Download Bacteria powerpoint

What are Bacteria?
• Bacteria are PROKARYOTES
– The smallest known living cells
Bacteria on
head of a pin
They are found
everywhere!!
Starr, 317
Did you know? There are over 80
species of bacteria in your mouth!
Bacteria in dental plaque
microbeworld.org
Some cause disease
We call these “pathogens”
Anthrax, as seen by Koch
microbeworld.org
But most are
beneficial
Bacteria ferment cheese
Schraer, 641
Characteristics of Bacteria
Most have a cell wall
Many have a capsule (jelly or
slimy coating outside the cell
wall, for protection)
Schraer, 632
They have a single, circular
chromosome.
Some have plasmids (tiny
rings of DNA separate
from the chromosome.)
Cytoplasmic Pili help them
talk to other cells.
Many can MOVE
Some have flagella - made of
rope-like proteins, not
microtubules.
Some slide on a slimy secretion.
Salmonella
www.iwate.jp
Many can form dormant
cells called endospores
to survive harsh conditions.
Streptomyces spores
Three basic
shapes
• Spherical – coccus
• Rod – bacillus
• Coiled - spirillum
Schraer, 633
Simple Colonies
Staphylo = clusters
Strepto = chains
Staphylococcus
wisc.edu
Streptobacillus
Diplo = double
Diplococcus
cat.cc.md.us
Reproduction in bacteria
• Purpose is to make
more bacteria. It is
considered
ASEXUAL
REPRODUCTION
because only one cell
is needed.
• In this process the
bacteria splits into two
to create more cells.
• It is known as binary
fission.
Binary fission
(for a quick clone)
Normal bacterial reproduction
1) chromosome replicates
2) copies separate as cell
wall lengthens
3) cell membrane pinches in
4) septum/new wall grows
5) cells divide
Steps in binary fission
Bacillus dividing by fission
SixKingdoms.html
maricopa.edu
How Bacteria Populations Grow!!
Growth Curve (in Culture)
Schraer, 634
See Fission in Action
•
In ideal conditions, some
species can divide every 10 MINUTES.
• Did you know?
What stops them?
They run out of food or space,
or wastes build up and poison them.
Nutrition
Most are heterotrophs
- saprobes or parasites
Autotrophs
-photosynthetic or chemosynthetic
Did you know? Chemosynthetic bacteria are
the base of the food chain at ocean floor vents.
Little is Better!!
Metabolism is FAST
Bacteria can absorb nutrients and
secrete wastes rapidly because of high
surface-to-volume ratio
Did you know? Lactose fermenters break
down 10,000 times their weight in lactose in
an HOUR!
Two Kingdoms of Bacteria
• Kingdom Archaebacteria
- “Ancient”, most primitive
earliest known form of life
-
•Kingdom Eubacteria
- includes bacteria and
Fluorescent micrograph
of an archaeon
cyanobacteria (blue-green)
microbeworld.org
Kingdom Eubacteria
Photosynthetic – 2 groups
1) cyanobacteria (aerobes)
– Have chlorophyll a
and phycocyanin (blue)
– Other colors, too
– Most live in fresh water
– Others live in salt water,
soil and lichens
Nostoc
Schraer, 637
Starr, 315
More photosynthetics
2) green-sulfur and purple bacteria
- anaerobic
- colors range from pink to black
- photosynthesize without water
- make no oxygen
- live in pond and sea mud
Biologic Importance of
Bacteria
1) Essential to nutrient cycling
2) Decomposers – in soil, inside animals
Enterobacteria – live inside us,
break down waste, make vitamins
3) Process foods – cheese, yogurt, pickles
4) Some MAKE antibiotics (streptomyacin)
5) Used in cell and molecular research,
genetic engineering, medical research..
Sources
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Schraer and Stoltz, Biology, the Study of Life, 7th ed. Prentice-Hall, 1999
Starr, Cecie, Biology, Concepts and Application, Wadsworth Group, 2003
Fission www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookmito.html
www.biology.hawaii.edu/bio171/Notes/Bacteria/page6.htm
Archaebacteria http://biology.com/learning/archaea/introduction.html
Staphylococcus http://www.bact.wisc.edu/Bact330/lecturestaph
Conjugation http://tidepool.st.usm.edu/crswr/bactconjug.html
Legume nodules http://www.danieldeepak.com/bacteria.htm
Salmonella http://www.office.pref.iwate.jp/~hp1002/eiseika/salmonella.jpg
Bacteria reproducing
http://marshallteachers.sandi.net/teacher_sites/mcquillan/04.Classificatio
n/Readings/SixKingdoms.html
Dental plaque
http://www.microbeworld.org/htm/aboutmicro/microbes/types/.htm
Fission time-lapse http://www.cellsalive.com/ecoli.htm
Diplococcus
http://www.cat.cc.md.us/courses/bio141/labmanua/lab16/diplo.html