Download Cells and Cellular Organization

Chapter 3.1 – Looking at Cells
Magnification – making an image appear larger than its
actual size
Resolution – measure of the clarity of an image
Microscopes
Compound light microscope –
Light passes through more than one lens
to produce an enlarged image of a specimen
Both lenses magnify – so if you have a
microscope with a 40X objective lens and a
10X ocular lens your total magnification is
400X
Electron microscopes
Forms an image of a specimen using a
beam of electrons rather than light
Can magnify up to 200,000X
Cannot magnify cells because both the
electron beam & specimen must be placed in
a vacuum chamber so the electrons in the
beam will not bounce off gas molecules in
the air
TEM (Transmission electron microscope):
shows thin slices of a specimen – always in
black & white – if in color it has been added by
a computer
SEM (Scanning electron microscope):
shows the outer, 3D image – again in black &
white – if in color it has been added by a
computer
Scanning probe: detailed surface images
(specimens don’t have to placed in a vacuum)
http://remf.dartmouth.edu/imagesindex.html variety of SEM and TEM images
http://www.nanowerk.com/news/newsid=4546.php rbc/e.coli SPM images
Chapter 3.2 – Cell features
Cells and Cellular Organization
I. Organization of Organisms
Atoms (protons, neutrons, electrons)
smallest
Molecules (H20, etc.)
Macromolecules (Lipids, Carbohydrates, etc.)
Cells (neurons, muscle cell, bone cell, etc.)
Tissue (blood, tendon, cartilage, etc.)
Organ (a single muscle/bone, heart, eyeball, etc.)
Organ System (nervous, circulatory, etc.)
Organism
largest
II. Cell Theory
Robert Hooke: described the units that make up
plants as “cells” (cork cells)
Mattias Schleiden: cells make up every part of
plants
Theordar Schwann: animal tissues were also made
of cells
Robert Brown: discovers the nucleus
Schleiden: nucleus plays a role in cell division
A. All living things are made of a single cell
(bacteria) or many cells (most other
organisms).
1.A single - celled organism is unicellular
2.A many – celled organism is multicellular
B. A cell is the smallest unit of life, nothing
smaller than a cell is considered living – it is the
basic unit of structure & function in organisms
C. All cells come from pre – existing cells through
cell division
III. Cell Structure
A. Surface Area: Volume Ratio
1.Cells obtain substances (such as oxygen and
glucose) by absorption.
2.Cells get rid of substances (carbon dioxide and
wastes) by secretion.
3.Since cells have no complex method of
transport, the cell must be small enough for
the surface area of the cell to service the
contents of the cell.
4.Cell size is limited. Cells must remain small.
5.Cells need large surface area: volume ratios
B. Cell Shape
1.Cells keep shape with a skeleton just like
yours (cytoskeleton)
2.All cells have cell membranes that surround
the cell to regulate contents going in and
coming out. The membrane allows absorption
of glucose and oxygen and allows excretion of
carbon dioxide and wastes. The cell
membrane is made of phospholipids, which
makes sense because the membrane must be
resistant to breakdown by water, which
surrounds the cell. Selectively permeable.
3.Some cells (plant, bacteria) also have cell
walls for support
4.Cytoplasm in the cell is a fluid that allows
absorption and diffusion
C. Cell Size
1.Cell size varies depending on the organism
and function of the cell.
2.Most are microscopic, but some can be 1.0
meter in length.
IV. Cell Types
Prokaryotic
Eukaryotic
Single celled
Multi & Unicellelar
No Nucleus
Nucleus present
Ribosomes,
Many organelles
mitochondria
present
Bacteria Animal, Plant,
Fungus
Protist
A. Prokaryotic
1.Lack organization, no nucleus, one single
strand of DNA
2.Bacteria are examples
B. Eukaryotic
1.Highly organized, many organelles, nucleus
present
2.All multicellular organisms are made of
eukaryotic cells, as well as some unicellular
organisms
C. Comparison of Prokaryotic and Eukaryotic Cells
Comparison of Prokaryote, Animal and Plant Cells by Rodney F. Boyer
Cell Variation
Color images of histological sections home page:
http://www.udel.edu/Biology/Wags/histopage/colorpage/colorpage.htm
Adipose http://www.udel.edu/Biology/Wags/histopage/colorpage/ca/wav.GIF
Neuron http://www.udel.edu/Biology/Wags/histopage/colorpage/cne/cnemnvhl.GIF
Sperm http://www.udel.edu/Biology/Wags/histopage/colorpage/cmr/cmrst6.GIF
Stratified Squamous Epithelium - Skin
http://www.udel.edu/Biology/Wags/histopage/colorpage/cep/cepssq.GIF
Ciliated epithelium http://www.udel.edu/Biology/Wags/histopage/colorpage/cep/cepcpe.GIF
Skeletal muscle http://www.udel.edu/Biology/Wags/histopage/colorpage/cmu/cmustmlt1.GIF
Cardiac muscle http://www.udel.edu/Biology/Wags/histopage/colorpage/cmu/cmucmid.GIF
Cartilage http://www.udel.edu/Biology/Wags/histopage/colorpage/cc/ccfls.GIF
Bone http://www.udel.edu/Biology/Wags/histopage/colorpage/cb/cblc.GIF
Blood cells http://www.udel.edu/Biology/Wags/histopage/colorpage/ch/chbpe.GIF
Elodea http://iws.ccccd.edu/biopage/BioLab/Unit%207/Elodea%20cells%2010x.jpg