1. Chapter 7
Section 7-3
&
Section 7-4

2. Section 7-3 Movement Through The Membranes

3. The Cell Membrane
Key Concept:
The cell membrane regulates what enters and leaves the cell and also provides protection and support

4. The Cell Membrane
The cell takes in nutrients and expels wastes plus cell products through the cell membrane
The Basic Structure Of Nearly All Cell Membranes Is The LIPID BILAYER

5. LIPID BILAYERS
Form Automatically When Certain Lipids Are Dissolved In Water
Tough Flexible Structure
Strong Barrier Between Cell Contents And Its Surroundings

6. LIPID BILAYERS

7. In Addition To The Bilayer, The Cell Membrane Contains:
Fluid Mosaic Model
In Addition To The Bilayer, The Cell Membrane Contains:
Proteins That Form
Channels & Pumps
Proteins with Carbohydrates That Form
Antigenic Sites
Communication Sites

8. Diffusion All Living Cells Contain And Are Surrounded By Liquid.
THE CELL MEMBRANE REGULATES THE MOVEMENT OF MOLECULES FROM ONE SIDE OF THE MEMBRANE TO THE OTHER

9. Is A Solution Of Many Different Substances In Water
Cytoplasm
Is A Solution Of Many Different Substances In Water

10. A liquid mixture of 2 or more substances evenly mixed.
Solution
A liquid mixture of 2 or more substances evenly mixed.
Solvent
The liquid in which the substances are mixed
Solute
Substances dissolved in the Solvent

11. Molecules Are Moving Constantly
In A Solution:
Molecules Are Moving Constantly
They Collide and Bounce off each other
This causes them to spread out randomly
Resulting In:
Movement from an area of higher concentration to an area of lower concentration

12. DIFFUSION
Molecules move away from an area of higher concentration to an area of lower Concentration
Equilibrium
Concentration of a solute is the same throughout the solution

13. Diffusion Causes Many Substances To Move Across A Cell Membrane But:
Key Concept:
Diffusion Causes Many Substances To Move Across A Cell Membrane But:
Does NOT Require The Cell
To Use Energy

14. Diffusion & Cells
Substances that can diffuse across cell membranes will do so until equilibrium is reached
Diffusion continues after equilibrium but the rates in and out are equal

15. Facilitated Diffusion
Molecules that can easily diffuse across the cell membrane:
Alcohol
Water
Small Lipids

16. Facilitated Diffusion
Other molecules can not pass through the cell membrane but still get into the cell.
HOW?

17. Facilitated Diffusion
Through Protein Channels in the Cell Membrane that allow a substance to cross.
Allows Diffusion In Both Directions
Each Channel Substance Specific
DOES NOT REQUIRE ENERGY

18. The Diffusion Of Water Through A Selectively Permeable Membrane
OSMOSIS
Key Concept:
The Diffusion Of Water Through A Selectively Permeable Membrane

19. Osmosis Permeable Membrane Impermeable Membrane
Substance Can Easily Cross
Impermeable Membrane
Substance Cannot Cross
Selectively Permeable Membrane
Some Substances Can Cross, Others Cannot

20. The Tonics Hypotonic Isotonic Hypertonic Less concentrated solution
Equally concentrated solution
Hypertonic
More Highly concentrated solution

21. The Tonics

22. Osmotic Pressure
Pressure exerted on the hypertonic side of a selectively permeable membrane
May cause cells to shrink or burst

23. Active Transport Moves Material Across A Cell Membrane
Against A Concentration Gradient
(from area of Lower concentration into an area of Higher concentration)

24. Active Transport
Requires Energy

25. Active Transport Endocytosis Exocytosis
Used to bring in large molecules, food, and whole cells
Exocytosis
Membrane surrounded material from inside the cell fuses with the cell membrane, releasing the contents.

26. The Diversity of Cellular Life
Section 7-4
The Diversity of Cellular Life

27. The differences in living things begins with cells:
The ways in which cells are specialized to perform certain tasks
The ways in which cells associate with one another to form multicellular organisms.

28. Unicellular Organisms
Unicellular organisms are made up of only one cell.
Bacteria and fungus, for example
Unicellular organisms dominate life on Earth.

29. Colonial Organisms
Unicellular organisms that live in groups of same species
Algae, for example
They are attached to one another
They have few specialized structures

30. Multicellular Organisms
Organisms made of many interdependent cells
Such as humans and animals
Cells are specialized
Each performs a specific role or function
Has specific form

31. Levels of Organization
The levels of organization in a multicellular organism are:
1. Individual cells
2. Tissues
3. Organs
4. Organ systems

32. Tissues A group of similar cells that perform a particular function
Most animals have four main types of tissue:
Muscle
Epithelial: cover or line body surfaces, such as skin
Nervous
Connective Tissue: bone, blood, cartilage, and lymph

33. Organs & Organ Systems Organs = Many groups of tissues
Muscles are organs made of muscle, nerve, and connective tissue
Each tissue performs an essential function for the organs
Organ Systems = A group of organs working together to perform a specific function
There are 11 major organ systems
Include muscular, skeletal, and nervous systems