Osmosis and Diffusion Chapter 7 Section 3

Chapter 7 Section 3

Cell Membrane The cell membrane regulates what enters and leaves the cell to maintain homeostasis also provides protection and support Composition: double-layered sheet (lipid bilayer) Flexible

Cell Membrane Semi-permeable May contain protein molecules that are embedded in the lipid bilayer which form channels and pumps to move larger material across the cell membrane Carbohydrate molecules are attached to many of these proteins (“the claw”) and act as chemical identification cards

Passive Transport Diffusion “Down a Slide” Move from high to low More concentrated to less concentrated until reaches equilibrium in the absence of other influences Does NOT require energy

Passive Transport Simple Diffusion diffusion across a membrane Facilitated Diffusion Diffusion of particle that are too large to pass through membrane are assisted by proteins to get from one side to another (channel or carrier proteins)

Diffusion of Particles

Osmosis Diffusion of water across a selectively permeable membrane No energy required because moving from an area of high concentration to low concentration Salt Sucks

Hypotonic Solutions “HIPPO” Solute concentration OUTSIDE cell is LOWER (below strength) than INSIDE the cell (meaning that MORE salt is INSIDE the cell) Remember SALT SUCKS!!!! Water moves INTO the cell causing it to SWELL Cytolysis – animal cells bursting because too much water

Hypotonic Solutions “HIPPO”

Hypertonic Solutions “HYPER” Solute concentration OUTSIDE cell is HIGHER (above strength) than INSIDE the cell (meaning that MORE salt is OUTSIDE the cell) Remember SALT SUCKS!!!! Water moves OUT of the cell causing it to SHRIVEL

Hypertonic Solutions “HYPER”

Isotonic Solutions “I SO HAPPY” EQUAL solute concentrations inside and outside of cell water diffuses in and out of cell at equal rates so cell stays the same

Isotonic Solutions “I SO HAPPY”

The Effects of Osmosis on Cells

Involves moving molecules “uphill” against the concentration gradient Active Transport Involves moving molecules “uphill” against the concentration gradient Going up the slide Requires energy May cause protein channel to Change shape http://www.diffen.com/difference/Active_Transport_vs_Passive_Transport

Active Transport

Active Transport continued…(Endocytosis) “pac-man” Cell membrane encloses particle forms a pouch (vesicle) and pinches off into cell Pinocytosis (solutes/fluids) Phagocytosis (large solid particles)

Active Transport continued….(Endocytosis)

Active Transport continued….(Exocytosis) Pushing substances out of the cell, such as the removal of waste Think of a zit and popping it

Active Transport continued….(Exocytosis)

Describe the specialization of cells in your own words.

Cell Specialization Chapter 7 Section 4 Cells develop in different ways to perform different tasks Just like doctors specialize in a certain field of study

4 levels of organization 1. individual cells 2. tissues – group of similar cells working together to perform a particular function Muscle Epithelial Nervous Connective

4 levels of organization 3. organs – group of tissues working together to perform a specific function 4. organ systems – group of organs working together to perform a specific function