1. Cell Theory

2. Microscopes and Cells: History
Don’t copy down this slide – just listen
Microscopes and Cells: History
In 1663, __________ coined the term “cells”
10 years later, _________________ observed bacteria and protozoa
In 1833, __________ observed and coined the term “nucleus”
Robert Hooke
Anton van Leeuwenhoek
Robert Browne
No nucleus
DNA in nucleoid region

3. Guten Tag, Dr. Shwann
Cell Theory: History
Guten Tag, Dr. Schleiden
It appears we have come up with a very similar theory…
In 1838 (and 1839) German scientists, ________________ & ________________ independently came up with the “Cell Theory”
Matthias Schleiden
What shall we call this theory?
Theodore Schwann

4. Cell Theory All living things are made up of one or more cells.
Cells are the smallest basic unit of life, with structure, function, and organization.

5. all cells must come from pre-existing cells.
In 1855, German physician Rudolph Virchow discovered that…
all cells must come from pre-existing cells.
Please add the above as point #3 to the cell theory

6. How big are cells? Eukaryotic cells include _______ & _______ cells.
Most eukaryotic cells are between __ and ___ m.
What is the limit of the light microscope?
Why?
What is used to see smaller objects? __________________
plant
animal 10
100
0.2 m
It is limited to the
visible light spectrum
Electron Microscopes

7. Electron Microscopy
___________ Electron Microscopes (TEM) emit light through a thin piece of heavy metal ion stained tissue
________ Electron Microscopes (SEM) reflect light off of a piece of heavy metal ion stained tissue
Transmission
Scanning

8. Prokaryotic Cells (cells without a nucleus) for ex. bacteria
Label this diagram in your handout
Cell Wall
Circular DNA
Ribosomes
Plasma Membrane
Cytoplasm
Cilium
Cilia
Flagella
Flagellum
TEM of a bacterium

9. Eukaryotic Cells: cells with a nucleus (include plant and animal cells)
Nucleus w/DNA wound in strands
Plant cell
Ribosome
(dots) for making proteins
Membrane organelles
(more membranes within the cell
Animal cell
All organelles are suspended in the cytoplasm of both cells
Plasma Membrane
Cell Wall (not in animals cells)

10. Differences and similarities between Prokaryotes and Eukaryotes
Prokaryotes Eukaryotes
Has a nucleus
Has “membrane” organelles or structures inside the cell
Larger than prokaryotes m (micrometers) in size
Several DNA packaged into strands called chromatin
No nucleus
No “membrane” structures inside the cell
Small 1-10 m (micrometers) in size
One circular piece of DNA
Plasma Membrane
Cytoplasm
DNA or genetic material
Ribosomes that make protein