Transcript Bacteria - nowyoudothemath

Bacteria
Kingdom Archaea
• Previously, we learned about the need for the taxa
domain to help distinguish between the different types
of bacteria.
• The domain Archaea was created to group organisms
that did not quite fit into the kingdom bacteria due to
their gene sequence, metabolism, and physical
structure.
• It is believed that archaea are the oldest group of
organisms on Earth.
• When evolutionists examine the genetic composition
of archaea, they determined these prokaryotes
resemble eukaryotic organisms more than bacteria.
• The phylogenetic tree would show that eukaryotes, like
humans, and archaea have a common ancestor.
• Archaea are prokaryotic
unicellular organisms. They
do not have a nucleus nor
do they have membrane
bound organelles.
• However, they do have a
cell wall and a cell
membrane that is
structurally different from
bacteria.
• In addition, archaea live in
extreme environmental
conditions.
• The structure of their cell
membrane allows for their
survival in extremely acidic
conditions, saline
environments and also in
oxygen-free areas.
The halobacteria shown here
lives in an extremely salty
environment.
Kingdom Eubacteria
• Bacteria are the most abundant and most
diverse organisms on Earth.
• All bacteria are single-celled and prokaryotic
(they do not have a nucleus).
• Their DNA consists of a single chromosome.
• Bacteria do not have any membrane bound
organelles and they reproduce asexually by
binary fission.
• Bacteria are only 1-10 µm and therefore can only be
seen with the help of a microscope.
• The bacteria Salmonella, which causes diarrhea,
fever and abdominal cramps in humans, is shown.
• The image has been magnified 20863x using a
colourized scanning electron micrograph (SEM).
Structure of Bacteria
• All bacteria
have the same
basic structure.
• The diagram
below shows
the crosssection of the
bacterial cell.
• You will notice
that some
structures,
cytoplasm,
ribosomes are
common to
eukaryotic cells
as well.
Virtual Microscope
• http://www.udel.edu/biology/ketcham/micro
scope/
• Watch the instructional video to refresh how
to use a microscope
• Then click on the virtual microscope link and
examine a slide of a bacterial capsule
• While the structure of bacterial cells is very similar,
their shape is not.
• Bacterial cells are classified based upon their
shape.
• There are three basic shapes:
Rod-shaped
Spiral-shaped
Spherical-shaped
Rod-shaped
Bacilli(pl.) Bacillus(sing.)
Spiral-shaped
Spirilla (pl.) Spirillum(sing.)
Spherical-shaped
Cocci (pl) Coccus(sing.)
• Bacteria cells also have different types of
arrangements.
• If they are clustered, like a bunch of grapes
they are referred to as staphylo.
• If they are arranged in pairs they are
called diplo and if they exist in long chains
they are called strepto.
This image has been
magnified 900x.
• In the image on the left,
you will notice fine
dotted red lines.
• This is the
bacteria streptococcus
pyrogenes.
• It is arranged in long
chains (strepto) and has
a spherical shape
(coccus).
• Streptococcus
pyrogenes is
responsible for strep
throat and scarlet fever.
Practice – Match the following
Staplococcus
Spirillum
Diplococci
Diplobacillus
Streptococcus
Streptobacillus
Homework
• Name the type of Archaea that would survive in
the following environmental conditions:
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Sewage sludge
Dead Sea
Hot sulphur springs
Antarctic
Human Intestines
• Archaea play an important role in biotechnology.
What qualities make these organisms so useful?
• Describe the function of each component of the
bacterial cell shown on slide six.