INSANE IN
THE
MEMBRANE!
INSANE
IN THE BRAIN…
CELL MEMBRANES
*Surrounds cell
*Plants and animals have them
*Bouncer of the cell – decides what
goes in or out
*Looks smooth….actually made of
gaps that particles can move
through!!
MORE ON MEMBRANES
*PERMEABILITY – ability of particles to move through a
membrane
***Let’s draw some lines!!
*Non-permeable – nothing through – tough bouncer
*Semi-permeable – certain things get through (in and out) –
bouncer takes bribes…
*Permeable – everything through (in and out) – bouncer is on
break
LOOK AT YOUR LINES
Which is non-permeable? How do you know?
Which is semi-permeable? How do you know?
Which is permeable? How do you know?
----So what are cell membranes??-----
CELL MEMBRANES
*Are SEMI-PERMEABLE – only certain things getting through
*How do they get through???
QUESTION….
Which is easier – going uphill or downhill?
QUESTION…
Which is harder – walking through a crowded or empty
hallway?
QUESTION…
Which do you choose – the automatic or the one requiring
effort?
TRANSPORT!
*Particles moving ALL THE TIME!!
-Bumping, hitting, bouncing, CONSTANT
*TRANSPORT required for movement through cell
membranes
-2 types – Active and Passive
*Active Transport – requires energy
-Crowded hall, push door, uphill
*Passive Transport – does not require energy!
-Empty hall, automatic door, down hill
LET’S REVIEW THIS…
*Cell membranes are semipermeable
*Particles move in and out –
TRANSPORT
*Active Transport – requires
ENERGY!
*Passive Transport – lazy version –
NO ENERGY!
SO IN OR OUT? WHERE DO
THE PARTICLES GO??
*Particles are CONSTANTLY moving
*Want EQUILIBRIUM = even numbers on both sides; a state
of rest or balance
-Once reached, particles still partying!
*Smell this…
*DIFFUSION – movement of particles from areas of high
concentration to low concentration
*Concert ends
*Hallway when bell rings
*Smell of cookies baking!
*Let’s try it!!
EXIT TICKET
Look at the demonstration.
On a sheet of paper,
describe what is
happening.
1.22.13 REVIEW
1. What is the difference between
active and passive transport?
2. Transport describes particle
movement. What are the particles
(proteins, lipids, water molecules)
moving through?
LETS SEE HOW
OSMOSIS WORKS!!!
http://highered.mcgraw
hill.com/sites/0072495
855/student_view0/cha
pter2/animation__how_
osmosis_works.html
LET’S TAKE THIS ONE
MORE STEP…
*Diffusion moves particles high to low concentration…ALL
PARTICLES
*OSMOSIS – diffusion of WATER through cell membranes
(semi-permeable)
-So important – has it’s own name!!
-FOCUS is WATER!!
*Wants equilibrium, moves to achieve it!
HOW DO WE KNOW THE
DIRECTION OF MOVEMENT?
*Osmosis and Diffusion move from HIGH concentrations to
LOW concentrations
*Concentration is the proportion (ratio) of a molecule or
particle in a certain solution – high or low
*Let’s make a visual of PURE water, a solution with LOW
CONCENTRATION, and a solution with HIGH
CONCENTRATION of water.
REWIND…
*How do active and passive transport fit into all of this?
*Transport is the movement of particles – including water!!
*Active and passive transport refer to SMALL PARTICLES
(sugar, water)
-Passive requires no energy and moves from a HIGH
concentration to a LOW concentration
-Active requires energy and moves from a LOW
concentration to a HIGH concentration
*So which type of transport is OSMOSIS????
LET’S REVIEW…
-Membranes are SEMI-PERMEABLE – stuff goes in and
out...if allowed
-This TRANSPORT is either passive (no energy) or active
(requires energy) for SMALL particles
*Passive – HIGH to LOW
*Active – LOW to HIGH
-Particles want EQUILIBRIUM, and find it through DIFFUSION
*HIGH concentration to LOW concentration
-OSMOSIS is diffusion of water through cell membranes
*HIGH concentration to LOW concentration
ONE MORE ITEM…
*Active and Passive Transport refer to SMALL PARTICLES
*Large particles (proteins) move in and out in a different way
*Endocytosis(entrance): process by which a cell membrane
surrounds a large particle, encloses it in a vesicle, and brings it
into the cell
*Exocytosis(exit): process by which a cell releases a large particle
by enclosing it in a vesicle, moving it to the surface, then fusing
with the membrane
*****Both refer to movement of LARGE particles and are forms of
active transport!!*******
YOUR JOB
*Illustrate endocytosis and exocytosis!
-Do this in your notes
*Use textbook pages 80 and 81
-Copy diagrams provided
-Add your own style if you like!!
ROUND 1
1. What is the movement of particles from high
concentration to low concentration?
2. Which type of transport requires energy?
3. What is the diffusion of water through cell
membranes?
4. Define passive transport.
5. Define equilibrium.
6. What does it mean to be semi-permeable?
ROUND 2
1. Which type of transport is osmosis?
2. Give a real world example of diffusion.
3. How are osmosis and diffusion
connected?
4. What is the difference between active
and passive transport (energy and
concentration)?
5. What do all particles crave and work to
achieve?
6. There are 36 water molecules and 48
sugar molecules in a solution. Write the
ratio of sugar to water in simplest form.
EXIT TICKET
Look at the gummy bear
in the water. In your ENB,
write your prediction
about what you think will
happen with the gummy
bear.