Download Bacteria - Mr.Hill`s Biology

BACTERIA:
CLASSIFICATION
STAINING
NUTRITION
RECOMBINATION
Last Day
• We looked at how to describe bacterial
colonies and make purity plates for our
specimens
• Looked at the different structures of
bacteria, and briefly at classification
– What is the difference between Gram
Positive and Gram Negative?
– The amount of peptidoglycan in the…
– Cell wall
• Reminder, all retests must be done by
Wednesday, April 22!!
Outlook for
Today
• Further look at bacterial
classification
• Gram staining procedure
• Gram staining our organisms!
• Bacterial Nutrition
• Recombination and Replication
Time permitting: observing our
Gram stains!
Outlook for
Future
• Antibiotic resistance talk – April 23rd
• Bacteria Unit Test – Tentatively May 1
• Term Reports Due Friday – Please have
all assignments you want updated for
this term done by THURSDAY
• Evol/DNA retests – Today or tomorrow!
• Virus Retest – Wednesday or Thurs!
• Bacteria Quiz – structure, media,
nutrition, classification, recombination
MONDAY, APRIL 27. (FOR MARKS)
Bacterial
classification
• Last Day – We learned about the difference between
Gram positive and Gram negative organisms
• But we can classify bacteria even further
Kingdom
Eubacteria
• There are 12 different phyla of bacteria
according to evolutionary relationships
• There are only 4 we will be focusing on
in this unit
– Table 24-1 in your textbook
– Cyanobacteria
– Spirochetes
– Gram-positive bacteria
– Proteobacteria
Phylum • Once known as Blue-green algae
– Now classified as Eubacteria, as they do not
Cyanobacteria contain any membrane bound organelles
• Photosynthetic (Use sunlight to produce
energy, give off oxygen as a waste product)
prokaryotes
– Responsible for the oxygen in Earth’s
atmosphere today!
• Can grow in chains and form heterocysts
– Used to fix Nitrogen (converting atmospheric
Nitrogen into ammonia for use by plants)
Phylum
Cyanobacteria
• An accumulation of nutrients (nitrates
and phosphates) can lead to an
overgrowth of cyanobacteria known as
eutrophication or population/algal
bloom
– Following eutrophication, many
cyanobacteria die off and are decomposed
by heterotrophic bacteria
– Heterotrophic bacteria consume available
oxygen in water, causing other marine life
to die.
Phylum
Spirochetes
• Gram positive
• Spiral shaped
• Heterotrophic
– Cannot fix carbon, must use
organic carbon for growth
• Aerobic or Anaerobic
– Grow in presence of oxygen or in
absence of oxygen
• Move in cork-screw like rotation
Phylum
Spirochetes
• Can live:
• Freely
– No need for host organism
• Symbiotically
Treponema pallidum
– Lives on/in host organism, both organisms
benefit from relationship
• Parasitic
– Live on/in host organism, only bacterium
(parasite) benefits, while causing harm to
host
• Syphyllis
Phylum
Gram
Positive
Bacteria
Streptococcus sp.
• Despite it’s name… not all members in
this phylum are Gram positive
– Some GN organisms in this phyla
because of their molecular similarities
• Actinomycetes
– GP bacteria that produce many of the
antibiotics we know today
• Many human infections
– Staphylococcus
–  Streptococcus
Phylum
Gram
Positive
Bacteria
Lactobacillus sp.
• Lactobacillus sp.
– Grows in all of us!
– Makes milk turn into yoghurt
– Found in our oral cavity and
intestinal tract
– Help with oral health… but can
also be associated with tooth
decay
Phylum
Proteobacteria
• Gram Negative bacteria
• Can be
–Enteric
–Chemoautotrophs
–Nitrogen Fixing bacteria
Enteric
Bacteria
• Inhabit animal intestinal tracts
• Escherichia coli
– Produces Vitamin K, and
assists with breakdown of
food
• Salmonella spp.
– Responsible for many cases of
food poisoning
Chemoautotrophs
• Extract energy from minerals, by
oxidizing them.
• Iron-oxidizing bacteria
– Grown in high iron concentration lakes
– Can be used in bio-mining
– More on that later!
Nitrogen
fixing
bacteria
• Produce Nitrogen (N2) – the primary
gas in our atmosphere!
• Live on many types of plants – plants
provide them with nutrients, bacteria
provide plants with forms of nitrogen
they can use
– What kind of relationship do we call
this?
– Symbiotic
To do now:
• Gram stain instruction lecture
• ½ of class – Work on
24.1/24.2/finish off notes Review
Silently, so classmates can focus
on gram strain procedure
• Switch after first group is done.
To do now:
• With your partner
• CAREFULLY follow the Gram
stain procedure provided for
you.
• When done, you can read
ahead in 24.2
NUTRITION
+ GROWTH
Heterotrophs • Heterotrophs
– Use organic matter as a source of
and autotrophs nutrition
– Saprophytes
– Feed on dead and decaying material
• Autotrophs
– Obtain their energy from sunlight or
minerals.
Photoautotrophs • Use the sunlight as an energy
source .
– cyanobacteria
Chermoautotrophs
• As we have just learned,
oxidize inorganic minerals to
obtain energy
Living
Environments
• Obligate anaerobe
– CANNOT live in the presence of oxygen
– Clostridium tetani (causes tetanus)
• Facultative anaerobes
– Can live with or without oxygen
– E.coli
• Obligate aerobes
– Cannot survive WITHOUT Oxygen
– Mycobacterium tuberculosis (causes
tuberculosis [TB])
Temperature
Requirements
• Different species of bacteria grow best
at all different temperatures
– Most grow best in 30-35oC range
– Thermophillic bacteria grow best in
high temperatures (40-110oC)
• Most bacteria grow best at pH 6.57[Neutral]
– Lactobacilli (yoghurt, Sour cream)
prefer acidic environments (ph6 or
lower)
GENETIC
RECOMBINATION
Table 24-3
in text
• Ways bacteria can
acquire and express
new genetic
information
Transformation
• When a bacterial cell takes in
DNA from the external
environment.
• New material substitutes out
existing, similar material and
becomes part of the bacterial
chromosome
Conjugation
• Bind together, one bacteria can
exchange genetic information with
another
• Genetic Donor must contain special
plasmid and pillus
• Binds to recipient bacterium, forms a
conjugation bridge
• Plasmid replicates in donor cell, then
replicated plasmid transfers over
conjugation bridge into recipient cell
• After DNA transfer, cells detach
Transduction • Bacteria and viruses working
together!
• Virus takes up fragments of
bacterial DNA.
• After Virus replicates, and is
released, it will find new
bacteria to transfer DNA into.
• Old bacterium's genes can be
expressed in new bacteria