Transcript Slide 1
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Microbes like bacteria
and viruses are part of
our daily lives! On the
following slides, the red
sections identify the
main points; Underlined
words = vocabulary!
Hyperlinks are in blue.
1.
2.
3.
4.
5.
Knows the meaning
of “microbe”.
Knows the
difference between
a virus and a cell?
Knows an example
of a common virus.
Knows an example
of a common
bacterium.
Knows the meaning
of “pathogen”.
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In 2009 the world was introduced
to swine flu (H1N1) which is caused
by new strain of virus similar to the
common cold; it quickly spread
around the globe.
Tuberculosis, TB (shown here) hit
Houston in 2013!
Microscopic life is everywhere, but
MOST microbes are not deadly!
http://www.bcm.edu/molvir/eidbt/images/TB%20bacteria.jpg
A nefarious baculovirus, that only targets the gypsy moth
caterpillar, infects it's host and forces it to climb to the very top of
a tree, before liquefying it and showering deadly, disease-ridden
goo down onto the other caterpillars below. Horror horror horror.
From Sinister Virus Image
Zombie Caterpillars Video
http://www.intechopen.com/source/html/45362/media/image4.png
Use the colored paper to
create your T-chart on
viruses and bacteria.
There will be the
following bullets to
compare:
Definition
Shapes
▪ Cut out the example
image.
Reproduction
A virus is an infectious agent with
a core of genetic material (DNA
or RNA) and surrounded by a
protein coat [aka capsid] and lipid
envelope.
They are NOT cells
(no membranes or organelles)
Reproduce only within a host
http://visual.ly/node/25794
cell
Considered parasites
Animation
Viruses come in many
shapes.
Viral shapes include:
Helical a twisted coil
Polyhedral a sphere
surrounded by
polygons; EX Herpes
Spherical EX Influenza
+ others
http://2012books.lardbucket.org/books/introduction-to-chemistry-general-organic-andbiological/section_22/c3b305d2e544f371a8602555a5e7fab3.jpg
http://news.bbcimg.co.uk/media/images/65456000/jpg/_65456950_structure_2_small.jpg
Viruses are very host
specific; the protein
arrangement [aka
coding spikes] on the
exterior recognize only
specific cells [like the
lock and key model in
enzymes].
Animation
http://legacy.uspharmacist.com/ce/105382/figure1.jpg
http://whyfiles.org/132aids2/images/virus_movie.gif
A virus needs a host to
reproduce; they have to
use a cell!
A host is an organism
that shelters and
nourishes something
else (think “hostess”).
Viruses reproduce in
three ways:
1. Lytic
2. Lysogenic
3. Retrovirus
Animation
The following information will not fit on your T chart – add
this information to your notebook.
http://www2.bc.cc.ca.us/bio16/images/lyticcycle.jpg
Lytic Cycle – viral replication
that rapidly kills a host cells
1. Virus attaches to cell and
injects its DNA
2. Tricks the host cell, makes
viral mRNA for viral
proteins
3. Enzymes cut up the cell’s
DNA; build viral DNA
4. The cell now builds viruses
5. Cell lyses, or bursts
6. Minion viruses infect other
cells
• EX Flu
Lysogenic Cycle – the virus does
not immediately kill the host cell
[remains dormant] EX Herpes
1. Viral genome inserts itself into
the hosts DNA [provirus]
2. Every time the cell divides, the
“invading” virus’ DNA is copied
3. Eventually, the virus is
eventually activated and enters
the lytic cycle
• EX Herpes
http://upload.wikimedia.org/wikipedia/en/thumb/0/0e/V
iral_Reproduction_Chart.png/300pxViral_Reproduction_Chart.png
Retrovirus - the most complicated form of viral
replication is the retrovirus; prefix retro means
backwards, in this case, from RNA to DNA
1. They produce a copy of DNA using reverse
transcriptase, an enzyme
2. Then follows the steps of lysogenic replication
• EX HIV
http://aws.labome.com/figure/te-174-1.png
http://www.thelibertybeacon.com/wp-content/uploads/2013/01/child_vaccine_blue.jpg
Vaccines - stimulate
the body’s immune
system with a
harmless (weakened)
form of a virus to
create antibodies to
prevent disease
EX Flu shot,
chicken pox
vaccine
Animation
http://floydmiddle.typepad.com/.a/6a00d83452932669e2017c32859dd2970b-pi
Prokaryotes (lack a nucleus
and membrane-bound
organelles)
Unicellular (one cell)
Circular DNA plasmids
Some w/ pili [attachment]
Some w/ flagella
[movement]
"Typical blue-green alga and bacterial cells." The Gale
Encyclopedia of Science. Ed. K. Lee Lerner and Brenda
Wilmoth Lerner. 4th ed. Detroit: Gale, 2008. Science in
Context. Web. 14 Mar. 2014.
Electron micrograph of
Martian meteorite
ALH84001 showing
structures that some
scientists think could be
fossilized bacteria like
life forms. Image
Bacteria comes in many shapes [the colors match the
images]:
Spheres (or cocci)
Rods (or bacilli)
Spirals (or spirilla)
Chains (or strepto)
Clusters/Groups (or staphlyo)
http://biology.clc.uc.edu/graphics/bio106/bacteria.jpg
Colored scanning, electron micrograph (SEM) of anthrax
bacteria (Bacillus anthracis), the cause of the disease
anthrax in humans and livestock. Anthrax is used as in
bioterrorism.
http://srs.dl.ac.uk/Annual_Reports/AnRep01_02/anthrax-bacteria.jpg
Bacteria reproduce
in three ways:
1. Binary fission asexual
reproduction, cell
divides producing
2 identical
daughter cells
Video
http://media.web.britannica.com/eb-media/12/104312-004-2E12350D.jpg
2. Conjugation - sexual
reproduction that
exchanges genetic
material between 2 cells
▪ Moves DNA between
cells, allows for
genetic diversity
▪ Bacterial cells can
mutate to create new
strains
▪ Animation
http://www.wiley.com/college/pratt/0471393878/student/activities/bacterial_drug_resista
nce/conjugation_web.jpg
An endospore. Bacillus anthracis, the
bacterium that causes anthrax, produces
persistent endospores. The thick,
protective coat helps it survive in the soil
for years. Image
3. Spores – some bacteria
delayed reproduction,
thick walls around their
DNA called an
endospore during
unfavorable conditions;
they can resist drought,
heat, even radiation.
When conditions
improve, the
germinates
endospore and the
bacteria grows again.
Foods! EX cheese, yogurt ,
soy sauce, etc.
Some bacteria can remove
waste products from water
and sewage; bacteria has
been modified to consume oil
in oil spills.
Bioremediation – process
of using microorganisms to
help restore natural
environmental conditions.
http://www.capetownskies.com/1058/25_oilspill_workers_closee.jpg
http://weedeco.msu.montana.edu/class/LRES443/Lectures/Lecture20/FoodWeb.JPG
Some bacteria are producers and create oxygen and/or
nitrogen used by some plants and animals.
As decomposers, they recycle nutrients into raw elements.
http://www.biotechnologyonline.gov.au/images/contentpages/antibiotics.jpg
Vaccines - stimulate the
body’s immune system
with antigens to prevent
disease
EX Tuberculosis vaccine
Antibiotics - block the
growth of bacteria
They can be used to
cure and treat many
diseases caused by
bacteria that, in the
past, have been deadly.
Modern bacteria are evolving!
Modern disinfectants,
antiseptics, hand sanitizers, etc.
and anti-bacterial soaps are
designed to kill microbes.
Remember, however, the overuse
of these products and antibiotics
can cause the bacteria to mutate
and become resistant and more
dangerous and difficult to kill.
Super Germs Video
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Some bacteria and viruses [and other types of life] can be
pathogens; some pathogens are deadly, some are not.
Epidemiologists are scientists who study the cause and
spread of diseases [aka pathogens] through populations.
Video