The wacky history of the cell theory

Microscopy • Janssen’s microscope (1590’s)

capable of magnifying images approximately three times when fully closed and up to ten times when extended to the maximum.

Van Leeuwenhoek

• “The Father of Microbiology”

• first person to observe and describe single celled organisms (microorganisms)

• first to record and observe muscle fibers, bacteria, spermatozoa and blood flow in capillaries (small blood vessels).

Robert Hooke (1665)

Coined the term “cell”

Eyes on your notes packet!

• our compound microscopes are called light microscopes

• parts of microscope (diagram sheet) and their functions

• lenses:

• 1. eyepiece lens: 10x

2. objective lenses:

• very low: 5x (total=50X)

• Low: 10x (total= 100X)

• high: 43x (total=430X)

• oil: 97x (total=970X)

• light microscopes limited to 2000x

• why? The wave length of light only allows us to see object at 2000X or less

• resolution drops with increase in magnification

• resolution= the ability to see detail in a in/on an object under the microsope

• unit of measure = μ micron (SI unit of length measurement) = 0.000001m

TEM’s: Transmission Electron Microscopes

• use electrons in place of light

• focus with magnets

• electron beam passes through thin section of object (therefore not alive)

• magnifies 200,000x: photo enlarged 5x: total= 1,000,000X

• (no resolution problems)

Transmission Electron Microscope (TEM)

SEM’s: Scanning Electron

Microscopes

•shows surface of object in 3D

•allows very high magnification

Scanning electron microscopes (SEM)

Match the image with the type of microscope that produces it

Light microscope

Scanning electron microscope

Transmission electron microscope

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