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Biology Chapter 3.3-3.5
Terms in this set (50)
extreme water loss (in a hypertonic environment)
cell rupture due to too much water moving in (in hypotonic environment
Which direction does water move?
from hypotonic to hypertonic
which kind of molecules can cross the cell membrane (lipid bilayer) easily?
small, non-polar molecules like O2 and CO2
what kind of substances require special protein channels to cross the cell membrane?
too large, charged, and/or polar substances like sodium (Na+), potassium (K+), glucose, and water
when substances move down their concentration gradient across the cell membrane with the help of special membrane proteins
what is the function of carbs in the cell membrane?
an identification tag; enable cells to distinguish one type of cell from another
what is the function of proteins in the cell membrane?
help materials cross membrane (protein channels), key components in cytoskeleton, support in cells
what is the function of cholesterol in the cell membrane?
strengthen the cell membrane
how does the phospholipid bilayer form?
the non-polar tails come together, and the polar heads are attracted to the water on the inside and outside of the cell
if a protein is attached to the non-polar tails of the phospholipid molecule, what is its charge?
non-polar, because it is touching a non-polar material
why is it called the Fluid Mosaic Model?
the fluid part of the name represents how the phospholipid bilayer moves and flows, and the mosaic explains how all the components come together
what three factors determine how a molecule crosses the cell membrane?
size, polarity, concentration
passive transport moves molecules ____ the gradient from ____ to ____ concentration
down, high, low
active transport moves molecules ____ the gradient from ____ to ____ concentration
up, low, high
how does active transport differ from facilitated diffusion?
AT moves molecules from lower to high concentration, FD goes from higher to lower concentration
AT requires chemical energy (ATP) from the cell, facilitated doesn't and uses kinetic energy
are molecules in constant motion?
the movement of substances across the cell membrane without the use of energy by the cell
the movement of molecules from higher to lower concentration due to kinetic energy, moving down the concentration gradient
where the concentration of a substance of equal throughout a space
diffusion of water across the membrane
why are hypertonic, hypotonic, and isotonic relative terms?
they can refer to the cell or the environment
relatively more dissolved "stuff" (less water) than what you are comparing it to
relatively less dissolved "stuff" (more water) than what you are comparing it to
equal concentration of dissolved "stuff" (and water) in all areas of comparison
weak salt solution
water uses a special protein channel called ____
Na+, Cl-, and Ca+ use special protein channels called ____
what does it mean for an ion channel to be "gated"
it needs something else to happen to open or close the channel
if a hypertonic cell is in a hypotonic environment, where is the water moving?
into the cell
if a hypotonic cell is in a hypertonic environment, where is the water moving?
out of the cell
the movement of substances across the cell membrane against the gradient, using chemical energy from the cell
active transport protein
what is the importance of the sodium-potassium pump?
to keep the electrical charge of the inside of the cell negativ, and the outside positive (important in nerve cells)
processesin which some cells move a larger amount of material in and out
solid particles, "eating" in 1 celled organisms (white blood cells)
energy of motion
what is molarity the measure of?
the concentration of a substance
which organelle makes a lot of ATP when oxygen is available?
What does ATP provide for cells?
an electrogenic pump that works largely with H+ ions in plants, fungi, and bacteria
a carrier protein that actively transports K+ ions into and Na+ ions out of animal cells
active transport examples
exocytosis, endocytosis, sodium-potassium pump
does a plant cell wall offer protection to a hypotonic environment?
yes (it doesn't burst often)