow of energy between catabolic and anabolic pathways is reversible

anabolic pathways synthesize more complex molecules using the energy derived from catabolic pathways

at low T, a particular enzyme catalyzes a reaction, but at a slow rate. at high T, the enzyme is completely inactive. what statement best explains the difference in how T affects the function of this enzyme?

at low T, there is not enough free energy for the enzyme to function at a high rate, and at high T the enzyme is denatured, leaving it nonfunctional

which of the following statements correctly describes cofactors and coenzymes

both are nonprotein enzyme helpers; but most cofactors are metal ions and coenzymes are organic molecules that are a specific type of cofactor

how does ATP drive mechanical work inside a cell

by binding to motor proteins

how does ATP drive transport work inside a cell

by phsophorylating a transport protein

which of the following statements is correct regarding competitive and noncompetitive enzyme inhibitors

competitive inhibitors bind to the active site of an enzyme while noncompetitive inhibitors bind to an enzyme away from the active site

which of the following states the relevance of the first law of thermodynamics to biology? living organisms must increase the entropy of their surroundings energy is destroyed as glucose is broken down during cellular respiration energy can be freely transformed among different forms as long as the total energy is conserved the total energy taken in by an organism must be greater than the total energy stored or released by the organism photosynthetic organisms produce energy in sugars from sunlight

energy can be freely transformed among different forms as long as the total energy is conserved

if the entropy of a living organism is decreasing, which of the following is most likely to be occurring simultaneously

energy input into the organism must be occurring to drive the decrease in entropy

which of the following statements about enzyme function is correct

enzymes can lower the activation energy of reactions, but they cannot change the equilibrium point because they cannot change the net energy output

which of the following statements about enzymes is true

enzymes speed up the rate of the reaction without changing the delta G for the reaction enzymes do NOT function faster is MORE heat is added

ATP allosterically inhibits enzymes in ATP-producing pathways. the result of this is called

feedback inhibition

which of the following reactions would be endergonic glucose + fructorse --> sucrose ATP --> ADP + Pi glucose + 6O2 --> 6CO2 + 6H20 HCl --> H + Cl

glucose + fructose --> sucrose

enzyme activity is affected by pH because ____________

high or low pH may disrupt hydrogen bonding or ionic interactions, and thus change the shape of the active site

which of the following is true regarding metabolic pathways? metabolic pathways are not important to a cell's ability to function each reaction in the pathway is catalyzed by the same enzyme metabolic pathways consist of only anabolic pathways metabolic pathways consists of a series of reactions, each catalyzed by a dif. enzyme metabolic pathways consist of a single chemical reaction

metabolic pathways consist of a series of reactions, each catalyzed by a different enzyme

What would the value of ΔS be for a chemical reaction in which a molecule is broken down into smaller components?

positive

an exergonic (spontaneous) reaction is a chemical reaction that:

releases energy when proceeding in the forward direction

an exergonic reaction _________ free energy, and an edergonic reaction ___________ free energy

releases, absorbs

in general, hydrolysis of ATP drives cellular work by:

releasing free energy that can be coupled to other reactions

which of the following is changed by the presence of an enzyme in a reaction? the activation energy the G value for the products the sign of delta G the G value for the reactants the magnitude of delta G

the activation energy G is NOT affected in any way

which of the following statements about the active site of an enzyme is correct? the active site has a fixed structure the active site may resemble a groove or pocket in the surface of a protein into which the substrate fits the active site allows the reaction to occur under the same env. conditions as the reaction without the enzyme the structure of the active site is not affected by changes in temperature coenzymes are rarely found in the active site of an enzyme

the active site may resemble a groove or pocket in the surface of a protein into which the substrate fits

which of the following is an example of the second law of thermodynamics? cellular respiration releases some energy as heat all types of cellular respiration produce ATP the aerobic respiration of one molecule of glucose produces six molecules of carbon dioxide and water

the aerobic respiration of one molecule of glucose produces six molecules of carbon dioxide and water

which of the following statements is correct regarding ATP the energy in an ATP molecule is released from the adenine group the energy in an ATP molecule is released from the ribose group ATP cannot transfer energy to other molecules the energy in an ATP molecule is released through hydrolysis of one of the phosphate groups ATP molecules do not release free energy when hydrolyzed

the energy in an ATP molecule is released through hydrolysis of one of the phosphate groups

at low pH, a particular enzyme catalyzes a reaction at a high rate. at neutral pH, the enzyme is completely inactive. what statement best explains the difference in how pH affects the function of this enzyme

the enzyme is adapted for low pH but is denatured at neutral pH, leaving it NONfunctional

what best characterizes the role of ATP in cellular metabolism?

the free energy released by ATP hydrolysis that may be coupled to an endergonic process via the formation of a phosphorylated intermediate