solutions/cell transport Flashcards
what re the 2 major components of the cell membrane?
- phospholipid molecules
2. proteins
what are phospholipids in the structure of the cell membrane, what are the parts?
- double layer of molecules that make up cell membrane
- hydrophilic heads –> polar, group together on the outside layers (bread of a sandwich)
- hydrophobic tails –> non-polar, group together on the inside (fillings of a sandwich), double layer
what is a concentration?
the amount of solute in a solvent
what is a concentration gradient?
different concentrations of solute (one high, one low), typically separated by a membrane
what is a solute?
the component that is dissolved in the concentration
what is a solvent?
the liquid component
eg. often water
what is a solution?
a solute in a solvent
what is diffusion?
Movement of particles from an area of high concentration to an area of low concentration
-movement of solutes
what are factors that determine diffusion?
- charge of molecules
- structure
- size
- concentration of gradient
what is passive transport?
- movement of particles down a concentration gradient
2. requires no input of energy –> passive process
what do solute concentrations always want to be in?
equilibrium
what is simple diffusion, what materials diffuse by simple diffusion?
when substances diffuse down their own concentration gradient through the cell membrane
NOTHING HYDROPHILIC, NOTHING LARGE, NOTHING CHARGED
-lipid-soluble compounds
-dissolved gases
eg. oxygen, CO2
what is facilitated diffusion, what materials are moved by facilitated diffusion?
when substances diffuse down their own concentration gradient but proteins are needed to help facilitate movement through cell membrane
-moves molecules that are large, bulky, charged
what are the 2 types of diffusion?
- channel-mediated facilitated diffusion
2. carrier-mediated facilitated diffusion
what do channel proteins transport across the cell membrane?
water soluble compounds and ions
what do carrier proteins transport across the cell membrane?
molecules that are too large to fit through channel proteins
eg. glucose, amino acids
what is an aquaporin?
a channel protein that specifically facilitates movement of water –> osmosis, can move large amounts of water
what is osmosis?
movement of water through a semi permeable membrane.
-occurs when membrane is permeable to water, but not to solutes
which way does water move across a gradient?
movement of water from:
side with high water concentration –> side with low water concentration
movement of water from:
side with low solute concentration –> side with high solute concentration
“water always wants to be where there is more solute”
what is the hypertonic solution?
is the solution with the higher solute concentration
what is the hypotonic solution?
is the solution with the lower solute concentration
what are isotonic solutions?
when both solutions have the same solute concentration, regardless of volume
what will happen to an animal cell if it is put in a hypotonic solution, what is this called?
placed in a hypotonic solution, water will move into the cell (water movement from area of low solute to high solute), which will cause the cell to expand and burst. this is called lysis “lysing the cell”
what will happen to an animal cell if it is put in a hypertonic solution, what is this called?
placed in a hypertonic solution, water will move out of the cell (water movement from area of low solute to higher solute), which will cause the cell to shrivel. this is called crenation
what will happen to an animal cell if it is placed in an isotonic solution?
nothing, but water will still move by random diffusion
what will happen to a plant cell if placed in a hypotonic solution, what is this called?
placed in a hypotonic solution, water will move into the cell (water movement from low solute to higher solute), which will cause the cell to become turgid.
- this is a plants happy place
- will not burst because it has a cell wall to hold it together
what will happen to a plant cell is it is placed in a hypertonic solution, what is this called?
placed in a hypertonic solution water will move out of the cell (water movement from low solute to higher solute), and cause the cell membrane to pull away from the cell wall. this process is called plasmoysis.
“the cell has plasmolyzed”
what will happen to a plant cell that is placed in an isotonic solution?
plant will lose turgor pressure and will become “flaccid”. no increase in water movement into plant cells, will cause the cells to not be firm (turgid), which effects structural support, and will cause the plant to wilt.
what is active transport?
- movement of particles against concentration gradient
“making a gradient” - uses energy
cell wants to be in equilibrium, so you need energy to force particles the opposite way they want to go - needs carrier proteins
“pump”
movement of particles using energy, against the concentration gradient with a carrier protein
what is co-transport?
moving multiple things into/out of the cell at once
-cell takes advantage of solutes wanting to be in equilibrium and will pump (via active transport) ions out/in and when they return/leave, they bring an additional material with them
