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90 Cards in this Set
- Front
- Back
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Ability to promote change or do work
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Energy
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energy associated with movement
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Kinetic
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energy due to structure or location
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Potential
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energy in molecular bonds
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Chemical energy
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conservation of energy, energy cannot be created or destroyed and can be transformed from one type to another
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First law of thermodynamics
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Transfer or transformation of energy from one form to another increases entropy or degree of disorder of a system
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Second law of thermodynamics
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involve an increase in entropy
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Energy transformations
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unusable energy, a measure of the disorder that cannot be harnessed to do work
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Entropy (S)
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reactions occur without input of additional energy and are not necessarily fast
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Spontaneous
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ΔG<0 or negative free energy change, is spontaneous
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Exergonic
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ΔG>0 or positive free energy change, requires addition of free energy and are not spontaneous
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Endergonic
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Glucose + phosphate → glucose-phosphate + H2O
ΔG = +3.3 Kcal/mole |
endergonic reaction
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ATP + H2O → ADP + Pi
ΔG = -7.3 Kcal/mole |
exergonic reaction
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Glucose + ATP → glucose-phosphate + ADP
ΔG = -4.0 Kcal/mole |
Coupled reaction:exergonic
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agent that speeds up the rate of a
chemical reaction without being consumed during the reaction |
Catalyst
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protein catalysts in living cells
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Enzymes
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RNA molecules with catalytic
properties |
Ribozymes
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Initial input of energy to start reaction
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Activation energy
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Activation energy allows molecules to get close enough to cause
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bond rearrangement
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2 common ways of overcoming activation energy
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heat and enzymes
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Straining bonds in reactants to make it easier to
achieve transition state |
Lowering activation energy
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location where reaction takes place
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Active site
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reactants that bind to active site
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Substrate
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formed when enzyme and substrate bind
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Enzyme-substrate complex
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plateau where nearly all active sites
occupied by substrate |
Saturation
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velocity of reaction near maximal rate
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Vmax
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substrate concentration at which velocity is
half maximal value |
Km
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Km is also called
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Michaelis constant
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there are ___ types of Inhibition
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2
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Molecule binds to active site and inhibits ability of substrate to bind, Km increases- more substrate needed
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Competitive inhibition
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Lowers Vmax without affecting Km and Inhibitor binds to allosteric site- not active site
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Noncompetitive
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small molecules permanently attached to the enzyme
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Prosthetic groups
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usually inorganic ion that temporarily binds to enzyme
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Cofactor
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organic molecule that participates in reaction but left unchanged afterward
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Coenzyme
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Most enzymes function maximally in a ______ range of temperature and pH
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narrow
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found in all living organisms
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Ribonuclease P (Rnase P)
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1 RNA and 1 protein subunit
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Ribonucleoprotein
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accelerates rate without being altered
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True catalyst
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a series of chemical reactions in which each step is coordinated by a specific enzyme
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metabolic pathways
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Result in breakdown and are exergonic
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Catabolic pathways
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Promote synthesis and are endergonic and must be coupled to exergonic reaction
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Anabolic pathways
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Breakdown of reactants and used for recycling
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Catabolic reactions
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A molecule such as ATP or NADH that stores energy and is used to drive endergonic reactions
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energy intermediate
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Used to obtain energy for endergonic reactions
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Catabolic reactions
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Substrate-level phosphorylation and Chemiosmosis
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2 ways to make ATP
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Enzyme directly transfers phosphate from one molecule to another molecule
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Substrate-level phosphorylation
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Energy stored in an electrochemical gradient is used to make ATP from ADP and Pi
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Chemiosmosis
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Also known as Oxidation-Reduction reactions
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Redox
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Removal of electrons
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Oxidation
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Addition of electrons
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Reduction
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Electron removed from one molecule is added to another
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Redox reaction
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Oxidized to make ATP and can donate electrons during synthesis reactions
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NADH
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Electrons removed by oxidation are used to
create ________ like NADH |
energy intermediates
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are biosynthetic reactions and make large macromolecules or smaller
molecules not available from food |
Anabolic reactions
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Each ATP undergoes _______ cycles of hydrolysis
and resynthesis every day |
10,000
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Particular amino acid sequences in proteins
function as |
ATP-binding sites
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On average, _____ of all proteins bind ATP
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20%
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Turn on or off genes
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Gene regulation
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Cell-signaling pathways like hormones
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Cellular regulation
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product of pathway inhibits early steps to prevent overaccumulation of product
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Feedback inhibition
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Feedback inhibition
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Biochemical regulation
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Biochemical regulation, Cellular regulation, and Gene regulation
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Regulation of metabolic pathways
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time it takes for 50% of the molecules to be broken down and recycled
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Half-life
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Most large molecules exist for a relatively ____period of time
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short
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All living organisms must efficiently use and _____ organic molecules
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recycle
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Expression of ______ allows cells to respond to changes in their environment
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genome
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made when needed and are broken down when they are not
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RNA and proteins
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Conserve energy by degrading mRNAs for proteins no longer required and remove faulty copies of mRNA
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mRNA degradation important
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Multiprotein complex uses exonucleases
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Exosome
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Enzyme that cleaves off nucleotides from the end of the RNA
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Exonuclease
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Lysosomes contain _______ to break down proteins, carbohydrates, nucleic acids, and lipids
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hydrolases
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recycling worn out organelles
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Autophagy
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a double membrane structure enclosing cellular material destined to be degraded , produced by the process of autophagy
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Autophagosome
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the primary pathway for protein degradation in archaea and eukaryotic cells is via a protein complex called
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proteasome
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enzymes that cleave the bonds between adjacent amino acids
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proteases
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sum total of all chemical reactions that occur within an organism
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metabolism
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process in which one or more substances are changed into other substances
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chemical reaction
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study of energy interconversions
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thermodynamics
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total energy
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enthalpy (H)
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usable energy-amount of available energy that can be used
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free energy (G)
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molecule that is a common energy source for all cells
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ATP
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process by which a a phosphate is directly transferred from ATP to glucose
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phosphorylation
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state in which the original bonds have stretched to their limit
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transition state
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enzymes recognize specific substrates
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specificity
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when substrate binds to an enzyme and the enzyme undergoes conformational changes that cause a tighter bind
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Induced fit
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degree of attraction between enzyme and its substrate
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affinity
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not active site
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allosteric site
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RNA molecule that catalyzes a chemical reaction
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ribozyme
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slowest step in a pathway
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rate-limiting step
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small protein in eukaryotic cells that directs unwanted proteins to a proteasome by its covalent attachment
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ubiquitin
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