Unit 2 Metabolic Processes Flashcards
the sum of all chemical reactions in a cell or organism
metabolism
the energy of motion
kinetic energy
the stored energy that an object possesses as a result of its position relative to other objects or to its internal structure
potential energy
principle that states that energy can be transferred or transformed, but it cannot be created or destroyed
first law of thermodynamics
the minimum amount of energy that is required to break a particular type of bond; measured in kJ/mol of bonds
bond energy
the minimum amount of energy that chemical reactants must absorb to start a reaction
activation energy
a temporary condition during a chemical reaction in which the bonds in the reactants are breaking and the bonds in the products are forming
transition state
a chemical reaction in which energy is absorbed, giving the products more chemical potential energy than the reactants
endothermic reaction
a chemical reaction in which energy is released, leaving the products with less chemical potential energy than the reactants
exothermic reaction
principle that states that every time energy is converted to another form, some of the energy becomes unusable
second law of thermodynamics
a measurement of disorder in a system
entropy
a change that will, once begun, continue on its own under a given set of conditions; does not require a continuous supply of energy
spontaneous change
energy that can do useful work; also called Gibbs free energy
free energy
a chemical reaction that releases free energy; the products have less free energy than the reactants
exergonic reaction
a chemical reaction that absorbs free energy; the products have more free energy than the reactants
endergonic reaction
the transfer of energy from one reaction to another in order to drive the second reaction
energy coupling
a pathway in which energy is released and complex molecules are broken down into simple molecules
catabolic pathway
a pathway in which energy is supplied to build complex molecules from simple molecules
anabolic pathway
the transfer of a phosphate group, usually from ATP, to another molecule
phosphorylation
the cyclic and ongoing breakdown and re-synthesis of ATP
ATP cycle
an enzyme that oxidizes a substrate and transfers hydrogen ions to an acceptor
dehydrogenase
the reduced form of the coenzyme nicotinamide adenine dinucleotide
NADH
a process that uses oxygen to harvest energy from organic compounds
aerobic cellular respiration
an organism that cannot live without oxygen
obligate aerobe
the formation of ATP by the direct transfer of a phosphate group from a substrate to ADP
substrate level phosphorylation
a process that forms ATP using energy transferred indirectly from a series of redox reactions
oxidative phosphorylation
a series of reactions in which a glucose molecule is broken into two pyruvate molecules and energy is released
glycolysis
a reaction in which pyruvate is oxidized by NAD+ and CO2 is removed, forming an acetyl group and releasing NADH
pyruvate oxidation
a process that uses an organic compound as the final oxidizing agent to produce energy
fermentation
a process that uses a final inorganic oxidizing agent other than oxygen to produce energy
anaerobic respiration
an organism that cannot survive in the presence of oxygen
obligate anaerobe
an organism that can live with or without oxygen
facultative anaerobe
a cyclic series of reactions that transfers energy from organic molecules to ATP, NADH, and FADH2 and release carbon atoms as CO2.
citric acid cycle
the removal of a hydrogen atom from a molecule
dehydrogenation
a chemical reaction that removes a carboxyl group to form CO2
decarboxylation reaction
a difference in proton (H+ ion) concentration across a membrane
proton gradient
a force that moves protons because of a chemical gradient (often referred to as an electrochemical gradient) of protons across a membrane
proton-motive force
a process in which ATP is synthesized using the energy of an electrochemical gradient and the ATP synthase enzyme
chemiosmosis
the amount of energy that is expended per unit time in an organism
metabolic rate
the metabolic rate of an organism at rest
basal metabolic rate
a process in which fatty acids are broken down into acetyl-CoA through catabolism
beta-oxidation
a process in which pyruvate is decarboxylation, producing a molecule each of CO2, and of ethanol, and NAD+
alcohol fermentation
a process in which pyruvate reacts with NADH and is converted directly into lactate and regenerates NAD+
lactate fermentation
the first stage of photosynthesis, during which water molecules are split as light energy is absorbed and transformed into chemical energy in ATP and NADPH
light dependent reactions
the second stage of the photosynthesis process that uses ATP and NADPH to convert CO2 to sugars
Calvin cycle
a molecule capable of accepting electrons and becoming reduced during photosynthesis
primary electron acceptor
a cluster of light-absorbing pigments embedded in the thylakoid membrane able to capture and transfer energy to special chlorophyll a molecules in the reaction centre
antenna complex
a complex of proteins and pigments that contains the primary electron acceptor
reaction centre
a plot of the amount of light energy of various wavelengths that a substance absorbs
absorption spectrum
a plot of the effectiveness of light energy of different wavelengths in driving a chemical process
action spectrum
a collection of pigment proteins that includes chlorophyll a and absorbs light at the 700 nm wavelength
photosystem 1
a collection of pigment proteins that includes chlorophyll a and absorbs light at the 680 nm wavelength
photosystem 11
ribulose 1,5-bisphosphate carboxylase oxygenase; a critical enzyme that acts as a catalyst for the reduction of carbon dioxide in the Calvin cycle of photosynthesis
ribisco
the catalysis of O2 instead of CO2 by rubisco into RuBP, which slows the Calvin cycle, consumes ATP, and results in a release of carbon
photorespiration
small pores in the surface of a leaf that can be opened and closed to control the exchange of gases between the atmosphere and the leaf interior
stomata
an alternative form of carbon fixation that some plants use, particularly in hot weather, to increase the concentration of CO2 available for the Calvin cycle reactions
C4 cycle
a metabolic pathway, used mostly by succulent plants, in which the Calvin cycle and the C4 cycle are separated in time for better efficiency of CO2 fixation
crassulacean acid metabolism (CAM)
