1. Cell Membrane Structure

2. Phospholipid bilayer:
a double layer of lipids makes up most of the cell membrane.
Proteins: many proteins are embedded in the phospholipid bilayer
Some act as channels to transport materials through the membrane
Some are connected to carbohydrate chains on the exterior of the cell
Carbohydrates:
Short chains of carbohydrates are connected to proteins or lipids on the exterior surface of the cell
They act as markers to identify the cell

3. Selectively Permeable
Cell membranes act as barriers, controlling which materials enter and leave the cell
Materials can enter or leave the cell based on their size and the amount of substance present(concentration)

4. Cell Transport
PassiveTransport: small molecules can cross over the cell membrane without using extra energy
Diffusion: small particles flow down a con-
centration gradient from an area of high
[concentration] to an area of [low]
Osmosis: the diffusion of water molecules over
the cell membrane
Facilitated Diffusion: particles still travel from [high] to [low], but they pass through channels in the membrane Example: ions
Raw Egg Osmosis Demonstration

6. Types of Solutions and Movement of Water
Hypertonic Solutions
Hypertonic solutions have a HIGHER concentration of solutes than what is inside the cell
This causes water to move
OUT of the cell.
Hypertonic environments shrink
animal cells.

7. Hypotonic Solution
Hypotonic solutions have a LOWER concentration of solutes than what is inside the cell
This causes water to move
INTO the cell.
Hypotonic environments
swell animal cells.

8. Isotonic Solutions Isotonic solutions have THE SAME concen-
tration of solutes as what is inside the cell
While water will move in and out,
there is no NET movement of
molecules.
Isotonic environments cause
no net change.

9. Cells in Hypotonic Solution Normal Cells in Isotonic Solution
Cells in Hypertonic Solution
Cells in Hypotonic Solution
Normal Cells in Isotonic Solution
                             
                                                          

10. Active Transport Endocytosis: endo: within cyt: cell -osis: process of
Active Transport requires additional energy, because substances are being transported AGAINST the concen- tration gradient(from [low]  [high])
Endocytosis: endo: within cyt: cell -osis: process of
the process of taking materials into a cell by
forming vesicles around the substance
pinocytosis: pin: to drink
cells taking in substances dissolved in water
phagocytosis: phag: to eat
cells taking in large particles
Exocytosis: exo- from outside
the process of removing substances from the cell by
fusing internal vesicles with the cell membrane

11. White Blood Cell Engulfing Bacteria