Terms in this set (20)
Main function of a cell membrane
Controls what goes in and out of cell; helps keep the cell stable
Three components of animal cell membrane
Phospholipids, proteins, cholesterol
Peripheral, integral, and transmembrane proteins
Peripheral - bound to inside layer of the cell membrane
Integral - Embedded in hydrophobic tails
Transmembrane - integral proteins that go all the way through the membrane
What are glycoproteins? Glycolipids?
Glycoproteins - protein with a piece of carbohydrate attached
Glycolipids - lipid with carbohydrate attached
Explain how nonpolar, polar, and ionic molecules cross the cell membrane
Nonpolar / hydrophobic - go straight through the phospholipid bilayer w/ simple diffusion
Polar / hydrophilic - facilitated diffusion with a transport protein
Ionic / hydrophilic - also uses transport protein
What is selective permeability?
When a cell lets some things across the cell membrane but excludes others
What is a concentration gradient? Electrochemical gradient?
Concentration gradient - difference in concentration of a substance from one area to another
Electrochemical gradient - difference in charge AND difference in concentration across the cell membrane
What is dynamic equilibrium?
When concentration on both sides of the cell membrane is equal, with no net movement, but the substances move in an equal amount
How does water cross the cell membrane?
Water goes through a transport protein using facilitated diffusion known as osmosis
What is osmosis?
When water goes from a high to low concentration across a selectively permeable membrane through an aquaporin protein channel
Compare and contrast simple diffusion, facilitated diffusion, and active transport
Simple diffusion - moves things from high to low, no energy required, doesn't require a protein
Facilitated diffusion - moves things from high to low, no energy required, requires a protein
Active transport - moves things from low to high, needs energy (ATP), needs a protein known as an electrogenic pump
Compare and contrast hypertonic, isotonic, and hypotonic solutions
Hypertonic - Solute concentration is GREATER outside than it is inside (not good for any cells), cell shrinks or shrivels, water becomes plasmolyzed
Isotonic - Solute concentration outside EQUALS the inside, no net movement, ANIMALS LIKE THIS
Hypotonic - Solute concentration is GREATER inside than it is outside, water enters the cell and it gets largers, PLANTS LIKE THIS and animals don't because they'll explode
Explain plasmolysis, turgid, flaccid, and lyse
Plasmolysis - When a cell loses water, the cell membrane falls away from the cell wall the plant wilts, eventually dies
Turgid - Cell gains water and becomes bigger, makes the cell membrane push against cell wall in plants creating osmotic pressure
Flaccid - in plant cells, when wilting would start, needs more water
Lyse - In animal cells, when water enters the cell and causes the cell to burst
Identify the ideal environments for plant and animal cells
Plant - hypotonic
Animal - isotonic
Explain the sodium-potassium pump
Type of active transport system that moves three sodium (Na) molecules outside the cell and brings two potassiums (K) in through a protein
In animals, this creates an electrochemical gradient - the outside of a cell is positive while the inside is slightly negative
Plants have this with the proton pump, when the protein pumps hydrogen atoms out in order to bring both hydrogen and sucrose back in
When protein moves two substances in or out at once
Identify three types of passive transport
Simple diffusion, facilitated diffusion, and osmosis
Compare and contrast the following bulk transport mechanisms: exocytosis and endocytosis
Exocytosis - when large molecules like food leave the cell membrane using a vesicle
Endocytosis - Bringing big molecules in with a vesicle as well
Compare and contrast phagocytosis and pinocytosis
Phagocytosis - cell engulfs particle in a vacuole, cell "eating"
Pinocytosis - cell engulfs a liquid, cell "drinking"
Four functions of membrane proteins
Transporting things across the cell membrane
Act as enzymes - speed up chemical reactions
Involved in signal trasnduction