Cell Transport Flashcards
Every living cell exists in a _____ environment
liquid
Cytoplasm is a ____
solution
Gas and liquids are called ____
fluids
In all solutions solute particles…
move constantly, collide with each other, and spread out randomly
Diffusion
particles that move from an area that they re not concentrated in to an area that they are not
What is the driving force of movement of substances across the cell membrane?
diffusion
In diffusion substances move ___ their concentration gradient
down
Example of diffusion
When you put sugar in cawfee, the sugar crystals disperse through it
Diffusion causes particles to move in and out of the cell membrane until they…
reach equilibrium
Dynamic Equilibrium
the idea that particles will still randomly move when the reach equilibrium (NO energy is needed)
How many types of diffusion are there? and what are they?
Three: Passive transport, facilitated diffusion, osmosis
Passive Transport
the movement of materials across the cell membrane without using cellular energy
In Passive transport, particles move _____ their concentration gradient. (substance moves from area of ___ concentration to an area of ____ concentration.)
down; higher; lower
What molecules can pass through the cell membrane with passive transport?
small and nonpolar (uncharged) molecules such as oxygen or carbon dioxide because their properties allow them to dissolve in the lipid’s environment
Facilitated Diffusion
the process in which molecules that cannot directly diffuse across the membrane (such as glucose and ions) pass through SPECIAL PROTEIN CHANNELS
Does facilitated diffusion require energy?
No
In facilitated diffusion substances move _____ their concentration gradient
down
Special protein channels aka…
Gated channels (which need hormones to open)
Osmosis
the facilitated diffusion of water molecules NOT solute molecules (look at example in notebook)
Aquaporins
water channel proteins needed because the lipid bilayer is hydrophobic (these are always open)
Isotonic
When equilibrium is reached with the amount of solute and water molecules “same strength”
Hypertonic
“above strength” higher concentration of solute; therefore, less water
Hypotonic
“below strength” lower concentration of the solute; therefore, more water
Hypotonic, Isotonic, and Hypertonic are all
relative terms
If the solution is isotonic an animal cell will be
normally shaped; function properly (look at nb example)
If the solution is isotonic a plant cell will be
flacid; weak b/c less water in central vacuole (look at nb example)
If solution is hypertonic in a plan tcell, the cells will
plasmolyze; die b/c central vacuole no longer supports cell wall(look at nb example)
If solution is hypertonic in an animal cell, the cells will
shrink; start to die(look at nb example)
If solution is hypotonic in an animal cell, the cells will
swell; burst and die (look at nb example)
If solution is hypotonic in a plant cell, the cells will
be healthy; normal; turgid b/c large central vacuole fully supports the cell wall (look at nb example)
Plasmolysis
cell membrane separates from cell wall due to not enough water in the central vacuole
Osmotic Pressure
the force that moves water in or out of cells
Because cells contain salts, sugars, proteins, etc. they are almost always ____ to fresh water
hypertonic
Because most cells are usually hypertonic to fresh water….
fresh water will go inside the cell, causing it to swell which can cause cells to burst
Are cells in large organisms in danger of bursting? Why?
Np, because they are surrounded by isotonic fluid such as blood
If plant cells come in contact with too much fresh water…
they may damage cell walls because of too much water in the central vacuole
If cells such as eggs come in contact with too much fresh water…
nothing will happen to them because they have no water channels
If bacteria cells come in contact with too much fresh water
nothing will happen to them because they have protective cell walls
Active Transport
the movement of materials against a concentration difference which requires energy
How many methods of active transport are there and what are they?
4: Protein pumps/molecular transport, bulk transport, endocytosis, and exocytosis
Where are protein pumps found
in the cell membrane
What do protein pumps transport?
Small molecules and ions (calcium, potassium, sodium, etc)
Why is energy needed for protein pumps?
Energy usage allows protein pumps to work because they work against diffusion by concentrating substances in a certain location.
Bulk Transport
process in which large molecules and solid clumps of material are transported by movements of the cell membrane
Endocytosis
process of taking material INTO the cell by means of infoldings,or pockets of the cell membrane
How does endocytosis occur?
1) A pocket breaks lose from outer portion of the cell membrane and forms a vesicle WITHIN the cytoplasm
2) Vesicle transports material in the cell.
(Look at model in NB)
What can endocytosis transport
clumps of food, molecules, whole cells, etc.
How many types of endocytosis are there?
2: phagocytosis and pinocytosis
Phagocytosis
type of endocytosis in which extensions of cytoplasm surround particles and package in a vacuole and engulf it (Look at model in NB)
Phagocytosis is aka
Cellular Eating
What uses Phagocytosis?
white blood cells
Pinocytosis
type of endocytosis in which pockets form along the cell membrane, fill with liquid, and pinch off the side to form vacuoles (look at model in NB)
Pinocytosis is aka
cellular drinking
Exocytosis
the process in which cells release large amounts of material
How does exocytosis occur?
the membrane of a vacuole fuses with the cell membrane, forcing the contents out of the cell
(Look at model in NB)
How do gated channels in protein pumps open?
Hormones bond to a hormone bonding site on the channels, opening the channel
What type of cell transport would be best to move substances into out out of the cell quickly?
Active Transport
Electrochemical gradient
inside of the cell is negative and the outside of the cell is positive –> so more negatively charged things want to go in and positively charged things want to go out
What is the electrochemical gradient useful for
animals and plants use it to pump out ions and create an energy differential so the cell is always doing work
electrical force
force created by membrane potential
Chemical force
concentration gradient
How many types of gated channels are there and what are they
2: volted gated ion and mechanical
Volted gated ion channels
when there’s a diff concetration between two sides of the membrane and this causes stuff to go through
Mechanical channel
signal receptor channels
Are cells always doing work
yes
Electrogenic pump
pumps that maintain the membrane potential and pump ions in out *** watch video
examples of electrogenic pumps
Na+, K+, and H+ pumps **watch video
Na+ and K+ pumps
pumps that pump 3 Na+ out and 1 K+ in
H+
pump protons out
Cotransport
pump substrates against their concentration gradient by pumping an initial substrate through the membrane and then have it simple diffuse through the membrane so that it can bring another substance with it against its concentration gradient
** watch video
Autophagy
when a cell recycles its own organelles (break + build) so they are like young
How does cotransport work
1) ATP actively transports a substrate into the cell
2) the substrate goes back out through simple diffusion
3) the substrate comes into the cell with another substrate that goes against its concentration diff
Receptor mediated endocytosis
when there’s not a lot of substance you want so the receptors that are on the cell membrane take it and bind and then form a vesicle
Autophagy
when a cell recycles its organelles (break + build) so its always like young
Ligand
any substance that binds to a receptor
Coated pits
the fuzzy thing outside vesicle for R-H endocytosis which tells cell HEY you should have this
Why is receptor mediated endocytosis done
done bc waste of energy yto do the other one
