Section 7-3
MOVEMENT THROUGH THE MEMBRANE
The Cell Membrane
Function: ______________________________________________
____________________________________________________________
Selective permeability: ___________________________________
____________________________________________________________
Structure
Phospholipid Bilayer (Fluid Mosaic Model):
______________________________________________________
____________________________________________________________
• Polar Head
– _______________________
_______________________
_________________________
• Lipid Tails
– _______________________
_______________________
__________________________
Why is the lipid bilayer important?
•
•
•
_____________, ____________ structure
Strong barrier between the _______ and its __________________
Allows only certain ______________ in or out at certain ________
– Ex: __________________
__________________
____________________
____________________
____________________
Other membrane structures
Protein molecules
Form channels and pumps that help to move material across the
membrane
•
Carbohydrate molecules
– Act like _________________ for the cell
– Basis for blood typing: the antigens on the blood cells (A, B, AB) are
______________________ chains
Cell recognition protein
• Foreign carbohydrate chains are why transplanted tissue is
often rejected by the body
Diffusion
Definition: The movement of molecules from an area of
___________concentration to an area of _______ concentration,
until equilibrium is reached.
Equilibrium _________________________________________
What causes diffusion?
• Diffusion is caused by the ________________________________
___________________________________________________________________
More molecules = ____________________
• The collisions cause the molecules to ______________________.
• Examples: _________________________________________________
Diffusion in Cells
Molecules are able to diffuse through the _________________ and
allow the cell to _______________.
Facilitated Diffusion – ____________________________________
_____________________________________________________________________
Osmosis (A special kind of diffusion)
Osmosis is the diffusion of __________ molecules through a _____
________________________.
Selectively permeable? ______________________________________
1. Isotonic – ___________________________________________________
2. Hypertonic – _________________________________________________
3. Hypotonic – __________________________________________________
Moving down a concentration gradient is like riding a bike down a
hill. _________________________________
Osmosis and diffusion are examples of ___________________!
Active Transport
Moving up a concentration gradient is like riding up a hill.
______________________________.
• Active Transport: ______________________________________________
___________________________________________________________________
• Molecules move from ______ concentration to _________ concentration.
• Proteins use _______ to pump ions and small molecules _______
concentration gradient.
Types of Active Transport
1. Endocytosis – the process of taking material into the cell by
means of infoldings of the cell membrane.
Phagocytosis – ____________________________________________
________________________________________________________________
– Pinocytosis – ______________________________________________
________________________________________________________________
2. Exocytosis
– Large molecules move from ___________________________________
– Contractile Vacoule – _________________________________________
_________________________________________________________________
7-4: Specialized Cells
•Cells with a specific ________________________ and are found in
__________________ organisms.
•We have ______________________________________________
Tissue
• Definition: ____________________________________________
• Examples: ___________________________________________
Organs
• Definition: ____________________________________________
Organ Systems
•
Definition: __________________________________________