Chapter 14 - Vocab Flashcards
metabolism
the total of all degradative and biosynthetic cellular reactions
catabolism
the degradative metabolic reactions in which nutrients and cell constituents are broken down for energy and raw materials
anabolism
the reactions by which biomolecules are synthesized from simpler components
nutrition
the intake and utilization of food as a source of raw materials and free energy
autotroph
an organism that can synthesize all its cellular components from simple molecules using the energy obtained from sunlight (photoautotroph) or from the oxidation of inorganic compounds (chemolithotroph)
chemolithotroph
an autotrophic organism that obtains energy from the oxidation of inorganic compounds
photoautotroph
an autotrophic organism that obtains energy from sunlight
heterotroph
an organism that obtains free energy from the oxidation of organic compounds produced by other organisms
anaerobe
an organism that does not us O2 as an oxidizing agent for nutrient breakdown; an obligate anaerobe cannot grow in the presence of 02, whereas a facultative anaerobe can grow in the presence or absence of O2
aerobe
an organism that uses O2 as an oxidizing agent for nutrient breakdown
macronutrient
a nutrient that is required in relatively large amounts, such as proteins, carbohydrates, and fats
micronutrient
a nutrient that is required in relatively small amounts, such as vitamins and minerals
vitamin
a metabolically required organic substance that cannot be synthesized by an animal and must therefore be obtained from its diet
mineral
an inorganic substance required for metabolic activity, including sodium, potassium, chloride, and calcium; minerals such as iron, copper, and zinc, which are required in small amounts, are known as trace elements
metabolite
a reactant, intermediate, or product of a metabolic reaction
oxidation
the loss of electrons; oxidation of a substance is accompanied by the reduction of another substance
reduction
the gain of electrons; reduction of a substance is accompanied by the oxidation of another substance
isozyme
enzymes that catalyze the same reaction but are encoded by different genes (aka “isoforms”)
near-equilibrium reaction
a reactions whose change in free energy value is close to zero, so that it can operate in either direction depending on the substrate and product concentrations
flux
(1) the rate of flow of metabolites through a metabolic pathway
(2) the rate of transport per unit area
substrate cycle
two opposing sets of metabolic reaction that, in many cases, function together to hydrolyze ATP, but provide a control point for regulating metabolic flux (aka “futile cycle”)
“high-energy” intermediate
a substance whose degradation is highly exergonic (yield as much free energy as is required to synthesize ATP from ADP + Pi >=30.5 kJ/mol under standard biochemical conditions) (aka “energy-rich” compound)
orthophosphate cleavage
the hydrolysis of ATP that yields ADP + Pi
pyrophosphate cleavage
the hydrolysis of ATP that yields AMP + PPi
substrate-level phosphorylation
the direct transfer of a phosphoryl group to ADP to generate ATP
oxidative phosphorylation
the process by which the free energy obtained from the oxidation of metabolic fuels is used to generate ATP from ADP + Pi
photophosphorylation
the synthesis of ATP from ADP + Pi coupled to the dissipation of a proton gradient that has been generated through light-driven electron transport
kinase
an enzyme that transfers a phosphoryl group between ATP and another molecule
phosphagen
a phosphoguanidine whose phosphoryl group-transfer potential is greater than that of ATP; these compounds can therefore phosphorylate ADP to generate ATP
reducing agent
a substance that can donate electrons, thereby reducing another substance and becoming oxidized
oxidizing agent
a substance that can accept electrons, thereby oxidizing another substance and becoming reduced
half-reaction
the single oxidation or reduction process, involving an electron donor and its conjugate electron acceptor, that occurs in electrical cells but requires direct contact with another such reaction to form a complete oxidation-reduction reaction
redox couple
an electron donor and acceptor that from a half-reaction (aka “conjugate redox pair”)
conjugate redox pair
and electron donor and acceptor that form a half-reaction (aka “redox couple”)
electrochemical cell
a device in which two half-reactions occur in separate compartments linked by a wire for transporting electrons and a salt bridge for maintaining electrical neutrality; the simultaneous activity of the half-reactions forms a complete oxidation-reduction reaction
reduction potential
a measure of the tendency of a substrate to gain electrons
Nernst equation
an expression of the relationship between reduction potential difference and the concentrations of the electron donors and acceptors
Faraday
the electrical charge of one mole of electrons (96,485 C/mol)
