Founding Fathers Of Microscopy

UNIT 4: chapter 1

Would you like a slice of cell?

Prokaryotic Cell

Cell membrane

Cell membrane

Cytoplasm

Cytoplasm

Nucleus

Organelles

Eukaryotic Cell

BIOLOGY AND HISTORY

THE HISTORY OF A CELL

So, who discovered a cell anyway?

• The observations and conclusions of many scientists helped to develop the current understanding of a cell.

• What is Cytology? cyto- -ology-

So, who discovered living cells anyway?

1. Anton Leeuwenhoek 2. Theodor Schwann3. Matthais Scheiden 4. Rudolf Virchow 5. Robert Hooke

Anton Leeuwenhoek, 1674• Van Leeuwenhoek was a Dutch

fabric merchant but considered himself an amateur scientist.  He looked at many different things through his microscope (teeth scapings, rainwater, blood) and observed living cells which he called "animalcules".  He wrote many papers that were widely accepted by the scientific community which was unusual for a non-scholar.

• Discovered that living things live in pond water.

Theodor Schwann

German physiologist who founded modern histology by defining the cell as the basic unit of animal structure.

Robert, 1665 • Hooke was an English

scientist who looked at cork through a compound microscope and observed tiny room-like structures that reminded him of the "cells" that monks lived in.  Therefore these structures became known as cells.  The cork cells where not alive so he only saw the cell wall.

Matthais Scheiden

Discovered that all plants are made up of cells.

Rudolf Virchow

• Discovered that new cells are created from old cells.

What is a Theory??

• Theory is a well tested explanation that comes from a broad range of observations.

• (ex. BIG BANG, EVOLUTION, RELATIVITY,ETC.)

Uno, Dos, Tres!!3 CELL THEORIES:

1. All living things are made up of cells.

2. Cells are the basic unit of structure and function of living things.

3. New cells come from pre-existing cells.

2 cell types…

• Prokaryotes-cells that DO NOT have a nucleus.–Bacteria cells

• Eukaryotes-cells that DO have a nucleus.– Animal cells– Plant cells

VS.

ACTIVITY: Venn diagram

Similarity?

1. Definition: Eukaryotes 1. Definition: Prokaryote

DID YOU WASH YOUR HANDS; I THINK I SEE BACTERIA!!! EWW

• CAN WE HONESTLY SEE BACTERIA WITH THE NAKED EYE?

• JUST AN EYE, NO.• WITH A MICROSCOPE, YES!!!!

LEVELS OF ORGANIZATION

ORGANISM (HUMAN,etc.)ORGAN SYSTEM

ORGANTISSUE

CELLMOLECULE

ATOMSIMPLE

COMPLEX

A CELL IS MADE UP OF MANYMOLECULES.

Notes: • Science depends on experimental and

observational confirmation and is subject to change as new evidence becomes available.

• The development and refinement of magnifying lenses and light microscopes made the observation and description of microscopic organisms and living cells possible.

• The development of cell theory was accelerated by the ability to make observations on a microscopic level.

Types of Microscopes:

1. Compound Light Microscope 2. Electron Microscope 3. Transmission Electron Microscope

(TEM)4. Scanning Electron Microscope (SEM)

Compound Microscope

• The light microscope, so called because it employs visible light to detect small objects, is probably the most well-known and well-used research tool in biology.

Electron Microscope • An electron microscope

is a type of microscope that uses electrons as a way to illuminate and create an image of a specimen. It has much higher magnification and resolving power than a light microscope, with magnifications up to about two million times, compared to about two thousand that can be achieved with visible light.

Transmission Electron Microscope (TEM)

• TEM is an imaging technique whereby a beam of electrons is transmitted through a specimen, then an image is formed, magnified and directed to appear either on a fluorescent screen or layer of photographic film.

Scanning Electron Microscope (SEM)

• The scanning electron microscope (SEM) is a type of electron microscope capable of producing high-resolution images of a sample surface.

Magnification Chart

OCULAR LENSES(EYE PIECE)

OBJECTIVE (KNOBS NEAR STAGE)

TOTAL MAGNIFICATION

10 X 40X = 400X

10 X 10 X = 100 X

WHICH MAGNIFICATION ENLARGES A SPECIMEN? ZOOMS OUT?

• “All science begins with astonishment, but the human behind the instrument is much more important than the instrument itself.” --Plato