Cell Boundaries
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Transcript of Cell Boundaries
HONORS BIOLOGY
Cell Boundaries
Cell Membranes
1. One of the most important functions of a cell membrane is:
to regulate the movement of molecules into and out of a cell
2. A cell membrane is said to be __________________________• Which means only specific
kinds of molecules can get through the membrane
• Another word for it is ______________________Semipermeable
Selectively Permeable
3. Selectively Permeable
Cell membranes let some molecules enter a cell, but prevents other molecules from getting in.
Can Enter Can Not Enter- Water- Small Molecules (O2 & CO2)
- Non-polar lipids
- Macromolecules- Ions (Na+,Cl-) - Hydrophilic molecules (glucose)
5. Concentration
The concentration of a solution is:
The mass of the SOLUTE divided by the volume of the SOLUTION
For example: 10g/1L
The more solute per volume equals a greater concentration.
6. Diffusion
The movement of molecules from an area of high concentration to an area of lower concentration
Example of Diffusion:
Beaker of water. Add salt to the water.Will all of the water be salty or just the side of
the beaker that you dumped the salt into? When you add salt the salt will diffuse to all of
the water.
Example of Diffusion:
The smell of popcorn after it’s been popped.
Does the smell of popcorn stay where the popcorn was popped? Why or why not?
Diffusion
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_diffusion_works.html
Osmosis
The diffusion of water. The movement of water from a high water concentration to a low water concentration.
Osmosis
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_osmosis_works.html
HypotonicSolution has a lower solute concentration than the
cellWater enters the cell, animal cells can expand and
possibly burst.
IsotonicThe concentration of the solutes is the same inside and outside the cell
HypertonicSolution has a higher solute concentration
than the cellWater leaves the cell, animal cells can shrink.
Facilitated Diffusion
The movement of specific molecules across cell membranes through protein channels.
Facilitated Diffusion
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_facilitated_diffusion_works.html
Active Transport
Energy requiring process that moves material across a cell membrane against a concentration difference.
Active Transport
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_the_sodium_potassium_pump_works.html
Overview
Endocytosis: Taking material in to the cell through cell membrane pocketsPhagocytosis: Solids or large molecules movedPinocytosis: Liquids moved
Exocytosis: Releasing material from the cell