Lab Week 2 Flashcards
Cells are…?
Semipermeable
What is selectively permeable?
The cell decides what material will be allowed to cross the cell membrane and what cannot
Can cells be both semipermeable and selectively permeable?
Yes
What is dialysis tubing?
Stimulated cell membrane
Semipermeable
What is a phospholipid bilayer?
Basic molecular structure of all cell membranes
What limits what will move past the cell membrane and why?
1) size
- cell membranes have tiny holes, material that can go through are very tiny and big material cannot
- if big things want to go through they need special mechanisms
2) charge
- anything with a charge (ions) would find it difficult unless they have a special mechanism
Movement of materials through cell membranes follow what law?
Law of diffusion
What is diffusion?
Molecules and atoms that go from areas with a lot of them to areas with none or very little of them
Happens naturally
What does diffusion described as?
Concentration gradient
- goes from high to low
What is an even distribution of material?
Equilibrium (no more movement if this takes place)
What is osmosis?
An example of diffusion when water molecules going down their concentration gradient through semipermeable membranes
What are two conditions needed for osmosis?
1) water is diffusing
2) must be passing through semipermeable membrane
What is passive transport?
Osmosis and diffusion do this
When no energy is needed and it goes naturally high to low (the concentration gradient goes down)
What is active transport?
When cells move things across the membrane the opposite way, from low to high, needing energy because it is against the concentration gradient
What is diffusion and osmosis interested in?
Diffusion- solute
Osmosis- solvent
What is the osmotic pressure?
Force osmosis generates and if resisted at the same force osmosis stops
What is hypertonic?
Solution has more concentration
What is hypotonic?
Solution has less concentration
What is isotonic?
2 solutions that are equally concentrated
What is a cytosalt?
Water with stuff dissolved in it
What happens in a hypertonic environment?
Water outside the cell has a greater concentration of solutes than inside the cell
Less water outside of cell than inside
So water leaves cell to go to the less concentrated area resulting in the cell shriveling up
What happens in a hypotonic environment?
Water outside of cell has less concentration than inside the cell
More water outside the cell than inside the cell
So water keeps getting sucked into cell until it lyses
What does lyse of a cell mean?
The cell blows up because it kept sucking in water
Lysing if red blood cells is called?
Hemolysis
What happens in an isotonic environment?
The cells are happy because inside and outside the cells are equal
No movement of water
What is filtration?
Moving material through semipermeable membrane and spreading the material through size
Small particles pass while large ones do not
Always requires some time of force
What is the force used in the human body for filtration?
Blood pressure
What is calcium carbonate?
Chalk dust
What is an osometer?
Demonstrates osmosis
What is the indicator we used in the experiment that indicated starch?
Lugols solution
Or
Lugols iodine
What is semipermeable?
Some material can cross the cell membrane others cannot
