Chapter 9

Question 1

metabolism

Answer 1

all the chemical reactions occurring in a living cell or organism

Question 2

phosphorylation

Answer 2

the addition of a phosphate group to a molecule

Question 3

energetic coupling

Answer 3

in cellular metabolism, the mechanism by which energy released from an exergonic reaction is used to drive an endergonic reaction

Question 4

reduction-oxidation reactions

Answer 4

any chemical reaction that involves the transfer of one or more electrons from one reactant to another

Question 5

electron donor

Answer 5

a reactant that loses an electron and is oxidizedduring a redox reaction

Question 6

cytochrome c

Answer 6

a soluble iron-containing protein that shuttles electrons between membrane bound complexes in the mitochondrial electron transport chain

Question 7

electron acceptor

Answer 7

a reactant that gains an electron and is reduced in a redox reaction

Question 8

nicotinamide adenine dinucleotide

Answer 8

oxidized and reduced forms are NAD+ and NADH, a nonprotein electron carrier that is reduced during the light dependent reactions in photosynthesis and extensively used in biosynthetic reactions

Question 9

electron carrier

Answer 9

any molecule that readily accepts electrons from and donates electrons to other molecules

Question 10

substrate-level phosphorylation

Answer 10

production of ATP by transfer of a phosphate group from an intermediate substrate directly to ADP. Occurs in glycolysis and citric acid cycle

Question 11

phosphofructokinase

Answer 11

the enzyme that catalyzes synthesis of fructose -1, 6-bisphosphate from from fructose 6-phosphate, a key step in glycolysis

Question 12

feedback inhibition

Answer 12

a type of metabolic control in which high concentrations of the product of a metabolic pathway inhibit one of the enzymes early in the pathway

Question 13

regulatory site

Answer 13

a site on an enzyme to which a regulatory molecule can bind and affect the enzymes activity, separate from the active site where catalysis occurs

Question 14

coenzyme A

Answer 14

a nonprotein molecule that is required for many cellular reactions involving the transfer of acetyl groups

Question 15

acetyl CoA

Answer 15

a molecule produced by the oxidation of a pyruvate catalyzed by pyruvate dehydrogenase, can enter the citric acid cycle and is also used as a carbon source in the synthesis of fatty acids, steroids and other compounds

Question 16

lactic acid fermentation

Answer 16

catabolic pathway in which pyruvate produced by glycolysis is converted into lactic acid in the absence of oxygen

Question 17

alcohol fermentation

Answer 17

catabolic pathway in which pyruvate produced by glycolysis is converted to ethanol in the absence of oxygen

Question 18

carboxylic acids

Answer 18

organic acids with the form of R-COOH(carboxyl group)

Question 19

citric acid cycle

Answer 19

a series of eight chemical reactions that starts with citrate and ends with oxaloacetate which reacts with acetyl CoA to form citrate- forming a cycle that is part of the pathway that oxidizes glucose into CO2

Question 20

guanosine triphosphate

Answer 20

a molecule consisting of guanine, a sugar and three phosphate groups. can be hydrolyzed to release free energy and commonly used in many cellular reactions

Question 21

ubiquinone

Answer 21

a nonprotein molecule that shuttles electrons between membrane bound complexes in the mitochondrial electron transport chain also called coenzyme Q

Question 22

proton-motive force

Answer 22

the combined effect of a proton gradient and an electric potential gradient across a membrane, which can drive protons across the membrane. used by mitochondria and chloroplast to power ATP synthesis

Question 23

chemiosmosis

Answer 23

an energetic coupling mechanism whereby energy stored in an electrochemical proton gradient is used to drive an energy requiring process such as the production of ATP

Question 24

facultative anaerobes

Answer 24

any organism that can perform aerobic respiration when oxygen is available to serve as an electron acceptor but can switch to fermentation when there is not

Question 25

catabolic pathways

Answer 25

any set of chemical reactions that breaks down larger. more complex molecules into smaller ones, releasing energy in the process

Question 26

anabolic pathways

Answer 26

any set of chemical reactions that synthesize larger molecules from smaller ones, generally requires energy