Transcript Ch. 2-Cells Lecture #2

Viewing Cells
2.2
I. Microscopes
Put magnification to work…
1) Go out side and grab a
leaf or blade of grass.
2) Make a wet-mount slide
3)Observe and draw a
picture (label the cell wall,
chloroplasts, vacoule and
nucleus)
I. Microscopes
A. 1st Microscope
1. Antonie van Leeuwenhoek
2. Late 1500’s
3. Noticed that 2 lenses
from reading glasses made
an image bigger.
4. Magnified image 270X
I. Microscopes
B. Compound Microscope
1. Uses 2 lenses (simple only
uses 1)
1 lens in the eyepiece
X
1 objective lens
---------------------------Total Magnification
I. Microscopes
2. Eyepiece = 10
X
Objective Lens = 40
-----------------------Magnification = 400X
3. Compound microscopes
can magnify up to 2000X
I. Microscopes
C. Electron Microscopes
1. Uses a beam of electrons
instead of a light beam
a. Images are viewed in a
vacuum so they cannot be
alive.
2. Can magnify up to
1,000,000X
I. Microscopes
3. Types of Electron
Microscopes
a. Scanning Electron
Microscope (SEM)
1)Makes a 3-D image of
the cell’s surface.
I. Microscopes
b. Transmission Electron
Microscope (TEM)
1)Makes a 2-D image of
the structures inside the
cell
I. Microscopes
c. Scanning Tunneling
Microscope (STM)
1) Shows the atoms on
the surface of a cell
2) VERY POWERFULL!
3) Uses computer
generated graphics
II. Cell Theory
A. All organisms are made up of 1
or more cells
1. Hooke first noticed cells
1. Schleiden noticed this in
plants
2. Schwann noticed this in
animal cells
B. The cell is the basic unit of
organization in organisms
II. Cell Theory
C. All Cells come from preexisting cells
1. Virchow noticed that cells
divide from other cells to
reproduce
III. Prokaryote vs. Eukaryote
A. Prokaryote (“Pro” means NO)
1. No nucleus
2. No nucleus
3. No membrane-bound
organelles (Not very organized)
4. No more than 1 cell (Singlecelled organisms)
III. Prokaryote vs. Eukaryote
B. Eukaryote
1. Has a nucleus
2. Has membrane bound
organelles
3. More organized
4. Single or multi-celled
organisms
RECAP
-Who is the inventor of the
microscope
-What kind of microscope uses
2 lenses to magnify
-How is an electron microscope
different from a compound
microscope
RECAP
-What are the 3 parts of the
cell theory?
-Who named cells? Why did he
name them cells?
-What is the difference
between a prokaryote and a
eukaryote?