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Unit 2: Cells & Microscope. Cell Objectives:. 1. Know the Organization of life. 2. Know who first saw cells. 3. Know The Cell Theory. 4. Know the differences between Prokaryotic and Eukaryotic cells. 5. Know the 12 organelles in Eukaryotic cells. - PowerPoint PPT Presentation
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Unit 2: Cells& Microscope
Cell Objectives: 1. Know the Organization of life.
2. Know who first saw cells.
3. Know The Cell Theory.
4. Know the differences between Prokaryotic and Eukaryotic cells.
5. Know the 12 organelles in Eukaryotic cells.
6. Know the differences between plant and animal cells.
Cells
All living things are composed of cells.
A cell is a membrane-covered structure that contains all of the materials necessary for life.
An organism is anything that can live on its own.
Organisms can be unicellular or multicellular.
Unicellular: Made up of only one cell. They usually need to be seen using a microscope.
Multi-cellular: Made up of more than one cell. They have groups of cells that work together.
Discovery of CellsCells were discovered in 1665 by Robert Hooke.
He was looking at cork from the bark of a tree using a microscope.
Anton van Leeuwenhoek saw the first living cells in 1673.
He observed pond scum, blood and was the first person to see bacteria.
The Cell TheoryScientists later discovered a lot more about cells using
more powerful microscopes.
They developed The Cell Theory.
The Cell Theory States:
o Cells are the smallest living thing
o Every living thing is made of cells
o Cells divide to form new cells
Theodor Schwann developed the theory in 1839.
Organization of LifeFor Multi-cellular organisms:
cells
tissues
organisms
organ systems
organs
Make up
Make up
Make up
Make up
Types of CellsProkaryotic:
Eukaryotic:
Cells that do NOT have a nucleus
Do NOT have membrane bound organelles
Circular DNA
Bacteria
Cells that DO have a nucleus
Do have membrane bound organelles
Linear DNA
All other organisms
Cell Parts (Organelles)
• cytoplasm
• cell membrane
• cell wall
• nucleus
• nucleolus
• ribosomes
• endoplasmic reticulum
• mitochondria
• chloroplast
• Golgi complex
• vacuole
• lysosomes
Eukaryotic Cells:
Types of Eukaryotic Cells
Animal:
Plant:
Types of Eukaryotic Cells
Animal:
Plant:
Function of cell parts
1. Cytoplasm
Jelly-like fluid inside cell
Organelles are found floating here
Function of cell parts
2. Cell Membrane
Protects the cell
Keeps cytoplasm inside
Allows materials in and out of the cell
Function of cell parts
Provides strength and support to cell membrane
Found only in plant cells
Gives plant cells their square shape
3. Cell Wall
Cell wall
Cell membrane
Function of cell parts
Control center of the cell = “brain”
Where DNA is found
4. Nucleus
5. Nucleolus
Stores materials to make ribosomes
Found inside nucleus
Function of cell parts
Site of protein synthesis
Amino acids are joined together to make proteins.
Are found in cytoplasm or attached to endoplasmic reticulum
Smallest but most abundant organelle
6. Ribosomes
Function of cell parts
Internal delivery system
Makes lipids and other materials for inside and outside the cell.
Breaks down drugs and other harmful chemicals.
May be covered with ribosomes (Rough Endoplasmic Reticulum)
Found near nucleus
7. Endoplasmic Reticulum (ER)
Function of cell parts
Powerhouse of the cell
Energy for the cell is made here from nutrients
Surrounded by two membranes
8. Mitochondria
Function of cell parts
Absorbs sunlight to help plants make nutrients for energy
Contains chlorophyll (green pigment)
Found only in plant cells
9. Chloroplast
Function of cell parts
Materials are packaged in vesicles for shipment outside of the cell.
Located near the cell membrane
10. Golgi Complex
Function of cell parts
Stores water and other liquids
Large vacuoles found in plants
11. Vacuole
Contractile Vacuole:
Squeezes excess water out of the cell
Function of cell parts
Digest (breakdown) materials found in vesicles with enzymes (chemicals).
Get rid of wastes
Protect the cell against invaders
Found in Animal cells
12. Lysosomes
Golgi Complex
cell membrane
nucleolus
cell wall
chloroplast
nucleus
lysosome
ribosome
cytoplasm
DNA
ER
mitochondria
vacuole
Animal CellPlant Cell
Comparing Plant & Animal Cells
AnimalPlant
Both
lysosomesCell wall
Chloroplast
vacuole
Cell membrane
nucleus
cytoplasmmitochondria
Golgi complexribosomes
ER
nucleolus
DNA
Microscope Objectives:
1. Know the parts of the microscope.
2. Know the functions of microscope parts.
3. Know how to determine orientation of an object under the microscope.
4. Know how to determine magnification, field of view and size of an object.
5. Know proper technique to use microscope.
Microscope parts
Use this diagram to label your microscope picture
Microscope FunctionsEyepiece:The part you look through. Where you
place your eye.
Arm: Attaches eyepiece to the base.
Body tube: Supports the eyepiece
Coarse adjustment knob:
Fine adjustment knob:
This moves the stage up and down to get object into initial focus.
NEVER use under high power.Used to make small adjustments to the focus.
Microscope FunctionsNosepiece:Rotating piece that changes objectives (low &
high)
Objectives:
Stage:
Stage clips:
Diaphragm:
Light source:
Lens that magnify the object
The place where the specimen is placed.
Holds the specimen slide in place.
Allows different amounts of light through the slide.Reflects light onto the stage to observe specimen
Supports the entire microscopeBase:
Determining total magnification
Multiply the magnification of the eyepiece by the magnification of the objective.
Eyepiece = 10x Objective = 4x
Total magnification = 10 x 4 = 40x
Eyepiece = 10x Objective = 40x
Total magnification = 10 x 40 = 400x
Object Orientation
As you look through the eyepiece the image you see is upside down and backwards from the specimen on the slide.
e slidecover slip
If you move the slide to the left the object moves to the right in the eyepiece.
If you move the slide to the right the object moves to the left in the eyepiece.
Field of ViewEach mark = 1 mm or 1000 μm
Determine the field of view by counting marks under low power.
100x
100x
Field of view = 3mm or 3000 μm
Determining object size
Using the determined field of view:
1. Count the number of cells in a row.
2. Divide the number of cells into the field of view in μm.1. 6 cells
2. 3000 μm / 6 cells = 500 μm (size of one cell)