Post on 28-Dec-2015
Life Is Cellular
Section 7.1
Discovery of the Cell• Cells remained “out of
sight” until microscopes were invented.
• In the late 1500’s, eyeglass makers in Europe discovered that using several glass lenses in combination could magnify the smallest objects to make them easier to see.
Early Microscopes
• 1665-Robert Hooke used an early compound microscope to look at a nonliving slice of cork.
• He called the empty chambers “cells”
Early Microscopes (cont.)
• Anton van Leeuwenhoek used a single lens microscope to observe pond water and other things.
• Saw a fantastic tiny world of living things.
Electron Microscopes
• Two major types: Transmission and Scanning.
• Transmission- Form flat and 2-D images.
• Scanning- Produces 3-D images.
Exploring the Cell• Microscopes use lenses
to magnify the image of an object by focusing light or electrons.
Most familiar microscope:
Compound Light Microscope
• Using chemical stains or dyes help see the cell better.
The Cell TheoryCell Theory-1) All living things are made up of cells.
2) Cells are the basic units of structure and function in living things.
3) New cells are produced from existing cells.
Concept #1- A polar bear is made up of many cells.
Concept #3- All polar bears cells came from a single living cell. They divide and they grow to replace old dead cells.
Concept #2- Different cells in a polar bear’s body does different jobs. Example: Fat cells provide insulation and energy, white blood cells carry oxygen.
Prokaryotes and Eukaryotes• All cells are surrounded
by a thin flexible barrier called a Cell Membrane.
• Cells are divided into two categories: Prokaryotes and Eukaryotes
• The nucleus is a large membrane- enclosed structure that contains genetic material in the form of DNA.
Prokaryotes• Cells that do not
enclose DNA in nuclei.
• Mainly smaller and simpler than eukaryotic cells.
• Main examples are bacteria.
Eukaryotes• Cells that enclose their
DNA in nuclei.
• Mainly larger and more complex than prokaryotic cells.
• Most contain dozens of structures and internal membranes.
• Examples: Plant and Animal Cells