The History Behind Cells Where does life come from Spontaneous Generation Spontaneous Generation The idea that life can appear from the nonliving environment Francesco Redi disproved this idea through his meat experiments ID: 489481
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Slide1
Cell Theory
The History Behind CellsSlide2
Where does life come from?Slide3
Spontaneous Generation
Spontaneous Generation: The idea that life can appear from the non-living
environment
Francesco
Redi
disproved this idea through his meat experimentsSlide4
Spontaneous Generation
Louis Pasteur’s ExperimentSlide5
Microscope Invented
Hans & Zacharias Janssen Made 1st
compound microscope (2 lenses)
Allowed people to see things never before seen!Slide6
Robert Hooke 1655
Used microscope to look at oak corkHe observed “tiny little boxes”
Called structures
“cells
” Slide7
Review
Who named cells because they looked like “tiny boxes”?Francesco Redi
Louis Pasteur
Robert Hooke
Albert Einstein Slide8
Anton Van Leeuwenhoek 1675
Used a simple microscope (1 lens):
Observed blood,
rainwater, sperm
etc.
Called them “
animalcules” because they looked like little animalsSlide9
Matthias Schleiden 1838
German botanistDiscovered that
plants
are also made of cells!Slide10
Theodor Schwann 1850
German zoologistViewed animal
parts under microscope
Discovered animals were made of cellsSlide11
Rudolph Virchow 1858
German DoctorConcluded that all living cells come only
from other living cellsSlide12
Review
Who was the first person to observe living cells? (He called them animalcules)Robert Hooke
Francesco
Redi
Anton van Leeuwenhoek
Rudolph VirchowSlide13
Cell Theory
The work of many scientists led to the development of the Cell Theory!The Cell Theory
:
1)
All living things are made from one or more cells
2)
Cells are the basic unit of structure and function in living things3)
All cells come only from other living cellsSlide14
Review
Which is NOT part of the cell theory?All living things are made of 1 or more cells
Cells come from non-living things
Cells come only from other living cells
Cells are the basic unit of structure and functionSlide15
Cool Jobs In Science
Molecular BiologySlide16
The MicroscopeSlide17
Why is it Important?
The microscope allowed scientist to observe things that could not be seen with the naked eyeCells for example!
Makes things appear larger than they really are!Slide18
How does it Work?
Microscopes use glass lenses to bend light
This makes things appear larger or smaller depending on the shape of the lens
Compound microscopes
: have more than one lens!
This means they can magnify things even more!Slide19
Using Scale
If 1hm = 10,000 cmHow many centimeters
is the organism in this
p
icture? Slide20Slide21
Comparing Powers of Magnification
We can see better details with higher the powers of magnification, but we cannot see as much of the image.
Which of these images would be viewed at a higher power of magnification?Slide22
What’s my power?
To calculate the power of magnification,
multipl
y
the
power
of the
ocular lens
by the
power
of the
objective
.
What are the powers of magnification for each of
the objectives we have on our microscopes
?Slide23
Calculating Magnification
To find the total magnification of a compound microscope you must multiply
the magnifying power of
both
lenses!
Example:
Lens 1 = 10X magnificationLens 2 = 50X magnification
Total magnification = 10 X 50 = 500XSlide24
Practice
Ocular Lens is 10x & Objective lens is 7x Total Magnification? 10 X 7 = 70x
Ocular Lens is 4x & Objective lens is 10x Total Magnification?
4 X 10 = 40xSlide25
Electron Microscopes
Today scientists can use electron microscopes to look inside cells! These microscopes use
electrons
instead of light to magnify object even more!
Same particles that light up your television!Slide26
Parts of a MicroscopeSlide27
Function of Parts
Body Tube: separates eyepiece from objective lens
Eyepiece:
contains lens that magnifies 10X
Nosepiece:
holds objectives lenses and allows rotationSlide28
Function of Parts
Objective lens (High Power): Magnifies 40X
Objective lens (Low Power):
Magnifies
10X
Coarse Adjustment Knob:
moves body tube to focus with low-power objective lensFine Adjustment Knob:
moves body tube to focus with high-power objective lensSlide29
Function of Parts
Arm:
supports the body
tube
Base:
supports the
microscopeStage: supports the slide being
used
Stage clip:
holds the slide in placeSlide30
Function of Parts
Diaphragm: controls the amount of light that comes through the stage
Mirror/Light Source:
reflects light upward through diaphragm