http://img.dailymail.co.uk/i/pix/2007/09_04/salmonella2409_468x398.jpg
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.
Engage Clip
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”.
http://p4.storage.canalblog.com/46/00/400229/49620127.jpg
 Zika is the current virus spreading
in the Western hemisphere.
 Last year, it was Ebola which
caused 28,637 cases and 11,315
deaths worldwide
 Tuberculosis, TB (shown here) hit
Houston in 2013 and closed schools!
 Microbes are everywhere, but
MOST microbes are not deadly!
http://www.bcm.edu/molvir/eidbt/images/TB%20bacteria.jpg
http://insanemedicine.com/wp-content/uploads/2015/12/zika-microcephaly.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
 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
http://news.bbcimg.co.uk/media/images/65456000/jpg/_65456950_structure_2_small.jpg
http://www.ppdictionary.com/viruses/virus_sizes.jpg
 This diagram compares a human liver cell, a single
ribosome, and a bacterium, to some common viruses.
 Viruses are very very small (b/w .003 ~ .05 microns)!
 Viruses come in many
shapes.
 Viral shapes can 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://learnsomescience.com/wp-content/uploads/2010/02/Various-Viral-Shapes.jpg
 Viruses are very host
specific; the protein
arrangement [aka coding
spikes] on the exterior
recognize specific cells [like
the lock and key model in
enzymes].
 A host is an organism that
shelters and nourishes
something else (think
“hostess”).
http://legacy.uspharmacist.com/ce/105382/figure1.jpg
 A virus needs a host to
reproduce; they have to
use a cell!
 Viruses reproduce 3
ways:
1. Lytic
2. Lysogenic
3. Retrovirus
http://whyfiles.org/132aids2/images/virus_movie.gif
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
causes symptoms.
• 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
weakened form of a
virus to stimulate the
immune system.
 Meant to prevent
disease
 EX Flu shot,
chicken pox
vaccine
 Animation
 Prokaryotes (lack a nucleus
and membrane-bound
organelles)
 Unicellular (one cell)
 Circular DNA plasmids
 Some w/ pili [attachment]
 Some w/ cilia or 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.
http://floydmiddle.typepad.com/.a/6a00d83452932669e2017c32859dd2970b-pi
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.
Potato spindle tuber viroid
(PSTVd) in tomatoe plants. Image
 Viroids cause disease in plants
 Just a single strand of RNA molecule w/ no capsid
 Prions cause disease in animals
 Just particles of protein
 EX Mad cow disease and Creutzfeldt-Jakob disease may
be caused by prions.
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.
 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
 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
http://www.chiropracticresearch.org/washhands.jpg