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85 Cards in this Set

  • Front
  • Back
selective permeability
biological property of membrane that allows some substances cross more easily than others
amphipathic molecule
molecules with a hydrophobic and hydrophilic region
fluid mosaic model
fluid model that contains a mosaic of proteins embedded in the phospholipid bilayer
integral proteins
transmembrane protein that has hydrophobic regions that completely span the hydrophobic interior of the membrane
peripheral proteins
protein that is not attached to the bilayer itself but its appendages are loosely bound to surface of the membrane
membrane carbohydrates that are covalently bonded to lipids
membrane carbohydrates that are covalently bonded to proteins
transport protein
transmembrane proteins that help substances to cross the membrane
a transport protein in the plasma membrane that allows for osmosis to occur
tendency for molecules of any substance to spread out evenly into the available space
concentration gradient
increase/decrease in the density of a chemical substance in an area
passive transport
diffusion of a substance across a biological membrane
diffusion of water across a selectively permeable membrane
ability of a solution to cause a cell to gain or lose water
same solute concentration in both solutions
in comparing 2 solutions, the solution with the higher solute concentration
in comparing 2 solutions, the solution with the lower solute concentration
how organisms manage the solute concentrations and balance the gain/loss of water
when the wall of a cell becomes firm due to the interior of the cell having a higher concentration than the outside resulting in entry of water
phenomenon that occurs when the cytoplasm shrivels and the plasma membrane begins to pull away from the cell wall due to loss of water to a hypertonic environment
facilitated diffusion
spontaneous passage of molecules/ions with the help of carrier proteins across biological membrane down their concentration gradients
ion channels
protein channels in a cell membrane that allow the passage of specific ions down its concentration gradient
gated channels
protein channels in a cell membrane that open/close due to presence of a chemical stimulus
active transport
pumping a molecule across a membrane against its concentration gradient relies on energy input and transport proteins
sodium-potassium pump
active transport mechanism where the plasma membrane pumps Na ions out of the cell and pumps K into the cell against the concentration gradient
membrane potential
charge difference created between a cell's cytoplasm and extracellular fluid
electrochemical gradient
diffusion gradient of an ion, representing a type of potential energy that accounts for the concentration difference of the ion across a membrane and its tendency to move relative to the membrane potential
electrogenic pump
ion transport protein that generates voltage across a membrane
proton pump
active transport mechanism in cell membranes that uses ATP to pump H ions out of the cell
secretion of macromolecules by vesicle fusion to the plasma membrane
cellular uptake of macromolecules and substances that are then surrounded by localized regions of DNA and pinched off as intracellular vesicles
molecules that bind to a specific receptor site of another molecule
totality of an organism's chemical reactions
metabolic pathway
a specific molecules is altered by specific enzymes in a series of steps that leads to an altered product
catabolic pathways
degradative processes that release energy by breaking down complex molecules into simpler ones
anabolic pathways
process requires energy to build complex molecules from simpler ones
study of how an organism manages its energy resources
capacity to cause change or rearrangement in a collection of matter
kinetic energy
energy of motion
kinetic energy due to random molecular motion
potential energy
energy that nonmoving object possesses due to its location and structure
chemical energy
potential energy available for release in a chemical reaction
study of energy transformations in a collection of matter
1st law of thermodynamics
energy of universe is constant, energy is transferred/transformed but cannot be created/destroyed
2nd law of thermodynamics
when energy is transferred or transformed there is an increase in the entropy of the universe
free energy
amount of energy in a system that can perform work when temperature and pressure are uniform throughout
exergonic reaction
reaction that proceeds with a net release of energy
endergonic reaction
reaction that requires an absorption of energy from its surroundings
energy coupling
use of an exergonic reaction to power an endergonic one
contains sugar ribose, nitrogenous base adenosine and 3 phosphate groups bonded to it
the molecule that serves as the recipient of a phosphate group
chemical agent that speeds up a reaction w/o being consumed by it
catalytic protein that speeds up a reaction w/o being consumed by it
activation energy
initial investment of energy for starting a reaction
reactant to which enzyme acts on
active site
restricted region on an enzyme that binds to its substrate
induced fit
chemical groups on active sites fitting together in a way that enhances their ability to catalyze a reaction
nonprotein helpers required by enzymes for catalytic activity
cofactors of organic enzymes
competitive inhibitors
reduce productivity of an enzyme by blocking its substrate from entering active sites
noncompetitive inhibitors
do not directly compete with substrates to bind to the enzyme at the active site
allosteric regulation
describes cases in which protein function at one site affects the binding of a regulatory molecule on another
mechanism amplifies reactivity of enzymes to substrates
feedback inhibition
inhibitory binding of an endproduct to an enzyme early in the pathway that switches off the metabolic pathway
partial degradation of sugars without use of oxygen
cellular respiration
catabolic pathway in which oxygen is consumed to produce ATP
reducing agent
electron donor
oxidizing agent
electron acceptor
electron acceptor that serves as an oxidatizing agent in respiration
electron transport chain
used in respiration to break the fall of electrons to oxygen in a series of energy-releasing steps
process that converts glucose to 2 molecules of pyruvate in the cytosol
citric acid cycle
takes place in the mitochondrial matrix that completely breaks down glucose by oxidizing a derivative of pyruvate to carbon dioxide
oxidative phosphorylation
production of ATP using energy derived from redox reactions of an electron transport chain
substrate-level phosphorylation
transferring a phosphate from a substrate model to ADP to produce ATP
acetyl coA
entry compound to the citric acid cycle that is formed from a fragment of pyruvate attached to a coenzyme
iron-containing compounds used in the electron transport chain in mitochondria/chloroplasts
ATP synthase
located in the inner membrane of the mitochondrion, the enzyme attaches an inorganic phosphate group to ADP to make ATP
process in which energy is stored in the form of a hydrogen ion gradient that is used to drive cellular work
proton-motive force
potential energy stored in the form of an electrochemical gradient generated by pumping of hydrogen ions across membranes during chemiosmosis
lacking oxygen referring to organisms, environment, cellular processes that may be poisoned by it
need for oxygen by organisms, environment, and cellular processes
alcohol fermentation
conversion of pyruvate to carbon dioxide and ethyl alcohol
lactic acid fermentation
conversion of pyruvate to lactate without the release of carbon dioxide
facultative anaerobes
organisms that generate enough ATP to survive through respiration or fermentation
beta oxidation
metabolic sequence that breaks down fatty acids to 2 carbon fragments which enter the citric acid cycle as acetyl coA