Chapter 14: Energy Generation In Mitochondria And Chloroplasts

Front 1

antenna complex

Back 1

captures light energy in a photosystem

Front 2

ATP synthase

Back 2

membrane-associated enzyme complex that catalyzes the formation of ATP during oxidative phosphorylation and photosynthesis; found in mitochondria, chloroplasts, and bacteria

Front 3

carbon fixation

Back 3

process by which green plants incorporate carbon atoms from atmospheric carbon dioxide into sugars; the second stage of photosynthesis

Front 4

chemiosmotic coupling

Back 4

mechanism in which a gradient of hydrogen ions (a pH gradient) across a membrane is used to drive an energy-requiring process, such as ATP production or the transport of a molecule across a membrane

Front 5

chlorophyll

Back 5

light-absorbing pigment that plays a central part in photosynthesis

Front 6

chloroplast

Back 6

specialized organelle in algae and plants that contains chlorophyll and in which photosynthesis takes place

Front 7

cyclic photophosphorylation

Back 7

photosynthetic process involving photosystem I only, by which chloroplasts can generate ATP without making NADPH

Front 8

cytochrome

Back 8

colored, heme-containing protein that transfers electrons during cellular respiration and photosynthesis

Front 9

cytochrome oxidase

Back 9

a protein complex that receives electrons from cytochrome c, thus oxidizing it; it then donates these electrons to oxygen

Front 10

electron-transport chain

Back 10

a series of membrane-embedded electron carrier molecules along which electrons move from a higher to a lower energy level, as in oxidative phosphorylation and photosynthesis

Front 11

iron-sulfur center

Back 11

one of a family of electron transporters containing iron atoms linked to sulfur atoms and cysteine side chains; found in electron-transport chains such as those in mitochondria and chloroplasts

Front 12

matrix

Back 12

most generally, a space within which something is formed; in cell biology, it often refers to the large internal compartment of the mitochondrion, which contains a concentrated mixture of special enzymes that catalyze oxidation reactions, as well as the mitochondrial genome and the proteins needed to express mitochondrial genes

Front 13

mitochondrion

Back 13

membrane-enclosed organelle, about the size of a bacterium, that carries out oxidative phosphorylation and produces most of the ATP in eucaryotic cells

Front 14

nitrogen fixation

Back 14

conversion of nitrogen from the atmosphere into nitrogen-containing organic molecules by soil bacteria and cyanobacteria

Front 15

oxidative phosphorylation

Back 15

process in bacteria and mitochondria in which ATP formation is driven by the transfer of electrons from food molecules to molecular oxygen; involves the intermediate generation of a pH gradient across a membrane and chemiosmotic coupling

Front 16

photosynthesis

Back 16

the process by which plants and some bacteria use the energy of sunlight to drive the synthesis of organic molecules from carbon dioxide and water

Front 17

photosystem

Back 17

large multiprotein complex containing chlorophyll that captures light energy

Front 18

quinone

Back 18

small, lipid-soluble, mobile electron carrier molecule found in the respiratory and photosynthetic electron-transport chains

Front 19

reaction center

Back 19

in photosynthetic membranes, a protein complex that contains a specialized pair of chlorophyll molecules that performs photochemical reactions to convert the energy of photons (light) into high-energy electrons for transport down the photosynthetic electron-transport chain

Front 20

redox pair

Back 20

two molecules in which one acts as an electron donor and one as an electron acceptor in an oxidation-reduction reaction; for example, NADH (electron donor) and NAD+ (electron acceptor)

Front 21

redox potential

Back 21

a measure of the tendency of a given redox pair to donate electrons (act as a reducing agent) or to accept electrons (act as an oxidizing agent)

Front 22

redox reaction

Back 22

when electrons are transferred from one chemical species to another; an oxidation-reduction reaction

Front 23

stroma

Back 23

the connective tissue in which a glandular or other epithelium is embedded; the large interior space of a chloroplast, containing enzymes that incorporate carbon dioxide into sugars in the carbon-fixation stage of photosynthesis