Differences between bacteria and viruses:
http://www.youtube.com/watch?v=sHThHRV4uo
http://www.youtube.com/watch?v=Rpj0em
EGShQ- how the flu attacks your body
 What is a microbe?
 What is a pathogen?
Measles outbreak interactive map:
http://www.cfr.org/interactives/GH_Vaccine_Map/#map
Bubonic plague is one of the deadliest pandemics in human history. It killed 3060% of Europe’s population between 1348-1350 and took 150 years for Europe's
population to recover.
Since AIDS was first recognized in 1981, it has led to the deaths of more than
25 million people, making it one of the most destructive diseases in recorded
history.
Dairy product produced by fermentation of milk. People have been making
and eating yogurt for atleast 5,500 years!
Global outbreak that began in Mexico, approximately 600,000 people infected
world-wide.
Humulin was the first medication produced using modern genetic engineering
techniques in which actual human DNA is inserted into a host cell. The host
cells are then allowed to grow and reproduce normally, and due to the inserted
human DNA, they produce a synthetic version of human insulin. Humulin can be
used as a treatment for diabetes.
• Unicellular
• Prokaryotic
• Can be autotrophs or heterotrophs
• Can be aerobic (uses oxygen) or
anaerobic
• Can be motile or non-motile
– For motility bacteria have cilia or flagella
Bacteria come in a wide range of
shapes, sizes and colours!
Bacillus
Spirulina
Bordetella
Clostridium
Staphylococcus Streptococcus
Escherichia
Salmonella
• Asexual reproduction is called binary
fission
• Sexual reproduction is called
conjugation
• Some bacteria also form endospores
to survive harsh conditions and then
germinate when conditions become
favorable
Binary
Fission
1 bacterium
can become
1/2 million in
6-7 hours
Based on Harvard Medical
School Family Health Guide
 Conjugation-
Exchanging genetic
information in which a
hollow bridge forms
between two bacteria
cells and genes are
passed. This increases
genetic diversity.
• We depend on Escherichia coli in our
intestines to provide us with Vitamin K and
B Complex vitamins.
• Lactobacillus bulgaricus found in cheese
and yogurt.
– Aids in the digestion of lactose by producing
the enzyme lactase.
– Boosts the immune system
• Staphylococcus aureus-food poisoning
when toxins are ingested
• Streptococcus pyogenes-causes strep
throat—red spots on your throat are red
blood cells the bacteria have destroyed
• Clostridium botulinum-produces toxins that
cause paralysis for 4-6 months (botox
injections are made of these toxins!!!)
• Pasteurization is used to
remove bacteria from food
• Antiseptics can kill bacteria
on tissues
• Antibiotics are used to kill
bacteria that have entered
the body
• Vaccines can prevent
bacterial infections by
stimulating the immune
system
 Some are AUTOTROPHS, meaning they make their own
food from inorganic molecules.


Photoautotrophs which use light energy to convert carbon dioxide
and water to carbon compounds and oxygen in a process similar to
that used by plants.
Chemoautotrophs which uses energy directly from chemical
reactions involving ammonia, hydrogen sulfide, nitrates, sulfur and
iron.
 Bacteria that needs oxygen to live= obligate aerobes.
 Bacteria that can survive without oxygen=facultative
anaerobes.
• A non-living parasite
• Made of nucleic acids, proteins, and
sometimes lipids
• Highly specific to the types of cells they
infect (bacteriophages are viruses that
infect bacteria)
• Do not obtain or use energy; Depends
entirely on a host to survive
• Able to evolve
 Inner core of nucleic acid, either RNA or DNA;
containing information to make copies of the
virus
 Outer protein coat called a capsid
 Large viruses have envelope surrounding capsid
A non-living, disease causing parasite that
invades the cell.
It turns the cell into a virus making factory
until it no longer needs the cell.
It then destroys the cell releasing new viruses
to continue the cycle.
http://www.youtube.com/watch?v=Rpj0emEGShQ
 Once attached to the plasma membrane of
the host cell, the virus enters the cell and
takes over its metabolism. Only then can the
virus replicate.
http://www.tvdsb.on.ca/westmin/science/sbi3a1/Bacvirus/Virusrep.htm
1. The virus may inject its nucleic acid into the
host cell like a syringe injects a vaccine into
your arm
2. An enveloped virus enters a host differently.
After attachment, the plasma membrane of
the host cell surrounds the virus and
produces a virus-filled vacuole inside the
host cell’s cytoplasm. Then, the virus bursts
out of the vacuole and releases its nucleic
acid into the cell.
 A typical lytic cycle takes about 30 minutes and
produces about 200 new viruses.
 The viral genes alter the host cell to make new
viruses. The host cell uses its own enzymes, raw
materials, and energy to make copies of viral genes
that along with viral proteins are assembled into
new viruses, which burst from the host cell, killing
it.
 Does not kill cell like lytic cycle does
 Begins like the lytic cycle. The virus attaches
to the host cell’s plasma membrane and its
nucleic acid enters the cell.
 Instead of immediately taking over the host’s
genetic material, the viral DNA is integrated
into the host cell’s chromosome.
 Viral DNA that is integrated into the host cell’s
chromosome is called a provirus.
 A provirus may not affect the functioning of its
host cell.
 Every time the host cell reproduces, the provirus is
replicated along with the host cell’s chromosome.
Therefore, every cell that originates from an
infected host cell has a copy of the provirus.
 The lysogenic phase can continue for many years.




However, at any time, the provirus can be activated
and enter a lytic cycle. Then the virus replicates and
kills the host cell.
Process explains the reoccurrence of cold sores, which
are caused by the herpes simplex I virus.
Even though a cold sore heals, the herpes simplex I
virus remains in your cells as a provirus. When the
provirus enters a lytic cycle, another cold sore erupts.
Physical and emotional stress play a role in activating a
provirus
Chicken pox and shingles
 Alive
 Capable of reproducing on its own
 Capable of growing and developing during its
‘life’ cycle
 Rhinoviruses cause the common cold
 HPV (Human papillomavirus) can cause cervical
cancer in women
 Herpes simplex viruses cause mouth and/or
genital sores, lesions, and ulcers.
 Influenza viruses cause the flu
 HIV (Human Immunodeficiency Virus) causes
AIDS and weakens the immune system
http://www.youtube.com/watch?v=YSgkoldBNkI
 Antibiotics DO NOT work on viruses.
 Most human viral infections can be fought off
by the immune system—boost the immune
system with lots of water and rest.
 Vaccines are preventative!!!
 Vaccines will NOT cure you if you are already
sick.
 Vaccines stimulate the immune system to
create antibodies that recognize a certain
virus.
 These antibodies patrol your body and if they
recognize that virus…they call in
reinforcements and your immune system
goes to battle!
 A virus recognizes and attaches to a host cell
when one of its proteins interlocks with a
molecular shape that is the receptor site on the
host cell’s plasma membrane.
 The recognition and attachment process is like
two pieces of a jigsaw puzzle fitting together.
DNA viruses: herpes simplex virus (HSV)
Varicella zoster virus (VZV)
VZV: Chickenpox
VZV: Shingles
Re-activation of latent
infection
 Ebola hemorrhagic fever
(Ebola HF) is a severe,
often-fatal disease in
humans and nonhuman
primates
 Appeared sporadically
since its initial
recognition in 1976.
 Transmission arthropod
bites.
 No known treatment.
 A retrovirus is an RNA virus that is replicated
in a host cell via the enzyme reverse
transcriptase to produce DNA from its RNA
genome.
 The DNA is then incorporated into the host's
genome. The virus thereafter replicates as
part of the host cell's DNA.
 HIV is a retrovirus
 The first virus to be identified was a plant
virus, called tobacco mosaic virus
 400 identified viruses that infect plants with
1000 different diseases
 Cause stunted growth and crop losses
NOT classified because THEY
ARE NOT ALIVE
Classified into the Kingdom
Eubacteria or Archeabacteria
Non-living parasite
Living
Cannot reproduce on their
own (uses a host cell)
Can reproduce sexually or
asexually
Contain DNA or RNA inside Contain circular DNA inside
a protective coating (capsid) a cell membrane and cell
wall
Always pathogenic
Can be helpful or
pathogenic