Ch 14 - Energy Generation in Mitochondria and Chloroplasts Flashcards
antenna complex
in chloroplasts and photosynthetic bacteria, the part of the membrane-bound photosystem that captures energy from sunlight; contains an array of proteins that bind hundreds of chlorophyll molecules and other photosensitive pigments
ATP synthase
abundant membrane-associated enzyme complex that catalyzes the formation of ATP from ADP and inorganic phosphate during oxidative phosphorylation and photosynthesis
carbon fixation
process by which green plants and other photosynthetic organisms incorporate carbon atoms from atmospheric carbon dioxide into sugars. the second stage of photosynthesis
cell respiration
process by which cells harvest the energy stored in food molecules; usually accompanied by the uptake of O2 and release of CO2
chemiosmotic coupling
mechanism that uses the energy stored in a transmembrane proton gradient to drive an energy-requiring process, such as the synthesis of ATP by ATP synthase or the transport of a molecule across a membrane
chlorophyll
light-absorbing green pigment that plays a central part in photosynthesis
chloroplast
specialized organelle in algae and plants that contains chlorophyll and serves as the site for photosynthesis
cytochrome
a family of membrane-bound, colored, heme-containing proteins that transfers electrons during cellular respiration and photosynthesis
cytochrome c oxidase
protein complex that serves as the final electron carrier in the respiratory chain; removes electrons from cytochrome c and passes them to O2 to produce H2O
electron-transport chain
a series of membrane-embedded electron carrier molecules that facilitate the movement of electrons from a higher to a lower energy level, as in oxidative phosphorylation and photosynthesis
iron-sulfur center
tightly bound metal complex that carries electrons in proteins that operate early in the electron-transport chain; has a relatively weak affinity for electrons
light reactions
in photosynthesis, the set of reactions that converts the energy of sunlight into chemical energy in the form of ATP and NADPH (stage 1 of photosynthesis)
matrix
large internal compartment within a mitochondrion
mitochondrion
membrane-enclosed organelle, about the size of a bacterium, that carries out oxidative phosphorylation and produces most of the ATP in eukaryotic cells
nitrogen fixation
conversion of nitrogen gas from the atmosphere into nitrogen-containing molecules by soil bacteria and cyanobacteria; requires a great deal of energy
oxidative phosphorylation
membrane-based process in bacteria and mitochondria in which ATP formation is driven by the transfer of electrons from food molecules to molecular oxygen
photosynthesis
the process by which plants, algae and some bacteria use the energy of sunlight to drive the synthesis of organic molecules from carbon dioxide and water
photosystem
large multiprotein complex containing chlorophyll that captures light energy and converts it into chemical-bond energy; consists of a set of antenna complexes and a reaction center
quinone
small, lipid-soluble, mobile electron carrier molecule that functions in the respiratory and photosynthetic electron-transport chains
reaction center
in photosynthetic membranes, a protein complex that contains a special pair of chlorophyll molecules; it performs the photochemical reactions that convert the energy of photons (light) into high-energy electrons for transport down the photosynthetic electron-transport chain
redox pair
two molecules that can be interconverted by the gain or loss of an electron; for example NADH and NAD+
redox potential
a measure of the tendency of a given redox pair to donate or accept electrons
redox reaction
a reaction in which electrons are transferred from one chemical species to another. an oxidation-reduction reaction
respiratory enzyme complex
set of proteins in the inner mitochondrial membrane that facilitates the transfer of high-energy electrons from NADH to water while pumping protons into the intermembrane space
