The Cell

7.1 Cell discovery and cell theory

How do we study cells?

With

MICROSCOPES!!!!!!

7.1 Objectives Identify the parts of a microscope Match scientists with key discoveries Compare light and electron

microscopes Identify the 3 parts of cell theory Explain the main differences between

eukaryotic and prokaryotic cells

Compound Light

Microscopes (what we will use)

The guys who started it all… Zacharias and Hans Janssen invent

the world's first 2 lens (compound) microscope in 1590.

The guys who started it all… 1665 Robert Hooke

Looking at cork Chambers (named

them cells) Anton van

Leeuwenhoek Single lens

microscope Pond water 1st to discover living

cells“animalcules” (protists)

Why the long gap between inventions?

Few advancement in the mid 19th century Spontaneous Generation (widely accepted,

traditional belief that life arises from nonlife) Examples:

Mice were created from damp hay and corn in a dark corner Maggots/Flies came from

rotting meat Mud could give rise to worms,

insects, and fish

19th Century Advancement Spontaneous Generation = doubters Louis Pasteur

Disproved and replaced theory with… Theory of Biogenesis (states that only living

organisms can produce other living organisms)

Designed an experiment to show this was true even for microorganisms

Development of the Cell Theory

Matthias Schleiden: (1838- German Botanist) plant parts are made of cells

Theodor Schwann: (1839- German physiologist) animal tissues are composed of cells.

Johannes Purkinje (1840) First to observe cell division First to observe the living contents of a cell

Development of the Cell Theory Rudolf Virchow (1858- German

physician) concluded that cells must arise from

preexisting cells

Because of them, today we have…

Advancing technology Light microscopes

Electron microscopes Early 1900’s Higher resolution

Scanning probe microscopy

Fluorescence and light microscopy Uses fluorescence and phosphorescence

in addition to, reflection and absorption

What do you know about cells?

Cell Theory: 3 parts 1. All living things are made of cells

Composed of cells (Matthis Schleiden 1838- plants were made of cells; Theodor Schwann 1839-animals too!)

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

3. New cells are made from existing cells (Rudolf Virchow 1855)

All Cells… Surrounded by a cell barrier (cell

membrane) Carry biological information at some

point (DNA) Vary in size and shape

Two different types Prokaryotic and Eukaryotic

Prokaryotic vs. Eukaryotic Prokaryotes Eukaryotes

• “Pro” = Before• Karyon =

nucleus

• “E = True

• Karyon = nucleus

• True nucleus

• Size: Large/Complex

• Membrane bound organelles

• Membrane bound nucleus with linear DNA

• Some have cell walls

• Multicellular or unicellular

Found in Kingdoms:• Animalia• Plantea• Protista• Fungi

• No true nucleus

• Size: Small/primative

• No membrane bound organelles

• DNA is small and in a ring

• Cell wall

• Unicellular-colonies

• Free Ribosomes (small)

Found in Kingdoms:

• Archaea • Bacteria