1. Life is Cellular
Section 7.1

2. Objectives Understand Cell theory
Distinguish between prokaryotes and eukaryotes
Understand different types of microscopy, and how they work in more detail

3. What is a Cell
The smallest part of a living organism that can be considered alive
Pre 1500s nobody cared about cells – if you couldn’t see it it didn’t matter!
In 1665, in Britain cork was analyzed under a microscope, first cells discovered
Bacteria first identified in Holland around the same time
Anton Van Leeuwenhoek

4. 1838, decided that all plants are made of cells
After Van Leeuwenhoek’s discovery, it became clear that cells are the basic units of life
1838, decided that all plants are made of cells
Mattias Schleiden
1839 – all animals made of cells as well
Theodor Schwann
1855 – Shown that cells can reproduce
Rudolf Virchow

5. Cell Theory All living things are made of cells
Cells are the basic units of structure and function in living things
New cells are produced from existing cells

6. Staining microscope slide
Many living cells are transparent
Stains allow us to see a number of features
Can use stains that only pick out specific structures

7. Electron microscopes
Two types – scanning and transmission

8. Prokaryotes vs Eukaryotes
No Nucleus
Nucleus – separates genetic material from the rest of the cell
Small and simple
Often contain dozens of structures and internal membranes
Although simple, fulfil al criteria to be alive
Large amount of variety
Example - Bacteria
Protists live as unicellular organisms
Can form multicellular organisms – plants, animals and fungi
Both come in a range of shapes and sizes
Eurkaryotes tend to be more complex