Phospholipid & Cholesterol Molecules

In class we created Fluid Mosaic posters in groups that modeled a cell membrane and how it worked. Over the next few days in class Mr. Ludwig lectured and we took notes over the models and what each part did. I did my notes in "dummy" terms so they were easy for me to understand. So, I figured I'd post them (:


Phospholipid & Cholesterol molecules

Polar head groups
Cholesterol - stiffened region
More fluid region
BASICALLY...
Phospholipid = phosphate
Tails = fatty acids

INSIDE-hydrophobic region
OUTSIDE-hydrophillic regions

Transmembrane protein = transports stuff
-ability to be lots of different things ( across whole membrane, size, shape)

WHATS IT DO?
protects - keeps things from going in or out (sort of like a cell wall)
basically its the outside of the WHOLE cell

300 (movie) - city is the cell. city makes persians come in & out.

if it is deemed harmful, the cell membrane keeps it out completely.
it chooses who it lets in & keeps out

size of the object trying to get in doesn't matter, if the cell membrane doesn't want you in YOUR OUT OF LUCK.

most important part


FUNCTIONS of membrane proteins -

*PROTEINS DO MOST JOBS

CHANNEL PROTEINS -
tubular
Allow passage of molecules through membrane
(Really specific -only let certain things in)
hollow tube
CARRIER PROTEINS -
Combine with substance to be transported
Assist passage of molecules through membrane
-latch on to them on the outside and go with them through.. carry things across.
change shape!
CELL RECOGNITION PROTEINS-
Provides unique chemical ID for cells
Help body recognize foreign substances
(Antenna like protein that recognizes different substances like bacteria or bad stuff to take a way)
RECEPTOR PROTEINS-
Binds with messenger molecule
causes cell to respond message
(wiggle your little toe)
passes signal to inside of cell -almost like someone yelling FIRE & then the other fires
ENZYMATIC PROTEINS-
carry out metabolic reactions directly
chew up & build up things


TYPES OF TRANSPORT:
Active VS Passive
Plasma membrane is differentially OR
(selectively permeable) selective, somethings get & in somethings get out.
Allows some material to pass
Inhabits passage of other materials

PASSIVE TRANSPORT:
No ATP requirement (doesn't spend energy) ATP(for now) = energy
Molecules follow concentration gradient(change)
LOTS = high concentration cell is bathes in it, inside low concentration
gradient - shift or change across a region (powerpoint- black to white)
-WORKS EASY

ACTIVE TRANSPORT-
big yucky thing trying to get in & it doesn't want it to.. bounces off (needs carrier)
need energy to get the big dude inside!
-DOESN'T WORK EASY

WATER- size of water lets it pass even thought it's sort of polar
CHARGED MOLECULES- only with channel
GLUCOSE, MACROMOLECULE - needs active transport

DIFFUSION-
a solution consists of:
a solvent (liquid), and
a solute (dissolved solid) --salt, proteins
Diffusion-
net movement of solute molecules down concentration gradient
MEANS- random motion - moving from high concentration to a low concentration (blue dye in water's movement)
water moves independent, dye moves independent

WHY DONT YOU USE DISTILLED WATER IN IV
-too much concentration of water will make cell expand.. needs more molecules

OSMOSIS-
diffusion of water down it's concentration gradient. (reverse osmosis = water treatment)
water moving across membrane
when you start dissolving particles in water - few molecules are free to be the actual concentration of water
a lot of dissolved stuff sitting in your cell
water surrounds particles to dissolve them.
salty water has a low concentration of water bcuz the water is busy dissolving the cell
put cell in salt- more solutes for the water to be attracted to.. water sees low concentration outside (waters going to gush out of cell) shrink like crazy.
almost pure water - (water follows to dissolve stuff, low concentration)

EVERYTHING GOES FROM HIGH TO LOW CONCENTRATION