Unit 3: Cell Membrane Function Flashcards
What is the cell membrane out of?
composed of a lipid bilayer with a hydrophobic, nonpolar interior
Why is the cell membrane considered selectively permeable?
allows smaller, nonpolar molecules to pass freely, while other larger molecules require assistance.
What is passive transport?
slide through the membrane or its proteins without energy
what is active transport?
requires ATP to cross the membrane (sometimes needs proteins too) NEEDs energy bc it goes from low to high concentration = against concentration gradient
What is diffusion?
Requires no energy or proteins and goes from high to low concentration to pass through the membrane
what is facilitated diffusion?
requires a protein channel to pass from high to low concentration
What is osmosis?
type of diffusion that deals with water
What is Isotonic?
If a cell is in this solution, the concentration is equal, so the water moves equally and NOTHING happens to cell
What is Hypertonic?
If a cell is in this solution, the concentration is higher inside of the cell, so the water moves OUT, and cell SHRINKS
What is Hypotonic?
If a cell is in this solution, the concentration is lower inside of the cell, so the water moves IN, and cell SWELLS
What does vesicle transport mean?
cells can envelope materials into a section of the cell membrane, encircle or pinch them
What is endocytosis?
endo means “within”
cells can bring a large amount of substances into a cell by enveloping the contents then pinching them off
what is exocytosis?
exo means “exit”
cell export large amounts of substances = sending vesicle to cell membrane then it fuses to dump its contents.
