Life Science Chapter 2 Section 3 pp. 50- 57 Discovering Cells Life Science Chapter 2 Section 3 pp. 50- 57

An Overview of Cells What are Cells? Cells are the basic units of structure and function in living things Structure-what living things are made of Function-the processes that keep an organism alive (what it does (its job) One square cm of skin contains over 100,000 cells Skin Cells

First Observation of Cells a MICROSCOPE is an instrument that makes small things look big The invention of the microscope made it possible for … people to discover and learn about cells

First Observation of Cells A SIMPLE microscope has only one lens A COMPOUND microscope has more than one lens

Robert Hooke In 1633, he was one of the first to observe cells with a microscope he made 1633 Hooke used his microscope to look at the structure of a thin slice of cork (the bark of the cork oak tree) He felt the small empty spaces looked like tiny rectangular rooms, so he called the empty spaces “cells” which is a word meaning “small rooms.”

Cork Cells as Drawn by Hooke

Cork Cells under 100x Magnification

Anton van Leeuwenhoek (pronounced 'vahn Laywenhook') a Dutch tradesman and scientist from the Netherlands. He is commonly known as "the Father of Microbiology". Using his handcrafted microscopes he was the first to observe and describe single celled organisms

Anton van Leeuwenhoek Uses the microscope he built to look at: Drops of lake water Scrapings from teeth and gums Water from rain gutters

Animalcules “Little Animals” Anton van Leeuwenhoek saw moving little animals he called: Animalcules

Microscope Improvements 1590 one of the first compound microscope- uses two lenses

Microscope Improvements 1660 Hooke’s compound microscope uses light to help see

Microscope Improvements 1674 Leeuwenhoek’s simple microscope can magnify 266 times

1886 Microscope Improvements Modern Compound Light Microscope can magnify up to 1,000 times

Microscope Improvements 1933 Transmission Electron Microscope (TEM) using electrons, it can magnify up to 500,000 times

Microscope Improvements 1965 Scanning Electron Microscope can see in 3D and magnify up to 150,000 times

Microscope Improvements 1981 Scanning Tunneling Microscope can magnify up to 1,000,000 times

Schleiden, Schwann, and Virchow 1838 Schleiden concludes: ALL plants are made of cells 1839 Schwann concludes: ALL animals are made of cells Therefore, ALL LIVING THINGS ARE MADE OF CELLS However, no one can explain where cells come from 1855 Virchow writes: New cells are only formed from cells that already exist… or ALL CELLS COME FROM OTHER CELLS .

What the Cell Theory Says Schleiden, Schwann, Virchow and others helped develop the cell theory. Cell Theory is a widely accepted explanation for the relationship between cells and living things. THE CELL THEORY STATES THE FOLLOWING: All living things are composed of cells. Cells are the basic units of structure and function in living things. All cells are produced from other cells.

Light and Electron Microscopes The lenses in light microscopes magnify an object by bending the light that passes through them

Compound Microscope Magnification Total magnification is equal to the two lenses multiplied together 20x 30x So 20 x 30 = 600 times larger

Electron Microscope A microscope that uses a beam of electrons instead of light to produce a magnified image is called an ELECTRON microscope ELECTRON

Hidden Worlds… Fly Foot An image of a streptococcus bacteria taken by a scanning electron microscope. Magnified around 2,000,000x Fly Foot

Electric guitar string Alien Life??? Weevil pyralidae moth Electric guitar string

You Know These!!! Edge of a dime leaf Strand of hair Sponge (only 23x) Snowflake