1. Bell Ringer 12/1/11 What is the person on the left looking through?
What is the person on the right looking through
What point is this cartoon making?
Get ready for notes!

2. The Story of Cells

3. What are cells? The Building Blocks of Life
The cell is the smallest structural unit capable of performing life functions.

4. Cell Trivia
The average human being is composed of around 100 Trillion individual cells!!!
The egg yolk from an ostrich egg is the largest cell. They are about a half foot long.
It would take as many as 50 cells to cover the area of a dot on the letter “i”

5. Discovery of Cells
1665- English Scientist, Robert Hooke, discovered cells while looking at a thin slice of cork (bark of tree)
He described the cells as tiny boxes or a honeycomb
He thought that cells only existed in plants and fungi

6. The Microscope!
1673- Anton von Leuwenhoek, invented the microscope and observed pond scum and discovered single celled organisms
He called them “animalcules”
He also observed blood cells from fish, birds, frogs, dogs, and humans
Therefore, it was known that cells are found in animals as well as plants

7. Where does life come from?
Old Theory - Spontaneous Generation
Life spontaneously happens:
Life comes from non-life
Examples:
Mice from cloth sacks and grains.
Maggots from rotting meat.
REALLY?

8. Where does life come from?
Much doubt existed around Spontaneous Generation
Conclusively disproved by Louis Pasteur
Ummm, I don’t think so!!! ? = +

9. Where does life come from?
1858- Rudolf Virchow, German physician, after extensive study of cellular pathology, concluded that cells must arise from preexisting cells.
Biogenesis – Life can only be formed from existing life.

10. The Compound Light Microscope (review)
Lenses
Light
You’ve used it!!
Up to x1500

11. Our Microscope…

12. The Electron Microscope (review)
Biggest magnification
(X 2,000,000)
2 types
(SEM and TEM)

13. The Cell Theory 1. All organisms are composed of one or more cells.
2. The Cell is the smallest working unit of living things.
3. All cells come from pre-existing cells through cell division.

14. Examples of Cells
Amoeba
Plants
Bacteria
Red Blood Cell
Nerve Cell

15. Two Types of Cells
Prokaryotic
Eukeryotic
REMEMBER US

16. Prokaryotic Cells “Old School”
Do not have a membrane-bound nucleus or organelles
Few internal structures (organelles)
Usually one-celled organisms like bacteria
Smaller in size (1-10 um)

17. Eukaryotic Cells “New School”
They do contain a membrane-bound nucleus and organelles and are more complex.
May be unicellular or multicellular
Larger in size (10-100um)
Animal
Plant

18. Cellular Organization Copy
Colonies = group of genetically identical cells living together (bacteria), can live independantly
Multicelluarity = groups of cells with specific roles in an organism
Tissues  Organ  Organ System
Volvox
Pediastrum

19. Why are cells so small?
Surface area-to volume ratio: small cells more efficient
Small size = more surface area
More surface area = easier transport of nutrients, oxygen, waste
Pg. 73, Figure 4-5

20. DIFFUSION
Movement of molecules from an area of higher concentration to an area of lower concentration 1 2 3 4

21. How do things actually get in and out of the cell?
Through diffusion and osmosis
Cell membrane and membrane structures act as the gatekeeper

22. How does diffusion occur?
Passive Transport = doesn’t require energy
Concentration Gradient = difference in concentration across a distance
Equilibrium = concentration of molecules will be the same throughout the space
Even at equilibrium molecules are still moving around
[K] = concentration

23. Simple Diffusion = diffusion across membranes, only certain molecules are allowed across through pores

24. OSMOSIS
Diffusion of water from high concentration to low concentration
Moves mostly through passive transport
Water is always moving in and out of your cells

25. Which direction does the H2O move?
If the solution is…
Hypotonic
Means [K] of solutes outside of cell is lower than [K] of solutes in cytosol) water moves into the cell
Cell will swell (get larger)
Think hypo…o’s are round and chubby, like a plump little cell

26. If the solution is… Hypertonic
[K] of solutes outside of cell is higher than [K] of solutes in cytosol
Water moves out of the cell
Cell shrinks and shrivels up

27. If the solution is… Isotonic
[K] of solutes inside & outside cell are =
Water moves in & out at equal rates

29.  HOW CELLS DEAL W/ OSMOSIS
What happens if you live in a hypotonic environment?
Get rid of extra water entering cells, contractile vacuole
Get rid of extra solutes so less water comes into cell

30. Turgor Pressure = pressure of water against cell wall, occurs in hypotonic environment
Plasmolysis = water leaves cell & cell shrinks away from cell wall, occurs in hypertonic environment

31. Cytolysis = bursting of cells , in a hypotonic environment too much water can move into cell

32. Organelles
-Are (typically) membrane-bound structures with particular functions within eukaryotic cells.
-Are on the surface of cells as well as inside the cell membrane.

33. Surrounding the Cell

34. Cell Membrane (Animal and Plant)
Job:
Boundary between the inside and the outside of a cell
Is selectively permeable: (think Mr. Parker!)
Composed of:
Phospholipid bilayer
Transport proteins
The model of the cell membrane is called the Fluid-Mosaic Model. (fluid – phospholipids move w/in the membrane, mosaic – patters created proteins on membrane surface)

35.  Composition of a phospholipid

36. Cell Wall (Plant) Most commonly found in plant cells & bacteria
Job: Supports & protects cells, almost acts as a shell
Composed of: Cellulose fibrils

37. Cillia and Flagella (Animal and Prokaryotes)
Job: Helps cells move and aids in fluid transport
Cilia = many little hairs on the cell body
Flagella = few/one tail(s)
Location: On the exterior of the cell – in the cell matrix.
Composed of: membrane bound cylinders

38. Inside the Cell

39. Nucleus (Plant and Animal)
Job:
Directs cell activities, storage of genetic info (the brain of the cell)
Location:
Separated from the cytoplasm by the nuclear membrane (envelope)
Composed of:
chromatin (DNA) which is the blueprint for proteins

40. Cytoplasm (Plant and Animal)
Job:
Suspension of eukaryotic organelles
Site of numerous chemical reactions
Location:
Inside the cell membrane, inside individual organelles
Composed of: Cytosol
Water, salts, protein filaments, and organic compounds
~ 70% of a cell’s volume

41. Endoplasmic Reticulum (ER) (Animal and Plant)
Job: site of cellular chemical reactions, assembly of proteins
Rough: protein synthesis
Smooth: numerous biochemical activities, production and storage of lipids
Location: in the cytoplasm
Composed of: A highly folded membrane, Rough ER has ribosomes imbedded in it for protein synthesis

42. Ribosomes (Plant and Animal)
Each cell contains thousands
Job: Make proteins
Location: Found on the ER, on the nuclear envelope & floating throughout the cell
Composed of: simple structure of 2 subunits:
RNA
protein

43. Mitochondria (Plant and Animal)
Job:
Produces energy (ATP) through chemical reactions known as cellular respiration
Breaks down sugar molecules
Location:
in the cytoplasm
Composed of:
membranes (outer, and a highly-folded inner membrane) and specific enzymes
Facts:
Occur in various #s depending on cell function
Has its own DNA

44. Golgi Apparatus (Plant and Animal)
Job: Packaging plant
Sorts proteins into packages and packs them into vesicles to be sent where they are needed
Location: In the cytoplasm
Composed of: System like a flat stack of tubes

45. Lysosomes (Animal) Job: Location: In the cytoplasm
Digestive factory and breaks down waste (proteins, fats, and carbohydrates) with enzymes
Transports undigested material to cell membrane for removal
Location: In the cytoplasm
Composed of: Digestive enzymes enclosed in a protective membrane and a lipid bilayer
Cell breaks down if lysosomes explode - this is how a tadpole looses its tail when it turns into a frog!

46. Vacuoles (Plant and Animal)
Job:
Storage, digestion, and waste removal
Helps plants maintain their shape
Location:
In the cytoplasm
Composed of:
Water & a thin membrane

47. Chloroplast (Plant) Job: Location: Composed of:
Capture light energy (in thylakoid membranes) and convert it into chemical energy through photosynthesis.
Location:
In the cytoplasm
Composed of:
A double membrane
Grana – stacks of membranous sacs

48. Cytoskeleton (Plant and Animal)
Job:
Support and structure (think tent poles!)
Cell division and transport
Anchors organelles
Location:
In the cytoplasm
Composed of:
Microtubules: thin hollow cylinders made of protein
Microfilaments: smaller, solid protein fibers

52. Let’s compare…