Ch. 2 Flashcards
acid dissociation constant (Ka)
the equilibrium constant for the dissociation of an acid
acidosis
a metabolic condition of low pH (usually of the blood), reducing the body’s ability to buffer H+
adenylate system
a group of several phosphoryl transfer reactions that interconvert ATP, ADP, and AMP
aerobic respiration
a set of metabolic processes and reactions that uses oxygen to generate ATP
alkalosis
a metabolic condition of high pH (usually of the blood), reducing the body’s ability to buffer H+
anabolic pathway
a metabolic pathway for the biosynthesis of biomolecules from smaller precursors
biochemical standard free energy change (deltaG)
the amount of energy needed to go from the biochemical standard conditions at constant pressure (1 atm, or 101.3 kPa), temperature (298 K), pH 7, and 55.5 M concentration of H2O, where all reactants and products are present initially at 1 M concentrations, to the condition at which all reactants and products have reached equilibrium concentrations
bioenergetics
energy conversion processes in biological systems, including transformation of solar energy into chemical energy and interconversion of chemical energy through oxidation and reduction of organic molecules
biological membrane
a physical barrier in a living system, most often consisting of nonpolar molecules with hydrophobic properties to partition aqueous compartments
biosphere
all the living organisms on earth, considered as a whole
bomb calorimeter
a device in which a compound is combusted by a spark at constant volume in the presence of pure oxygen (completely oxidized); the amount of heat exchanged between the reaction chamber and a surrounding water jacket is a measure of enthalpy change
buffer
an aqueous solution that resist changes in pH because of the protonation or deprotonation of an acid-base conjugate pair
calorie (cal)
a unit of energy; the amount of heat energy required to raise 1 gram of water by 1 degree C using a calorimeter; a Calorie is 10^3 calories, or 1 kilocalorie (kcal), which is equal to 4.184 kilojoules (kJ)
carbon fixation
the conversion of carbon dioxide into other organic compounds, particularly glucose; often considered as part of photosynthesis
catabolic pathway
a metabolic pathway that converts energy-rich compounds into energy-depleted compounds, releasing energy for the cell
colligative properties
physical properties of a solution that depend on the number of solute particles, such as freezing-point depression or osmotic pressure
conjugate base
the deprotonated species of an acid; the anion of a weak acid
contractile vacuole
an organelle in some unicellular organisms that helps regulate osmosis by collecting and expelling water from the cell
endergonic
a chemical reaction that requires energy and is unfavorable in the direction written; it has a deltaG > 0
endomembrane system
an intracellular network of lipid bilayers that is used to exchange material through vesicle transport
endothermic
a reaction that absorbs heat, and deltaH > 0
energy charge (EC)
a measure of the energy state of a cell in terms of ATP, ADP, and AMP ratios:
EC= ([ATP]+ 0.5[ADP]) / ([ATP]+[ADP]+[AMP])
enthalpy (H)
the heat content of a system
entropy
a measure of the spreading of energy; also a measure of the disorder (randomness) in a system
equilibrium
the state of a system in which no net change occurs
equilibrium constant (Keq)
a measure of the directionality of a reaction under standard conditions, where all products and reactants start at 1 M and proceed to their equilibrium concentration
equivalent
the amount of base (OH-) needed to deprotonate an acid; the amount of substance that will react with 1 mol of electrons in a redox reaction
erythrocyte
a red blood cell; contains hemoglobin for oxygen transport in an organism
exergonic
a chemical reaction that releases energy and is favorable in the direction written; it has a deltaG < 0
exothermic
a reaction that releases heat, and deltaH < 0