Module 4 Flashcards
Activation energy
the minimum amount of energy that must be provided to compounds to result in a chemical reaction.
Aerobic respiration
a metabolic catabolic process that captures electrons from a food substrate and captures energy for the cell via passing electrons down an electron transport chain to oxygen as the terminal electron acceptor.
Allosteric regulation
regulation of an enzyme by reversible noncovalent binding of an effector at a regulatory site that is distinct from the enzyme’s active site.
Anabolism
that part of metabolism dealing with the use of energy in biosynthesis, i.e., the joining together of monomer ‘building block’ units to generate the macromolecules of the cell.
Anaerobic respiration
a metabolic catabolic process that captures electrons from a food substrate and captures energy for the cell via passing electrons down an electron transport chain to a terminal electron acceptor other than oxygen.
ATP Synthase
a transmembrane multi-protein motor that catalyses synthesis of ATP from ADP and organic phosphate by capturing energy released by gated transport of H+ ions into the cell across the cytoplasmic membrane.
ATP
Adenosine triphosphate, the major energy currency within cells.
Autotroph
organism that can fix carbon from CO2.
Biochemical pathway
a series of chemical reactions carried out by proteins encoded by an organism to generate cellular metabolites, and/or to capture energy.
Biosynthesis
a multi-step, enzyme-catalyzed process where substrates are converted into more complex products in living organisms.
Calvin-Benson cycle
anabolic pathway used by many organisms to fix CO2.
Catabolism
that part of metabolism dealing with breaking down substrate/food molecules for energy and production of ‘building blocks’.
Catalyst
in chemistry, any substance that increases the rate of a reaction without itself being consumed.
Chemolithotroph
bacteria and archaea that capture energy by oxidation of inorganic molecules and use the reducing power for oxidative phosphorylation and for anabolic pathways.
chemoorganotrophs
organisms which use the chemical bonds in organic compounds or O2 as their energy source and obtain electrons or hydrogen from the organic compounds, including sugars (i.e., glucose), fats and proteins.
Chemotroph
organism that obtains energy from oxidation of organic or inorganic compounds.
Coenzyme
An organic non-protein compound that binds with an enzyme to catalyze a reaction.
Covalent modification of enzymes
altered activity of an enzyme/protein as a result of addition of a small group to a specific site on the protein.
Electron acceptor
in a redox reaction, the partner that receives an electron from the electron donor (i.e., it is reduced).
Electron donor
in a redox reaction, the partner that donates an electron to the electron acceptor (i.e., it is oxidized).
Electron transport chain (ECT)
a system of membrane embedded electron carriers that are ordered in a redox gradient in such a fashion as to pump H+ ions outside the membrane as electrons flow down the chain to the terminal electron acceptor.
Embden-Meyerhof pathway
a common metabolic pathway for degrading glucose to pyruvate.
Energy capture
the process by which energy is derived from external sources.
Entner-Doudoroff Pathway
a pathway for degrading glucose to pyruvate common in some Gram-negative bacteria.
Enzymes
proteins with catalytic activity.
Feedback inhibition
a process whereby the end product metabolite of a metabolic pathway binds allosterically to a regulatory enzyme in the pathway (usually the first dedicated step) to inhibit it.
Fermentation
a catabolic metabolic process that captures energy for the cell utilizing substrate level phosphorylation and electrons removed from the ‘food source’ are passed to an endogenous (within the cell) electron acceptor, often the end metabolite of the fermentation pathway.
ΔG
The change in Gibbs free energy. positive ΔG indicates a requirement for added energy (for a chemical reaction).
Negative ΔG
indicates a release of energy (for a chemical reaction)
positive ΔG
indicates a requirement for added energy (for a chemical reaction)
Gluconeogenesis
an anabolic pathway to generate glucose from pyruvate, basically runs glycolysis in reverse direction (with some novel enzymes).
Heterotroph
obtains carbon from organic molecules.
High-energy bonds
A chemical bond whose hydrolysis results in the generation of energy that, if coupled to an energetically unfavourable reaction, it can drive that reaction forward.
First law of thermodynamics
Law of Conservation of Energy, states that energy cannot be created or destroyed in an isolated system
Second law of thermodynamics
the entropy (measure of randomness or disorder of a system) of any isolated system always increases
Third law of thermodynamics
the entropy of a system approaches a constant value as the temperature approaches absolute zero
Lithotroph
organism that can obtain energy from inorganic molecules.
Macromolecule
complex molecules created via joining of simple structural units (monomers) together by repeating covalent bonds.
Metabolism
The chemical reactions related to harvesting, capturing, storing, and using energy for maintaining the state of a living cell.
Nicotinamide adenine dinucleotide (NAD+)
cellular enzyme cofactor that acts as an electron acceptor (or donor in its NADH + H+ form) and carries electrons within the cell between NAD-dependent enzymes.
Organotroph
chemotrophic organism that obtains energy from reduced organic compounds.
Redox Reactions
reactions in which electrons move from an electron donor to an electron acceptor.
Oxidation
The loss of electrons during a reaction.
Oxidative phosphorylation
The process by which ATP is synthesized using the energy from electron transport (via ATP synthase), which is driven by the oxidation of a chemical energy source.
Pentose phosphate pathway
a common metabolic pathway involving five carbon sugars and generating NADPH reducing power for biosynthetic reactions
Photosynthesis
process of both obtaining energy and reducing CO2 from energy and reducing power from light capture.
Phototroph
organism that obtains energy from light.
Post-translational regulation
regulation of enzyme activity or stability after completion of its translation into a mature enzyme
Precursor metabolites
intermediates of catabolic pathways that serve as the raw material for creation of monomer building blocks in anabolic pathways
Proton motive force
the combined chemical and electrical potential differences generated across the membrane generated by H+ transport coupled to electron transport.
Purines
heterocyclic, nitrogen-containing molecule with two joined rings that occurs in nucleic acids and other cell constituents, including adenine and guanine.
Pyrimidines
nitrogen-containing molecule with one ring that occurs in nucleic acids and other cell constituents; the most important being cytosine, thymine, and uracil.
Redox tower
a diagram with common redox participants in order from strong negative redox potential to strong positive redox potential.
Reduction
The gain of electrons during a reaction.
Respiration
a metabolic catabolic process that captures electrons from a food substrate and captures energy for the cell via passing electrons down an electron transport chain.
Standard reduction potential (E0)
A measure of the tendency of the donor of a half reaction to lose electrons at pH 7.
Substrate
a molecule acted upon by an enzyme.
Terminal electron acceptor
final recipient of electrons as they flow down an electron transport chain, for human and many bacteria, O2 serves as the final acceptor.
Transcriptional regulation
regulation of protein synthesis during transcription of mRNA, a primary control mechanism that effectively ‘turns on’ or ‘turns off’ the expression of a gene or sets of genes.
Translational regulation
regulation of protein synthesis through how efficiently the mRNA message is translated into a protein.
Tricarboxylic acid cycle (TCA cycle)
a common cyclic catabolic pathway that accepts two carbons from acetyl-CoA and proceeds through multiple steps to generate reducing power while realizing two carbons as CO2.
Krebs cycle
a common cyclic catabolic pathway that accepts two carbons from acetyl-CoA and proceeds through multiple steps to generate reducing power while realizing two carbons as CO2.
Citric acid cycle
a common cyclic catabolic pathway that accepts two carbons from acetyl-CoA and proceeds through multiple steps to generate reducing power while realizing two carbons as CO2.
