Transcript Cells and microscopes

Do Now
• What are cells?
• Why do we need them?
• List different types of cells that you know
of…
Objective
• Describe how cells were discovered and
named.
• Identify the scientists that discovered and
observed cells.
• List the 3 parts of the cell theory.
LETS CELLEBRATE!
Chapter 1
What are Cells?
a) Basic structural
and functional unit
of all living
organisms!
b) They come in all
shapes and sizes
Lets take a look…
How were they discovered?
a) The light microscope led to the discovery of cells.
Who discovered cells?
i. Observed dead cork
cells.
ii. Said boxes looked like
tiny rooms or cells,
that is where they get
their name.
iii. Used a microscope at
30x magnification
Who discovered cells?
i. Observed pond
water.
ii. 1st to observe living
cells.
iii. Used a
microscope at 300x
magnification
But WHERE do they
come from????
Hmmmm…
What happens when you leave
meat out?
Fransisco Redi Experiment
He placed meat in both an open
container, and a closed container to
see what happened…
Redi’s Conclusion…
-Maggots come from
FLIES, not meat.
-Life must come from
life, not spontaneous
generation right?
-Nobody believed him!
Where do cells come from?
i. Discovered that cells
must come from other
cells.
ii. He disproved the theory
of “spontaneous
generation”- theory
that life can just
appear out of
nowhere.
Pasteur’s Experiment
Pasteur’s Experiment
• Control group• Experimental group-
Pasteur’s Results
• flask that was exposed to the air contained
bacteria in it from the air. Flask that wasn’t
exposed did not contain anything. The
cells must come from living things in the
air!!
Pasteurization
*Pasteur came up with the idea of
Pasteurization after discovering bacteria
could contaminate milk from the air. This
process kills the bacteria so that it does
not harm us!
Cell Theory!
Cells come
only from
other living
cells.
Every living
thing is
made of 1 or
more cells.
Cells carry
out the
functions
needed to
support life.
Do Now
• When you drew your slides in lab, were
they in 3D?
• What would be the benefit of seeing
something in 3D?
• Could you see through the specimens that
you were looking at?
• Why might this be beneficial?
Objective
• Compare and contrast a scanning electron
microscope vs. a transmission electron
microscope.
• Describe prokaryotic and eukaryotic cells.
Section 1.2 - MICROSCOPES
• How small are cells?
– We use micrometers
(μm )= 1 millionth of a
meter!
– Range from 1 μm to
1000 μm
Types of Microscopes
A) Compound Light
Microscrope (LM)
B) Scanning electron
microscope
(SEM)
C) Transmission
electron
microscope (TEM)
Compound Light Microscope
i. Uses light
ii. Thin specimen
iii. Total
magnification =
40x-100x
iv. Used to see
cells, but not
organelles
inside
Scanning Electron Microscope
(SEM)
i. Uses
electrons
that bounce
off the
specimen
ii. 3-D image,
must be
dead 
iii. Specimen
is coated in
metal
iv. Total
Transmission Electron
Microscope (TEM)
i. Uses
electrons
to deflect
through
specimen
ii. Thin
specimen
iii. Total
magnificat
ion=
300,000x
Prokaryotes vs. Eukaryotes
What do you notice that is different between these 2 cells?
Prokaryotic Cells
i. Have
circular
DNA
ii. NO
nucleus
iii. Doesn’t
have
membran
e-bound
organelles
iv. Most
Example: Bacteria
Eukaryotic Cells
Multicellular
Eukaryote
i. Have linear
DNA that is
in a double
helix shape.
ii. Has a
nucleus.
Unicellular Eukaryote
iii. Have
membranebound
organelles.
iv. Mostly
Where did these cells come
from?
Scientist: Lynn Margulis
Theory: organelles in
eukaryotic cells were once
prokaryotes that were
engulfed!
Theory= EVIDENCE!!
i. Mitochondria have circular DNA like
bacteria
ii. Replicates (reproduces) like bacteria
separate from the host cell
iii. Mitochondria make their own proteins
iv. Mitochondria have two membranes
(one from the host cell and one from
their own cell membrane)