cell membranes are composed of 2 layers of phospholipids = phospholipid bilayer 2 layers of...
TRANSCRIPT
Cell Membranes are composed of 2 Layers of Phospholipids = Phospholipid Bilayer
• 2 layers of phospholipids• Heads = love water• Tails = hate water• Middle = oily
substance that keeps water out
What enters and exits cells?
• Water Small molecules can pass through the phospholipid bilayer; but how
do the big molecules get into
cells?
•Oxygen
•Carbon Dioxide
•Glucose
http://www.teachersdomain.org/asset/tdc02_int_membraneweb/
•Enzymes
The Fluid Mosaic Model of The Cell Membrane
• Fluid: moves easily• Mosaic: made of phospholipids,
carbohydrates, protein channels
Cell Transport Jigsaw:• Each group will read about a
different type of cell transport• You are to become an
EXPERT in your topic.
• While reading:• Pull out vocab words and
define. • Take notes on important info.• Summarize the transport
type.
• You will then switch groups and become the teacher of that topic in your group.• You are fully responsible for
the people in your group learning your section of notes.
• Group 1: Diffusion
• Group 2: Osmosis
• Group 3: Facilitated Diffusion/Ion Channels
• Group 4: Sodium Pumps
• Group 5: Exo/Endocytosis
• **B2 Only:• Group 5:Exocytosis• Group 6: Endocytosis
Terms given for the movement of molecules into and out of the cell:
Passive Transport: No Energy Required• Simple Diffusion• Osmosis• Facilitated Diffusion
Active Transport: Energy (ATP) Required• Cell Membrane Pumps• Endocytosis• Exocytosis
Passive Transport: Simple Diffusion
Movement of particles from
HIGH CONCENTRATION LOW CONCENTRATION
until EQUILIBRIUM is reached. (what is equilibrium?)
Demos: Food Coloring and Perfume
What will happen?
The molecules continue to move from areas of high concentration to low concentration until
EQUILIBRIUM is reached!
= oxygen
Passive Transport: Facilitated Diffusion
• Diffusion of molecules that are too large• Need the help of protein channels• Example: Glucose
Passive Transport: OsmosisMovement of WATER from
HIGH CONCENTRATION LOW CONCENTRATION (through a protein channel)
until EQUILIBRIUM is reached
* osmosis = facilitated diffusion of water because of oily center of cell membrane
What will happen? = water
Higher concentration of
solute inside the cell than outside the cell
Lower concentration of solute inside the
cell than outside the cell
Equal concentration of solute inside and
outside the cell
= solute
Why does the water move,
not the molecules in
osmosis?
Active Transport: Cell Membrane Pumps
• The movement of particles from low to high concentration with the help of a protein pump. Requires Energy (ATP)!