microscopes instruments used to magnify & view objects

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Microscopes Instruments used to magnify & view objects

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Microscopes

Instruments used to magnify & view objects

In the beginning…

Diseases were thought to be caused by “supernatural spirits” and “curses”

Anton van Leeuwenhoek

●1600’s

●1st view of “animalcules”oAKA cells & bacteria

●Simple Light Microscope, only 1 lens

Robert Hooke

●English scientist●Compound light microscopeo2 or more lenses

●Looked at cork (dead cells on oak bark)oSaw small geometric shapes, named them CELLS

●Cells-> are the basic units of all living things●http://www.wwnorton.com/nael/18century/topic_3/microscope

.htm

What did he see?

http://www.cbs.dtu.dk/staff/dave/roanoke/bio101ch05.htm

Then What?

●1830’s●More scientists used Hooke’s ideas to explore the natural world●Matthias Shleiden, a germanoPlants are composed of cells

●Theodor SchwannoAnimals are composed of cells

●Summarized in the Cell Theory

Cell Theory

The Cell Theory:

3 Main Ideas:

1.All organisms are composed of 1 or more cells.

2.The cell is the basic unit of structure & organization of organisms.

3.All cells come from preexisting cells.

Types of Microscopes

Types of Microscopes

●Light Microscope: what we use in laboUses light to magnifyoUsed to look at living cellsoMagnify: up to 1500x

●Electron Microscope: (1930-1940)oUses beams of electronsoMagnify: up to 500,000xoSee inside of cells, look at structureso2 types

Scanning Electron Microscope: (SEM)

●Scan surfaces of cells, look at 3D shape

http://mse.iastate.edu/microscopy/whatsem.html

http://www.mos.org/sln/sem/diatom.html

Transmission Electron Microscope

(TEM)●Look at structures within the cell

http://en.wikipedia.org/wiki/Transmission_electron_microscope

New Technology

●New models & helpful techniques all the time

●Example: Scanning Tunneling MicroscopeoUses flow of electrons to create computer images of atoms on the surface of a molecule

www.chem.utoronto.ca/staff/DHIRANI/index.htm

The Cell:

●With better microscopes, discovered that cells contain small specialized structures called organelles

●Each organelle has a specific function within a cell

Types of Cells:●2 broad groups:

1.Eukaryotes: contain membrane-bounded organelles (ex. nucleus)

Most multi-cellular organisms & some unicellular ones, like algae

Complex cells

2.Prokaryotes: do not contain membrane-bound organelles (ex. No nucleus, but nucleoid region when chromatin is stored).

Example: bacteria

Less complex

Many functions occur on cell membrane

What do they look like?

http://en.wikipedia.org/wiki/Eukaryotic

http://www.earthlife.net/prokaryotes/images/bacteria.gif