Chapter 9

Front 1

Adenosine Diphosphate

Back 1

A molecule consisting of adenine, a sugar, and two phosphate groups. Addition of a third phosphate group produces ATP.

Front 2

Glucose

Back 2

Six-carbon monosaccharide whose oxidation in cellular respiration is the major source of ATP in animal cells.

Front 3

Metabolism

Back 3

All the chemical reactions occurring in a living cell or organism.

Front 4

Phosphorylation

Back 4

The addition of a phosphate group to a molecule.

Front 5

What happens when ATP is hydrolyzed?

Back 5

A large free energy change of 30.5 kJ/mol ATP occurs.

Front 6

What happens when a substrate or an enzyme is phosphorylated?

Back 6

The exergonic phosphorylation reaction is coupled to an endergonic reaction. Can make the reactions that occur in cells exergonic.

Front 7

Energetic Coupling

Back 7

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

Front 8

Redox Reaction

Back 8

Any chemical reaction that involves the transfer of one or more electrons from one reactant to another. Drive the formation of ATP.

Front 9

Oxidation

Back 9

The loss of electrons from an atom during a redox reaction, either by donation of an electron to another atom or by the shared electrons in covalent bonds moving farther from the atomic nucleus.

Front 10

Reduction

Back 10

An atom's gain of electrons during a redox reaction, either by acceptance of an electron from another atom or by the electrons in covalent bonds moving closer to the atomic nucleus.

Front 11

Electron Donor

Back 11

A reactant that loses an electron and is oxidized in a redox reaction.

Front 12

Electron Acceptor

Back 12

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

Front 13

NAD+/NADH

Back 13

Oxidized and reduced forms, respectively, of nicotinamide adenine dinucleotide. A nonprotein electron carrier that functions in many of the redox reactions of metabolism.

Front 14

Electron Carrier

Back 14

Any molecule that readily accepts electrons from and donates electrons to other molecules.

Front 15

Cellular Respiration

Back 15

A common pathway for production of ATP, involving transfer of electrons from compounds with high potential energy to an electron transport chain and ultimately to an electron acceptor. Occurs in a plant's mitochondria.

Front 16

Four Steps in Cellular Respiration

Back 16

1. Glycolysis: see definition

2. Pyruvate Processing: forms acetyl CoA, another NADH produced

3. Citric Acid Cycle: acetyl CoA is oxidized to CO2, more ATP, NADH and FADH2 are produced

4. Electron transport and chemiosmosis: electrons from NADH and FADH2 move through an electron transport chain. The potential energy released is used to create a protein gradient across a membrane. This is used to make ATP.

Front 17

Oxidative Phosphorylation

Back 17

Production of ATP molecules from the redox reactions of an electron transport chain.

Front 18

Substrate-level Phosphorylation

Back 18

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

Front 19

Glycolysis

Back 19

A series of 10 chemical reactions that oxidize glucose to produce pyruvate, ATP, and NADH. Used by all organisms as part of fermentation or cellular respiration. Occurs in the cytosol. Regulated by feedback inhibition.

Front 20

Phosphofructokinase

Back 20

The enzyme that catalyzes synthesis of fructose-1,6-bisphosphate from fructose-6-phosphate, a key reaction in glycolysis.

Front 21

Feedback Inhibition

Back 21

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. A form of negative feedback.

Front 22

Regulatory Site

Back 22

A site on an enzyme to which a regulatory molecule can bind and affect the enzyme's activity; separate from the active site where catalysis occurs.

Front 23

Pyruvate Processing

Back 23

IN: pyruvate, NAD+, CoA

OUT: CO2, NADH, and acetyl CoA

Occurs in pyruvate dehydrogenase, which is located in the mitochondrial matrix. Regulated by both negative and positive control.

Front 24

Coenzyme A (CoA)

Back 24

A nonprotein molecule that is required for many cellular reactions involving transfer of acetyl groups (-COCH3)

Front 25

Acetyl CoA

Back 25

A molecule produced by oxidation of pyruvate in a reaction catalyzed by pyruvate dehydrogenase. Can enter the Citric Acid Cycle and also is used as a carbon source in the synthesis of fatty acids, steroids, and other compounds.

Front 26

Pyruvate Dehydrogenase

Back 26

A large enzyme complex, located in the inner mitochondrial membrane, that is responsible for conversion of pyruvate to acetyl CoA during cellular respiration.

Front 27

Citric Acid Cycle

Back 27

Krebs or TCA cycle. A series of 8 chemical reactions that starts with citrate and ends with oxaloacetate, which reacts with acetyl CoA to form citrate again. Part of the pathway that oxidizes glucose to CO2. Regulated by feedback inhibition. Occurs in the mitochondrial matrix. IN= acetyl groups

OUT= CO2, NADH, FADH2, and ATP or GTP

Front 28

Carboxylic Acids

Back 28

Organic acids with the form R-COOH

Front 29

Guanosine Triphosphate (GTP)

Back 29

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

Front 30

Electron Transport Chain (ETC)

Back 30

Any set of membrane-bound protein complexes and smaller soluble electron carriers involved in a coordinated series of redox reactions in which the potential energy of electrons transferred from reduced donors is successively decreased and used to pump protons from one side of a membrane to the other. Occurs in inner mitochondrial membrane.

Front 31

ATP Synthase

Back 31

A large-membrane bound protein complex in chloroplasts, mitochondria, and some bacteria that uses the energy of protons flowing through it to synthesize ATP.

Front 32

Coenzyme Q (ubiquinone)

Back 32

A nonprotein molecule that shuttles electrons between membrane-bound complexes in the mitochondrial electron transport chain.

Front 33

Proton-motive Force

Back 33

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 chloroplasts to power ATP synthesis via the mechanism of chemiosmosis.

Front 34

Chemiosmosis

Back 34

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

Front 35

Aerobic

Back 35

Referring to any metabolic process, cell, or organism that uses oxygen as an electron acceptor.

Front 36

Anaerobic

Back 36

Referring to any metabolic process, cell, or organism that uses an electron accpetor other than oxygen, such as nitrate or sulphate. Generate a smaller potential energy difference and make less ATP than aerobic cells.

Front 37

Fermentation

Back 37

Any of several metabolic pathways that make ATP by transferring electrons from a reduced compound such as glucose to a final electron acceptor other than oxygen. Allows glycolysis to proceed in the absence of oxygen.

Front 38

Lactic Acid Fermentation

Back 38

Catabolic pathway in which pyruvate produced by glycolysis is converted to lactic acid in the absence of oxygen.

Front 39

Alcohol Fermentation

Back 39

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

Front 40

Facultative Anaerobe

Back 40

Any organism that can perform aerobic respiration when oxygen is available to serve as an electron acceptor but that can switch to anaerobic respiration or fermentation when its not.

Front 41

Catabolic Pathway

Back 41

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

Front 42

Anabolic Pathway

Back 42

Any set of chemical reactions that synthesizes larger molecules from smaller ones. Generally requires an input of energy.