What is the purpose of the cell membrane
controls what goes in and out of the cell
movement of molecules without the use of any chemical energy (ATP)
passive transport
simplest type of passive transport; it can happen with liquids (food coloring spreading), solids (sugar dissolving), gas (fart spreading)
diffusion
In which direction does the diffusion occur?
High to low concentration
the difference in the concentration of a substance across a distance
concentration gradient
What supplies the energy for diffusion?
kinetic energy
Molecules are constantly _____, even at equilibrium (vibrating in place in a solid)
in motion
3 things that determine if a molecule will be able to diffuse across the membrane
size, solubility, charge
Name 2 parts of a solution
solute & solvent
WATER tends to diffuse from _________ to __________ solutions
hypotonic, hypertonic
What structure on the outside of a plant cell keeps them from rupturing from too much water?
cell wall
plant cell central vacuole big; pressing up against cell wall
turgor pressure
animal cell gets big; can burst because of too much water entering them
cytolysis
Diffusion of water through a selectively permeable membrane
osmosis
Which way does the water move if the solutes outside of the cell is hypotonic to the cytosol
into cell
Which way does the water move if the outside of the cell is hypertonic to the cytosol
out of cell
If the inside and outside of a cell are both isotonic and have reached equilibrium, does water still move across the cell membrane?
yes but at equal rates
plant cell central vacuole small; when the vacuole breaks away from the plasma membrane and shrinks bc water is leaving the cell
plasmolysis
type of passive transport that helps make it easier for large molecules like sugar get across the membrane
facilitated diffusion
transport protein that transport ions across the membrane; can be open or closed (gated)
ion channels
3 stimuli that open & close gated channels
stretching the cell membrane, electrical signals, chemical signals
the state that exists when the concentration of a substance is the same throughout a space
equilibrium
when the solute concentration outside the cell is lower than that in the cytosol, and water will diffuse into the cell; ex. pure water
hypotonic
when the solute concentration outside the cell is higher than that in the cytosol, and the water will diffuse out of the cell; ex. syrup
hypertonic
when the solute concentrations outside and inside the cell are equal and there will be no net movement of water
isotonic
in protists, an organelle that accumulates water and then releases it periodically to maintain osmotic pressure
contractile vacuole
an integral protein that helps transport substances across a cell membrane in facilitated diffusion
carrier protein
movement of molecules across the cell membrane from an area of lower concentration to an area of higher concentration WITH use of chemical energy (ATP)
active transport
a protein pump that uses ATP to actively transport 3 Na+ ions out of a cell and 2 K+ ions into the cell
sodium-potassium pump
the process by which a cell membrane surrounds a particle and encloses the particle in a vesicle to bring the large particle into the cell
endocytosis
a small cavity or sac that contains materials and moves them around; "vehicle pod"; made up of lipid layer
vesicle
the process in endocytosis by which a cell takes in extracellular fluids; "cell drinking"
pinocytosis
the process in endocytosis by which a cell engulfs large particles or whole cells, either as a defense mechanism or as a means to obtain food; "cell eating"
phagocytosis
a cell that ingests and destroys foreign matter of microorganisms; ex. amoeba
phagocyte
the process by which a substance is released from the cell through a vesicle that transports the substance to the cell surface and then fuses with the membrane to let the substance out
exocytosis
animal cell shrinking; shriveling of the cell due to water leaving the cell
crenation
3 steps of facilitated diffusion carrier protein
bind to molecule, change shape to push through, release molecule on other side of membrane
carrier proteins that serve in active transport; pushes things across the membrane from low to high concentration
cell membrane pumps
An active transport protein in a cell membrane that uses ATP to transport hydrogen ions out of a cell against their concentration gradient, generating a membrane potential in the process; ex. light reaction in photosynthesis or ETC in cellular respiration
proton pump
4 examples of passive transport
diffusion, osmosis, facilitated diffusion, ion channels
4 examples of active transport
cell membrane pump, Na+ K+ pump, proton pump, vesicle transport
"diffusion will go, high to low"
diffusion jingle
the hotter the temperature, the _____ the rate of diffusion
faster
egg sitting in syrup (less solute) will ____
shrink
egg sitting in pure water (more solute) will ___
expand
how do you feel about salt or sugar or any high solute in a solution?
"it SUCKS!"
where in photosynthesis is there a proton pump?
light reaction (chloroplast thylakoid)
where in cellular respiration is there a proton pump?
ETC (mitochondria cristae)
(Refer to review chart)ACTIVE TRANSPORT requires energy input (does it need energy?)
T
FACILITATED DIFFUSION requires energy input.
F
DIFFUSION requires energy input.
F
ACTIVE TRANSPORT moves molecules against their concentration gradient.
T
FACILITATED DIFFUSION moves molecules against their concentration gradient.
F
DIFFUSION moves molecules against their concentration gradient
F
ACTIVE TRANSPORT requires a membrane protein.
T
FACILITATED DIFFUSION requires a membrane protein.
T
DIFFUSION requires a membrane protein.
F
Sodium-Potassium pump is an example of ACTIVE TRANSPORT.
T
Sodium-Potassium pump is an example of FACILITATED DIFFUSION.
F
Sodium-Potassium pump is an example of DIFFUSION.
F
Name a substance that can DIFFUSE readily across the cell membrane.
O2
Name a substance that is too large to diffuse across the cell membrane
Glucose
What prevents charged molecules (+/-) from diffusing across the cell membrane?
the hydrophobic tails of the membrane