bio 101 exam 3 Flashcards
voltage across a membrane
membrane potential
molecule with one part hydrophilic, one part hydrophobic
amphipathic
moveable structure that is a mixture of proteins drifting in the a bilayer of phospholipids
fluid mosaic model
influenced by fatty acid, cholesterol and temperature of a membrane
fluidity
buffer to keep membrane from becoming too fluid or viscous
cholesterol
moves ions and other molecules across membrane
transport proteins
allows cell to receive signals from the environment
receptors
catalyze chemical reactions
enzymes
permanently associate with a membrane, embedded in the interior of the lipid bilayer
integral membrane proteins
temporarily associated with lipid bilayer or integral membrane proteins
peripheral proteins
proteins that go all the way from one side of the bilayer membrane to the other
transmembrane proteins
membrane allows some substances to cross more easily than others
selective permeability
membrane transport that requires no energy input
passive transport
spontaneous net movement of particles down a concentration gradient
diffusion
when a solute is more concentrated in one area than another
concentration gradient
diffusion of water across a selectively permeable membrane
osmosis
transport proteins help polar molecules and ions diffuse across a membrane down a concentration gradient with protein channels or carriers
facilitated diffusion
a solution’s ability to alter a cell’s shape by controlling the amount of water in it
tonicity
lower concentration of solute (too much water), can swell and burst
hypotonic
higher concentration of solute (not enough water) can shrivel and die
hypertonic
equal concentration of solute, cell volume stable
isotonic
change shape to provide corridors that allow specific molecules or ions to cross membrane
carrier proteins
gated passages that open to let ions in without changing shape (like a straw)
channel proteins
carrier proteins specifically for water’s passage (function in osmosis)
aquaporins
solutes move AGAINST concentration gradient using carrier transport proteins, requiring ATP
active transport
type of electrogenic pump for animals, carrier protein pumps out 3 Na ions for ever 2 K ions that are pumped in, higher K concentration inside, higher Na concentration outside
sodium-potassium pump
electrogenic pump in plants, fungi and bacteria, active transport of H+ ions out of cell AGAINST concentration gradient
proton pumps
transport protein that generates voltage across a membrane, storing energy that can be used for cellular work
electrogenic pump
charge difference across cell membrane through active transport of ions
electrochemical gradient
transport protein that couples the diffusion of one substance of doing down its concentration gradient with one that is going against it
cotransport
molecules brought into the cell (membrane pinches to form vesicles)
endocytosis
secretion of molecules outside the cell (vesicle spits materials out of membrane)
exocytosis
controlling of cell pressure by regulating salt and water concentrations
osmoregulation
sucks up and expels excess water in the cell in some protozoans
contractile vacuoles
large storage of water in the middle of plant cells
central vacuole
ideal state for plant cells, swollen and rigid, hypotonic
turgid
floppy and loose in plant cells, isotonic
flaccid
shrinking of plant cell contents away from cell walls due to lack of water, hypertonic conditions
plasmolysis
active transport that uses energy directly from ATP
primary active transport
active transport that uses energy from ionic concentration differences between sides of a membrane
secondary active transport
force that promotes movement of protons across membrane to create an electrochemical gradient
proton motive force (pmf)
carbohydrates covalently bonded to lipids
glycolipids
carbohydrates covalently bonded to proteins
glycoproteins
how low temps influence membrane fluidity
more rigid
how high temps influence membrane fluidity
more viscous
direction that phospholipids and proteins move in a membrane
lateral
type of molecules the hydrophobic membrane interior allows the passage of
other hydrophobic molecules
how often are hydrophilic molecules permeable to the membrane
hardly ever
what kind of passage are small molecules given in a selectively permeable membrane
slow passage, even if they are polar
substances that constantly pass through the selectively permeable membrane
sugars, amino acids, O2, CO2, ions
cell engulfs food particles and creates food vesicles
phagocytosis
cell gulps drops of extracellular fluid into vesicles
pincytosis
cell gulps drops of extracellular fluid containing certain materials into vesicles
receptor-mediated endocytosis
when unneeded materials in the cell are digested and their nutrients recycled
autophagy
membrane proteins that allow temporary binding
cell-cell recognition
membrane proteins that create gap junctions and tight junctions
intercellular joining
membrane proteins that attach to ECM or cytoskeleton, stablizing
anchors
entire set of chemical reactions in an organism
metabolism
release of energy by the breakdown of large molecules
catabolism
consuming energy to build larger molecules
anabolism
capacity to cause change in a system
energy
energy of motion
kinetic energy
kinetic energy associated with random movement of atoms and molecules
thermal energy
stored energy due to position
potential energy
energy available for release in a chemical reaction
chemical energy
first law of thermodynamics
energy is neither created nor destroyed
second law of thermodynamics
when energy is transferred or transformed, there is a loss of energy available to do work
energy can be transferred from one object to another
thermodynamics
measure of disorder, randomness
entropy
process that occurs naturally without an outside force acting upon it or addition of energy
spontaneous process
measure of energy available to do work
free energy
spontaneous reaction, energy released, ΔG is negative
exergonic
nonspontaneous reaction, energy required, ΔG is positive
endergonic
source of energy to do most cellular work
adenosine triphosphate (ATP)
exergonic reaction drives an endergonic reaction
energetic coupling
phosphate group from ATP transferred to the reactant during energetic coupling
phosphorylated intermediate
catabolic pathway that breaks down organic molecules for production of ATP
cellular respiration
full breakdown of molecules using oxygen
aerobic respiration
reactions that transfer e- from one molecule to another
redox reactions
molecules that are both reduced and oxidized in cellular respiration as they accept and donate e-
electron carriers
main carrier molecule of cellular respiration
NAD+/NADH
second carrier molecule that functions in the citric acid cycle only
FAD/FADH
loss of electrons
oxidation
addition of electrons
reduction
series of proteins in the mitochondrial inner membrane
electron transport chain (ETC)
enzyme transfers a phosphate group from substrate to ADP to make ATP
substrate level phosphorylation
partial breakdown of organic molecules without oxygen
fermentation
anerobic process in the cytosol where one glucose is partially oxidized into two pyruvate molecules
glycolysis
product of glucose and reactant of acetyl CoA
pyruvate
process after glycolysis and before citric acid cycle where pyruvate goes to acetyl CoA
pyruvate oxidation
a coenzyme that is integral to the citric acid cycle of cellular respiration
acetyl CoA
