Chapter 14 - Key Concepts & Review Points

Question 1

Different organisms use different strategies for capturing free energy from their environment and can be classified by their requirement for ____________.

Answer 1

oxygen

Question 2

Mammalian nutrition involves the intake of macronutrients (____________, ____________, and ____________) and micronutrients (____________ and ____________).

Answer 2

proteins
carbohydrates
lipids
vitamins
minerals

Question 3

A(n) ____________ is a series of enzyme-catalyzed reactions, often located in a specific part of the cell.

Answer 3

metabolic pathway

Question 4

The flux of material through a metabolic pathway varies with the activities of the enzymes that catalyze ____________.

Answer 4

irreversible reactions

Question 5

These flux-controlling enzymes are regulated by ____________, ____________, ____________, and ____________.

Answer 5

allosteric mechanisms
covalent modification
substrate cycling
changes in gene expression

Question 6

Organisms capture the free energy released on degradation of nutrients as “high-energy” compounds such as ________, whose subsequent breakdown is used to power otherwise endergonic reactions.

Answer 6

ATP

Question 7

ATP hydrolysis can be coupled to a(n) ____________ such that the net reaction is favorable.

Answer 7

endergonic reaction

Question 8

Phosphoryl groups are transferred from compounds with ________ phosphoryl group-transfer potentials to those with ________ phosphoryl group-transfer potentials.

Answer 8

high

low

Question 9

The ____________ in acetyl-CoA is a “high energy” bond.

Answer 9

thioester bond

Question 10

The electron carriers NAD+ and FAD accept electrons from ____________ and transfer them to other compounds.

Answer 10

reduced metabolites

Question 11

The Nernst Equation describes the thermodynamics of ____________.

Answer 11

oxidation-reduction reactions

Question 12

The reduction potential describes the tendency for an oxidized compound to ________ electrons (become reduced).

Answer 12

gain

Question 13

Free energy and reduction potential are related: the greater the reduction potential, the ____________ the free energy and the more favorable the reaction.

Answer 13

more negative

Question 14

The free energy released from catabolic oxidation reactions is used to drive ____________ reactions.

Answer 14

endergonic anabolic

Question 15

____________ is the intake and utilization of food to supply free energy and raw materials.

Answer 15

nutrition

Question 16

____________ organisms obtain their free energy from compounds synthesized by chemolithotrophic or photoautotrophic organisims.

Answer 16

heterotrophic

Question 17

Near-equilibrium reactions are ____________, whereas reactions that function far from equilibrium serve as regulatory points and render metabolic pathways ____________.

Answer 17

reversible

irreversible

Question 18

Flux through a metabolic pathway is controlled by regulating the activities of the enzymes that catalyze its ____________.

Answer 18

rate-determining steps

Question 19

The free energy of the “high-energy” compound ATP is made available through cleavage of one or more of its ____________.

Answer 19

phosphoanhydride bonds

Question 20

A(n) ____________ reaction such as ATP or PPi hydrolysis can be coupled to a(n) ____________ reaction to make it more favorable.

Answer 20

exergonic

endergonic

Question 21

Substrate-level phosphorylation is the synthesis of _________ from ________ by phosphoryl group transfer from another compound.

Answer 21

ATP

ADP

Question 22

The common product of carbohydrate, lipid, and protein catabolism is ____________, a “high-energy” thioester.

Answer 22

acetyl-CoA

Question 23

The coenzymes ________ and ________ are reversibly reduced during the oxidation of metabolites.

Answer 23

NAD+

FAD

Question 24

The Nernst Equation relates the _____________ of a redox reaction to the ____________ and ____________ of the electron donors and acceptors.

Answer 24

electromotive force
standard reduction potentials
concentrations

Question 25

Electrons flow spontaneously from the ____________ member of a redox couple with the more ____________ reduction potential to the ____________ member of the redox couple with the more ____________ reduction potential.

Answer 25

reduced
negative
oxidized
positive