discovering cells life science chapter 2 section 3 pp. 50- 57
TRANSCRIPT
Discovering Discovering CellsCells
Life ScienceLife Science
Chapter 2 Section 3Chapter 2 Section 3
pp. 50- 57pp. 50- 57
What are Cells?What are Cells?
Cells are the basic units of Cells are the basic units of structure and function in living structure and function in living thingsthings Structure: what living things are Structure: what living things are
made ofmade of Function: the processes that Function: the processes that
keep an organism alive keep an organism alive
One square cm of skin One square cm of skin contains over contains over
100,000 cells100,000 cellsSkin CellsSkin Cells
First Observation of CellsFirst Observation of Cells
MICROSCOPE MICROSCOPE
is an instrument that makes is an instrument that makes smallsmall things look things look bigbigThe invention of the microscope made it The invention of the microscope made it
possible for …possible for …people to discover people to discover
and learn about cellsand learn about cells
First Observation of CellsFirst Observation of Cells
A A SIMPLESIMPLE microscope has only one lens microscope has only one lens
A A COMPOUNDCOMPOUND microscopemicroscope
has more than one lenshas more than one lens
Robert HookeRobert Hooke In 1633, one of the first to observe cells In 1633, one of the first to observe cells
with a microscope that he madewith a microscope that he made 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 HookeCork Cells as Drawn by Hooke
Cork Cells under 100x Cork Cells under 100x MagnificationMagnification
Anton van LeeuwenhoekAnton van Leeuwenhoek(pronounced 'vahn Laywenhook')(pronounced 'vahn Laywenhook') Dutch tradesman and scientist Dutch tradesman and scientist
from the Netherlands. from the Netherlands. He is commonly known as "the He is commonly known as "the
Father of Microbiology". Father of Microbiology". Using his handmade Using his handmade
microscopes, he was the first microscopes, he was the first to observe and describe single to observe and describe single celled organismscelled organisms
Anton van LeeuwenhoekAnton van Leeuwenhoek
Uses the microscope Uses the microscope he built to look at:he built to look at:
Drops of lake waterDrops of lake waterScrapings from teeth Scrapings from teeth
and gumsand gumsWater from rain Water from rain
guttersgutters
““Little Animals”Little Animals”
• Anton van Anton van Leeuwenhoek Leeuwenhoek saw moving saw moving little animals little animals he called:he called:
AnimalculesAnimalcules
Schleiden, Schwann, and VirchowSchleiden, Schwann, and Virchow
1838 1838 SchleidenSchleiden concludes: ALL plants are made of cells concludes: ALL plants are made of cells 1839 1839 SchwannSchwann concludes: ALL animals are made of concludes: ALL animals are made of
cellscells Therefore, Therefore, ALL LIVING THINGS ARE MADE OF CELLSALL LIVING THINGS ARE MADE OF CELLS However, no one could explain where cells come fromHowever, no one could explain where cells come from 1855 1855 VirchowVirchow writes: New cells are only formed from writes: New cells are only formed from
cells that already exist…cells that already exist… or or ALL CELLS COME FROM CELLSALL CELLS COME FROM CELLS
The Cell TheoryThe Cell Theory Schleiden, Schwann, Virchow and others helped develop Schleiden, Schwann, Virchow and others helped develop
the the cell theory.cell theory. Cell Theory Cell Theory is a widely accepted explanation for the
relationship between cells and living things.
THE CELL THEORY STATES THE FOLLOWING:THE CELL THEORY STATES THE FOLLOWING: All living things are composed of cellsAll living things are composed of cells Cells are the basic units of structure and Cells are the basic units of structure and
function in living things.function in living things. All cells are produced from other cellsAll cells are produced from other cells..
Microscope TimelineMicroscope Timeline
1590 one of the first compound microscope- uses two lenses
Microscope TimelineMicroscope Timeline
1660Hooke’s compound microscope uses light to help see
Microscope TimelineMicroscope Timeline
1674Leeuwenhoek’s simple microscope can magnify 266 times
Microscope Microscope Timeline
1886Modern Compound Light Microscope can magnify up to 1,000 times
Microscope TimelineMicroscope Timeline
1933Transmission Electron Microscope (TEM)
using electrons, it can magnify up to 500,000 times
Microscope TimelineMicroscope Timeline
1965 SEM -Scanning Electron Microscope can see in 3D and magnify up to 150,000
times
Microscope TimelineMicroscope Timeline
1981 STM Scanning Tunneling Microscope can magnify up to 1,000,000
times
Light and Electron MicroscopesLight and Electron Microscopes
The lenses in light microscopes magnify The lenses in light microscopes magnify an object byan object bybending the light bending the light
that passes through that passes through
themthem
Compound Microscope Compound Microscope MagnificationMagnification
20x
30x
Total magnification is equal to the two lenses multiplied together
So 20 x 30 =So 20 x 30 =600 times larger600 times larger
Electron MicroscopeElectron Microscope
A microscope that uses a beam of electrons instead of light to produce a magnified image is called an
ELECTRON microscopeELECTRON
Hidden Worlds…Hidden Worlds…
An image of a streptococcus bacteria taken by a scanning
electron microscope. Magnified around 2,000,000x
Fly Foot
Alien Life???Alien Life???
Weevil pyralidae moth
Electric guitar string
You Know These!!!You Know These!!!Edge of a dime
Sponge (only 23x)
leaf
Snowflake
Strand of hair