View of the Cell.

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Chapter 7: A View Of The Cell

Ch. 7.1 The Discovery of Cells

The History of the Cell Theory-

Before microscopes disease thought to come from supernatural means

Cells- the basic unit of living organisms

Development of light microscopes-

Simple microscopes vs. compound

Compound light microscopes- a series of lenses to magnify objects in steps, magnify up to 1,500 times

The Cell Theory-

Anton Van Leeuwenhoek- first person to record looking at water under a microscope.

Robert Hooke- viewed cork, gave us the name "cells"

Matthias Schleiden- concluded that all plants are composed of cells

Theodore Schwann- concluded that all animals are composed of cells

1. All organisms are composed of one or more cells

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

3. All cells come from preexisting cells

Development of electron microscopes

Electron microscopes- uses a beam of electrons instead of light to magnify structures up to 500,000times

1. Scanning Electron Microscope (SEM)- scans the surface to show 3D surface images

2. Transmission Electron Microscope (TEM)- allows us to see inside cells

3. Scanning Tunneling Microscope (STM)- investigates atoms on the surface of a molecule

4. Staining, other techniques for contrast

Two Basic Cell Types-

- Prokaryotes- organisms made of cells that lack membrane bound organelles

- Eukaryotes- organisms made of cells with membrane bound organelles, multicellular plants & animals

- Organelles- membrane bound structures with in a eukaryotic cell

* Membrane separates chemical reactions

* Robert Brown- observed nucleus

* Rudolf Virchow- determined nucleus is structure responsible for cell division

* Nucleus- central membrane-bound organelle that manages cellular functions

Ch. 7.2 The Plasma Membrane

Provides a barrier between the internal components of a cell and its external environment.

Maintaining a Balance-

Survival depends on the cell's ability to maintain the proper conditions within itself.