1. Unit 4: Cells

2. The Discovery of the Cell
Cell: the smallest unit that can carry on all the processes of life.
Because the cell is SO small, we need microscopes to see them.

3. The Discovery of the Cell
Robert Hooke : English
Looked at the cork
Named the small components within the cork “cells” because they looked like the cell blocks from prison.
He was looking at the cell walls of dead plants.
***Yes, cork comes from a plant!

4. The Discovery of the Cell
Anton Van Leeuwenhoek (pronounced “Levin-hook”) Dutch
First person to actually observe a living cell!
Improved lenses of the microscopes
Observed pond water and scrapings of teeth!

5. The Discovery of the Cell
Matthias Schleiden and Theodore Schwann (German)
Schleiden- observed plants and said “all plants are made of cells”
Schwann- observed animals and said “all animals are made of cells”
These two side theories led to part of the cell theory

6. The Cell Theory All living things are made of cells.
Cells are the basic structure and function of living things.
All cells come from pre-existing cells.

8. Microscopes Light Microscope
Light passes through the object or lense to eye or computer
Light Microscope
Bacterium or larger (0.2 micrometers in diameter)
Magnifies up to 1000x
Cannot see the internal cell structure
Useful for living specimen

9. Electron Microscope
Uses beams of electrons that bounce of objects to create image
Magnifies up to 1,000,000 x
Reveals details of internal cell structure
Specimen must be dead
SEM: Scanning Electron Microscope
studies the surface structures of objects/cells
TEM: Transmission Electron Microscope
Explores deep internal structures of objects/cells
Micrograph: photograph taken through an electron microscope.

10. Cell Structure Organelles: internal structures of the cell
Each organelle has a specific function.
Plant and animal cells DO NOT have all the same organelles.

13. Cell Shape Most cells have a specific shape
The shape depends on the function

14. Cell Shape
Example:
Cells of the nervous system need to carry information from your brain all the way to your toes.
Therefore, they are long and skinny.

15. Cell Shape
Example:
Blood cells need to travel smoothly through veins and vessels.
Therefore, they are small and round.

16. 2 main classes of Cells Prokaryotic Eukaryotic
Lacks a nucleus, but still has most organelles.
Has a nucleus, and has organelles.
DNA is not separate from the cell.
DNA is protected inside the nucleus.
Size: micrometers
Size: 10 – 100 micrometers
Example: Bacterial Cell
Example: Plant or Animal Cell

19. Cell Organization in Multicellular Organisms
Cells
The smallest unit of life capable of carrying out all functions/characteristic of life.
Tissues
A group of cells working together towards the same function.
Organs
Several types of tissues functioning together for a specific purpose.
Organ System
Several organs working together to perform a function to help the organism carry out all other functions.
Organism
All the organ systems working together to create one being.

20. Tissues of Plants Dermal Tissue Ground Tissue Vascular Tissue
Forms the outer layer of the plant
Ground Tissue
Makes up the bulk of the roots and stems
Vascular Tissue
Transports water and food throughout the plant

21. Organs of Plants
Roots
Stems
Leaves
Flowers