Transcript Cell - fieldbio

10/30
No ATB
 Today:

– Quarter final make ups
– Watch “Life”

Tomorrow:
– Go over quarter finals
– Then go to activities fair

Next week – Start Cells
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BIO-PRINTING
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https://www.youtube.com/watch?v=9D74
9wZSlb0
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Solar-powered sea slug harnesses
stolen plant genes
– http://www.newscientist.com/article/dn16124
-solarpowered-sea-slug-harnesses-stolenplant-genes.html
Green Sea Slug Is Part Animal, Part
Plant
 http://www.wired.com/wiredscience/2010
/01/green-sea-slug/
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Amazing Cells – Univ of Utah
– http://learn.genetics.utah.edu/content/begin/
cells/
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Cell Structures and Functions
– http://library.thinkquest.org/12413/structures.
html
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Cells Alive – Eucaryotic Cell Interactive
Animation
– http://www.cellsalive.com/cells/cell_model.ht
m
Organelle Interactive

Amazing Cells – Univ of Utah
– http://learn.genetics.utah.edu/content/begin/
cells/
– Click “Inside a cell” and explore some of the
organelles.

Cells Alive – Eukaryotic Cell Interactive
Animation
– http://www.cellsalive.com/cells/cell_model.ht
m
– Choose “Plant Cell”
– Scroll over the diagram and click to learn
more about each organelle
11/3 ATB
What structure in the cell holds the DNA?
 Today:
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– Begin discussing cells
– All grades are on MP II
Chapter 7 – Cell
Structure and Function
What are cells?
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Cell – Basic unit of
structure and
function of life
Review: Organization of Living Things
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Organism
Organ system
– A group of organs that accomplish a task
– Examples:
 Digestive system
 Respiratory System
 Nervous System
 Endocrine System
Organ
– A groups of tissues with a particular job
 Cardiovascular System
Tissue
– Group of similar cells with a specific function
Cells
– Basic unit of structure / function of life
Organelle
– Intracellular structures with specific functions
The study of cells…
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What hindered the study of cells for
previous scientists?
– They are very small
– We didn‘t have the technology (microscopes
to see them)

Your body is a habitat for a variety of cells
(vid)
– You have life form living on your body
– http://www.youtube.com/watch?v=Rz4CddJD
U30
Robert Hooke (1665)
Used light microscope to view dead cork
cells (first to see cells)
 Named tiny boxes he saw “cells”
 Under the microscope, cork seemed to
be made of thousands of tiny, empty
chambers that Hooke called “cells”. The
term cell is used in biology to this day.
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Anton van Leeuwenhoek (1673)
First person to observe living cells
 Used simple microscope
(only one lens)
 In Holland, Anton van Leeuwenhoek
examined pond water and and other
things, including a sample taken from a
human mouth. He drew the organisms he
saw in the mouth—which today we call
bacteria.
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Matthias Schleiden
Concluded that all plants are made of cells
(1838)
 German botanist
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Theodor Schwann
Concluded that all animals were made of
cells (1839)
 German zoologist
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Rudolf Virchow
Concluded that new cells could be
produced only from the division of existing
cells
 German physician (1821 – 1902)
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The cell theory states:
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What is the cell theory?
– All living things are made up of cells.
– Cells are the basic units of structure and
function in living things.
– New cells are produced from existing cells.
11/4 ATB
How many lenses does a light microscope
use to magnify the object?
 Today:
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– Discuss cell size
– Describe how cell structure relates to
function.
– Old coats = extra credit
Light Microscopes
and Stains
Uses two lenses to magnify the
object / organism
 Stain allow us to see cell
structures that may otherwise not be visible
 PRO
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– Can be used to study living specimens
– Inexpensive (we can use them)
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CON
– Only able to magnify an object 1000 times
Light Microscopes and Cell Stains
– A typical light microscope allows light to pass through a
specimen and uses two lenses to form an image.
– The first set of lenses, located just above the specimen,
produces an enlarged image of the specimen.
– The second set of lenses magnifies this image still
further.
– Because light waves are diffracted, or scattered, as they
pass through matter, light microscopes can produce
clear images of objects only to a magnification of about
1000 times.
– Another problem with light microscopy is that most
living cells are nearly transparent, making it difficult to
see the structures within them.
– Using chemical stains or dyes can usually solve this
problem. Some of these stains are so specific that they
reveal only compounds or structures within the cell.
Light Microscopes and Cell Stains
– Some dyes give off light of a particular color when
viewed under specific wavelengths of light, a property
called fluorescence.
– Fluorescent dyes can be attached to specific molecules
and can then be made visible using a special
fluorescence microscope.
– Fluorescence microscopy makes it possible to see and
identify the locations of these molecules, and even to
watch them move about in a living cell.
Electron Microscopes – TEM and
SEM
Use beam of electrons that are focused by
a magnetic field.
 Two types: Scanning (SEM) and
Transmission (TEM) electron microscope
 PRO’s
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– Can see very small objects
– (Magnify up to 10,000,000x)
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CON’s
– Specimen must be dead
– Expensive
Yeast Cells
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Light Microscope
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TEM (2D slice)
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SEM (3D)
Light vs. Electron Microscope
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SEM? TEM? LM?
Review
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If you took a quiz right now…how many would
you get correct?
1. How many lenses does a light microscope use to
magnify an object?
2. How do you calculate the magnification of a
microscope?
3. What is one con of a light microscope?
4. What is a pro of electron microscopes?
5. What is a con of electron microscope?
6. Why do we use stains in microscopy?
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“Gentle” Microscope Reveals 3D
Action Shots Of Living Organisms
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http://www.iflscience.com/technology/gen
tle-microscope-reveals-3d-action-shotsliving-organisms
Electron Microscopes
– Light microscopes can be used to see cells and cell
structures as small as 1 millionth of a meter. To study
something smaller than that, scientists need to use
electron microscopes.
– Electron microscopes use beams of electrons, not light,
that are focused by magnetic fields.
– Electron microscopes offer much higher resolution than
light microscopes.
– Because electrons are easily scattered by molecules in
the air, samples examined in both types of electron
microscopes must be placed in a vacuum in order to be
studied.
– Researchers chemically preserve their samples first and
then carefully remove all of the water before placing
them in the microscope.
– This means that electron microscopy can be used to
examine only nonliving cells and tissues.
TEM and SEM
– There are two major types of electron microscopes: transmission
and scanning.
– Transmission electron microscopes make it possible to explore
cell structures and large protein molecules.
– Because beams of electrons can only pass through thin
samples, cells and tissues must be cut first into ultra thin slices
before they can be examined under a transmission electron
microscope.
– Transmission electron microscopes produce flat, twodimensional images.
– In scanning electron microscopes, a pencil-like beam of
electrons is scanned over the surface of a specimen.
– Because the image is of the surface, specimens viewed under a
scanning electron microscope do not have to be cut into thin
slices to be seen.
– Scanning electron microscopes produce three-dimensional
images of the specimen’s surface.
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Cell Shape and Function
Cell shape usually tells us about the cell
function
Function of
Nerve cell?
Shape?
Function of
Skin Cells?
Shape?
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Cell Size
Cell Size
– Cells vary greatly in size
 Nerve cells in giraffe neck vs. Human egg cell - size of a .
 Wide range of sizes: 0.2 – 1000 micrometers
 Average is from 5-50 micrometers
Eukaryotic Cell  10-100 micrometers
Prokaryotic Cell  1-5 micrometers
Cell Size:
http://learn.genetics.utah.edu/content/begin/cells/scale/
11/5 ATB
Why do some cells look differently than
others?
 Today:

– Discuss the differences between prokaryotic
and eukaryotic cells
What limits cell size?
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Cell size is limited by its surface area to
volume ratio
What is the problem with increasing cell
size?
 Volume increases faster than surface area
as a cell grows
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– PROBLEM:
 needed materials can’t
get in fast enough
(O2, glucose) and
wastes out fast
enough (CO2)
 Notice SA increased
only 25 times and the
volume increase
125 times
Prokaryotic vs. Eukaryotic Cells
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Very important that you know the
similarities / differences
Prokaryotic vs. Eukaryotic Cells
– Eukaryotes are cells that enclose their DNA
in nuclei.
– Prokaryotes are cells that do not enclose
DNA in nuclei.
Prokaryotes and Eukaryotes
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Although typical cells range from 5 to 50
micrometers in diameter, the smallest
Mycoplasma bacteria are only 0.2 micrometers
across, so small that they are difficult to see
under even the best light microscopes.
 In contrast, the giant amoeba Chaos chaos may
be 1000 micrometers in diameter, large enough
to be seen with the unaided eye as a tiny speck
in pond water.
 Despite their differences, all cells contain the
molecule that carries biological information—
DNA.
 In addition, all cells are surrounded by a thin,
flexible barrier called a cell membrane.
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Prokaryote
– Do not enclose DNA
in a nucleus
– DNA is found in a
mass in center of cell
– No membrane bound
organelles
– Small / more simple
than eukaryotic cells
– Example:
 Bacteria
Cell Types
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Eukaryote
– DNA found in nucleus
– Made up of 1 or more
cells
– Have membrane
bound organelles
– Larger / more complex
than prokaryotes
– Examples:
 plants, animals,
fungi,“protists”(para
mecium, amoeba)
Cell Types
Eukaryotic cell, prokaryotic cell and
a virus
Venn Diagram
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Similarities / differences between
prokaryotic and eukaryotic cells
Eukaryotic vs. Prokaryotic Cells
Assignment
Book page 194
 #1-4
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Due at end of period.
Which do you think is older?
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Which type of cells are older? Prokaryotic
or Eukaryotic? Why?
– Scientists think prokaryotic cells evolved first,
since they are less complex
Endosymbiosis:
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Endo means: “inside / within”
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Symbiosis means: “living together”
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Endosymbiosis:
As prokaryotic cells evolved they engulfed
other prokaryotic cells, which eventually
became eukaryotic cells
Scientists think that this is how
mitochondria and plastids became
incorporated into plant and animal cells
Evidence?
Mitochondria and plastids have DNA that
varies from the rest of the cell
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Mitochondria have their own DNA and only
reproduce from division of preexisting
mitochondria
Plastid DNA is very similar to DNA of some
photosynthetic bacteria
11/6 ATB
Describe one similarity and one difference
between prokaryotic / eukaryotic cells.
 Today:

– Review the theory of endosymbiosis
– Review the notes so far
– Start filling out note outline using the book on
the cell structures
Endosymbiosis
Endosymbiosis
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THE EVOLUTION OF THE CELL
(endosymbiosis)

http://learn.genetics.utah.edu/content/be
gin/cells/organelles/
Review of the chapter so far
1.
2.
What is the basic unit of life? ____________
Who was the first to see LIVING cells?
1.
3.
Who was the person to see dead cork cell?
1.
4.
5.
6.
7.
9.
10.
11.
12.
Hooke
What are the three parts of the cell theory?
Which microscope can see smaller objects, light or electron microscopes?
Cell structure often relates to cell __________.
What controls cell size?
1.
8.
Leeuwenhoek
Surface area to volume ratio
What is the difference between prokaryotic and eukaryotic cells?
What are some similarities between prokaryotic and eukaryotic cell?
Giver an example of a prokaryotic organism.
Give an example of a eukaryotic organism.
What does the theory of endosymbiosis state?
1.
Prokaryotic cells engulfed other prokaryotic cells to make eukaryotic cells
Books!
Cell Organelles Info – Read!
Page 10 of the notes
 Get your book
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– Starting on page 196 thru 205
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Read about the organelles / structures and answer the
questions
You must get pages 10-11 done today (10 points!)
It would be best to use pencil so you can make
changes --- we will go over these
You will be assigned two or three at a time and then
we will go over them.
You need to complete #1-3 to start.
Book Assign
Page 163
 #1-7
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