1. Cell Structures- 7.2
Animal Cell
Plant Cell

2. The Outer Cell
Cell membrane- a thin, flexible barrier around the cell. Cell membranes are semi-permeable, meaning that they allow certain materials in and out of the cell
Cell Wall- Thick, outer covering of plant cells, bacteria cells, fungi cells and algae cells. Cell walls provide support and protection for the cell. Made of cellulose (plants) and chitin (fungi)

3. Picture It!
Cell Membrane
Cell Wall

4. The Nucleus
Scottish botanist Robert Brown first identified the nucleus in 1831
The nucleus controls much of the cell’s activity and contains the cell’s hereditary information in the form of DNA (Deoxyribonucleic Acid)
Almost all eukaryotic cells including plant and animal cells contain a nucleus
Prokaryotic cells like bacteria have no nucleus

5. The Nucleus, Cont. An Actual Nucleus Model of a Nucleus
“Matrix” Nucleus

6. Inside the Nucleus
Chromatin- the granular material inside the nucleus. It is made of DNA bound to protein, and carries the hereditary information in the cell
Chromosomes- chromatin condenses to form chromosomes during cell division
Nucleolus- Small dense region inside the nucleus that is responsible for the assembly of ribosomes, which make proteins
Nuclear membrane- outer covering of the nucleus, allows a steady stream of RNA in and out.

7. Chromatin
Nucleolus
Chromosomes

8. Cytoskeleton
Network of protein filaments that helps the cell maintain its shape
Also involved in many forms of cellular movement
Microtubules are hollow protein tubes that maintain cellular shape and serve as “tracks” on which organelles can travel
Microfilaments- protein filaments that provide structure for the cell

9. Organelles in the Cytoplasm
The cytoplasm is the liquid “goo” like material inside the cell. It is made of water and salts, and contains all the cell organelles (little organs)
Ribosomes are made of RNA and protein. They assemble proteins following the coded information stored in the nucleus.
Electron Microscope image of Ribosomes

10. Endoplasmic Reticulum
Internal membrane system in which cell membrane components are made and proteins are modified
Smooth ER- does not contain ribosomes
Rough ER- “studded” with ribosomes
Smooth ER
Rough ER

11. More Cytoplasmic Organelles
Golgi Apparatus- packages and ships materials, attachs necessary carbohydrates and lipids to proteins. This organelle is a stack of sac-like membranes
Lysosomes- breaks down carbohydrates and lipids, also “eats” dead organelles- cleans up the cell
Vacuoles- store food and water for cells to use, plant cells have huge organelles

12. Can you find the vacuole?

13. Energy! Energy! Energy!
Mitochondria- Found in both animal and plant cells. Breaks down glucose (food) to release energy
Chloroplasts- Found in plant, algae and some bacteria cells. Autotrophic, the organelle that converts sunlight into glucose

14. Putting it All Together

15. An Amazing Journey
Tiny little cells are so very complex! Imagine taking a magic journey inside one of your cells… what would you see????

16. Movement Through the Membrane
Section 7.3
Movement Through the Membrane

17. Cell Membrane
The cell membrane is the flexible outer covering found on the outside of cells
It regulates what enters and leaves the cell and also provides protection and support
Cell membranes allow food and water in and gases and wastes out
They are semi-permeable, which means that some things are allowed through, and others are not

18. Cell Membrane, Cont.
The core of the cell membrane is a lipid bi-layer (a double layer of lipids)
Proteins act as channels through the membrane
Carbohydrate chains are there for cell identification

19. Diffusion
Every cell is in a liquid environment– with a liquid interior and surrounded by liquid. The cell membrane separates these two liquid environments.
Concentration of a solution is the mass of the solute that is dissolved in a certain volume of solvent
In a solution, molecules move constantly. Across a membrane, they move from a high to a low concentration. This is called diffusion

20. Diffusion, Cont.
Diffusion causes many substances to move across the cell membrane, but it does not require energy
Diffusion happens automatically, when there is a concentration difference or the solutions are in equilibrium (equal concentrations on both sides)
In equilibrium, however, the molecules move rapidly in both directions

21. Osmosis Osmosis is diffusion, but not all diffusion is osmosis.
Osmosis is the movement of water across a semi-permeable membrane
Water moves from an area of high water to an area of low water concentrations
When equilibrium is reached, it moves in both directions

22. Osmotic Pressure
Osmosis exerts pressure on a certain side of the cell membrane
HyPERtonic- Area of high concentrations of particles such as salt or sugar (high PERticles)
HypOtonic- Area of high concentration of water (high H2O-- hypOtonic)
Isotonic- concentrations of particles and water are equal

23. Solution Types
If you place a cell (like an egg) in a high- particle solution (Hypertonic) then water will rush out of the egg and the egg will shrivel
In a Hypotonic (High water) solution, water will rush into the egg and the egg will swell
In a Isotonic solution, no change will be noticed because the water will move in both directions, in and out of the egg

24. Facilitated Diffusion
The word facilitate means to “assist” or to “help”
In facilitated diffusion, proteins that are embedded in the membrane help bigger molecules go through by acting as a channel
There must be a concentration difference, meaning this will not take place in equilibrium
Extra energy is not needed

25. Active Transport “Active” implies that you need energy
This is transport that needs energy in order to take place
Endocytosis- food is taken into a cell– Phagocytosis is a type of this, it is literally “cell eating”
Exocytosis is the exit of materials out of a cell– usually waste

26. Define Vocabulary 7.3 and 7.4 on page 196
Homework
Define Vocabulary 7.3 and 7.4 on page 196
Due Tuesday
Also: Progress Report