1. Moving Cellular Material
Chapter 2 Lesson 3

2. unit membrane a thin structure composed of proteins and lipids
type of membrane found around all cells
around many of the structures inside cells
the outer boundary of a cell

3. Important Property of Membranes
selectively permeable: certain molecules go through them and other molecules do not

4. Selectively Permeable
Not all membranes are permeable to the same molecules.
However water, oxygen, and carbon dioxide are small and easily passes through most membranes.

5. How does a substance pass through a unit membrane?
Passive Transport
Active Transport
Facilitated Diffusion

6. PASSIVE TRANSPORT
the passage of substances across a membrane without the use of energy

7. PASSIVE TRANSPORT This is the main way.
Small molecules, such as oxygen and carbon dioxide, pass through membranes via passive transport.
Passive transport depends on the amount of substance on each side of a membrane.
This is the main way.

8. two main forms of passive transport
Diffusion
Osmosis

9. diffusion
the movement of molecules from an area of higher concentration to an area of lower concentration
diffusion
from Latin diffusionem, means “scatter, pour out”

10. diffusion
diffusion can be speeded up by such things as heat,movement, and pressure

11. Diffusion
Diffusion continues until the concentration of a substance is the same on both sides of the membrane. The substance is then in equilibrium.

12. the diffusion of water through a membrane
osmosis
the diffusion of water through a membrane

13. osmosis
Semipermeable cell membranes allow water to pass through them until equilibrium occurs.

14. Facilitated Diffusion
Facilitated diffusion occurs when molecules pass through a cell membrane using special proteins called transport proteins.
Carrier proteins are transport proteins that carry large molecules through the cell membrane.
Channel proteins are transport proteins that form pores through the cell membrane.

15. Facilitated Diffusion
The Plasma Membrane
11/23/2018
Facilitated Diffusion
*Is a type of passive transport
Doesn’t require energy
Uses transport proteins to move molecules from high to low concentration
Facilitated Diffusion- is the movement of larger molecules like glucose through the cell membrane  larger molecules must be “helped”
Examples: Glucose or amino acids moving from blood into a cell.
G. Podgorski, Biol. 1010

16. Facilitated Diffusion

17. ACTIVE TRANSPORT
the passage of particles through a membrane; requires the use of cellular energy
(sometimes because of the size of the molecule being so large, or going against gradient)

18. This is going to be hard work!!
Active Transport
Requires Energy.
ATP (form of energy made by mitochondria).
Moves against the concentration gradient.
High
low
This is going to be hard work!!

19. Sodium Potassium Pump What I need to know
Active transport goes AGAINST the concentration gradient
Low solute concentration to high solute concentration
The cell uses energy (ATP) to actively transport Na+ out of the cell and K+ into the cell against the concentration gradient

20. Sodium Potassium Pump

21. Endocytosis and Exocytosis is the mechanism by which very large molecules (such as food and wastes) get into and out of the cell
**ENERGY IS REQUIRED
Food is moved into the cell by Endocytosis
Wastes are moved out of the cell by Exocytosis

22. Endocytosis Think endo- Think enter
Transporting material into a cell by the in folding of a membrane.
Think endo-
Think enter
To take inside of the cell

23. 2 Types of Endocytosis
Phagocytosis- Solid particles are ingested into the cell.
Pinocytosis – liquids and very small molecules are taken into the cell.

24. Endocytosis

26. Exocytosis
Moves materials out of the cell
Think exo-
Think exit

27. Exocytosis- moving things out.
The Plasma Membrane
Moving the “Big Stuff”
11/23/2018
Exocytosis- moving things out.
Molecules are moved out of the cell by vesicles that fuse with the plasma membrane.
This is how many hormones are secreted and how nerve cells communicate with one another.
G. Podgorski, Biol. 1010