What are the characteristics of viruses Bacteria What kingdom do each of these belong Are they living Why or why not Kingdoms Eukar What do you already know What are the differences between viruses and bacteria ID: 917950
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Slide1
Bacteria & Viruses
Slide2What are the characteristics of viruses? Bacteria? What kingdom do each of these belong? Are they living? Why or why not
?
Slide3KingdomsEukar
Slide4What do you already know?
What are the differences between viruses and bacteria?
Are all bacteria harmful?
When you get a cold, should you take an antibiotic to help you get better?
What’s the best and easiest thing to do to avoid getting sick?
Slide5Bacteria Video
Slide6Bacteria
Bacteriology
is the study of bacteria
Bacteria are
prokaryotic, unicellular
organisms containing
DNA
and
riboso
mes
.
Bacteria have
ALL
the characteristics of living things.
Bacteria have the
greatest percentage
of the
biomass
on Earth!
Slide7Bacterial Structure
Basic structure of bacteria
:
Ribosome
Pili
DNA
Flagellum
Peptidoglycan*
Cell
wall
Cell
membrane
Slide8Bacterial Structure
Bacteria have
three distinct shapes
:
spherical
(cocci)
rod-shaped
(bacilli)
spiral
(spirilla
)
Slide9Are bacteria harmful or useful?
Slide10Bacteria
Bacteria have a variety of important uses:
Help make interesting food
(buttermilk, yogurt, cheese, sauerkraut, pickles, and olives, etc…)
Decompose organic matter
(recycle nutrients from dead organisms; break down sewage into simpler compounds)
Nitrogen fixation
(chemically changes nitrogen gas, N
2
, into ammonia, NH
3
, so plants can make amino acids)
Human health
(bacteria on skin help prevent infection & bacteria in gut helps digest food & make vitamins)
Biotechnology
(used to make antibiotics, insulin, human growth hormone, vitamins, and other drugs)
Slide11How Do Pathogenic Bacteria Work?
Bacteria produce disease in one of two ways:
Using cells for food
: The bacteria break down healthy cells for food, destroying tissues
Releasing toxins
: The bacteria produce a toxin (poisonous protein) that is released into the bloodstream where it can travel throughout the body, disrupting normal activity and damaging tissues
Slide12Bacteria
A rather vocal
minority
(
less
than
1%
) of bacteria cause disease in humans, animals, and plants.
Bacteria can cause a variety of diseases:
Food Poisoning – Scarlet Fever
Tuberculosis – Whooping Cough
Cholera – Bacterial Meningitis
Syphilis – Pneumonia
Ulcers – Leprosy
Strep Throat – Tetanus
VIDEO CLIP: Understanding Bacteria
Slide13VirusesLiving or Nonliving?
Slide14Viruses
Virology
is the study of viruses
Viruses are “
biological entities
” containing either
DNA or RNA
that
require another cell to survive
.
Viruses have
some
, but not all, of the
characteristics of life
.
*
So
are
viruses
living
or
non-living?*
Viruses seem to exist
only
to make more
viruses!
Slide15Slide16Viral Structure
All viruses have the same basic structure:
Nucleic
acid
core
(DNA or RNA)
Capsid
(Protein coat)
Slide17Slide18How Do Viruses Work?
In order to replicate and make copies of itself, viruses need a
host cell
.
Any living cell
can become a host cell (human, animal, plant, and even bacterial cells!)
Without a host cell,
viruses
cannot funct
ion
(i.e.-are harmless!)
Although any cell can theoretically become a host cell,
specific viruses
will
only
infect
specific cells
(EX: HIV will
only
infect human T cells, a part of your immune system)
Slide19How Do Viruses Work?
Attach:
The capsid of the virus binds to receptor proteins on the surface of a host cell, tricking the host cell into thinking it’s not a foreign invader.
Inject:
The virus then injects its genetic material (DNA or RNA) into the host cell.
Assemble:
The viral genes are expressed, turning the host cell into a virus-making factory.
Repeat:
The host cell eventually bursts, releasing the hundreds of newly formed viruses to infect
surrounding cells!
VIDEO CLIP:
How Viruses
Work
Slide20Viruses
Viruses can cause disease in humans, animals, plants, and even bacteria!
Viruses can cause a variety of diseases:
Common cold – Polio
Hepatitis A, B & C – Influenza
Herpes – Mumps
Mononucleosis – Measles
Warts – Viral Meningitis
Chickenpox – AIDS
VIDEO CLIP:
Viral Disease
Slide21Protection
There are a few big ways to protect yourself against
pathogens
(disease causing agents)
Antibiotics
(drugs to kill bacteria)
Antivirals
(drugs to treat viruses)
Vaccination
(using your body’s own immune system to preemptively guard against attack)
Slide22Antibiotics
Antibiotics can
only
be used to
treat
bacterial infections
!
Target
specific structures
on bacteria to kill them.
First made from a fungus
(penicillin), now most are made
artificially
.
Unfortunately,
antibiotic resistance
(where the antibiotic doesn’t kill the target bacteria anymore) is becoming a
major
problem.
Slide23Antivirals
Antivirals can
only
be used to
treat
certain
viral infections
!
Does
not
“kill” or disarm the virus permanently; only shortens symptoms by 1-2 days.
Usually only prescribed to patients with
life
threatening
symptoms
or those that have a greater chance of
developing
complications
(because of their age or they have a high-risk medical condition).
Just like antibiotics, there is evidence of
antiviral resistance
too!
Slide24Vaccination
Vaccines
can only be used to
prevent
infections (both viral and bacterial) from leading to disease.
“Trick” your immune system to make
antibodies
that destroy
foreign
“bodies” or
particles
(such as bacteria and viruses). Your body remembers how to make these antibodies when the real thing invades.
Made from a
weakened
virus
,
inactivated
virus
, or by using only part of the
virus/bacteria
itself.
VIDEO CLIP:
Vaccination
Slide25Viruses and the
flu
Slide26Slide27To Review....
What are the differences between viruses and bacteria?
Are all bacteria harmful? Explain.
When you get a cold, should you take an antibiotic to help you get better? Why?
What’s the best and easiest thing to do to avoid getting sick?
Slide28http://www.youtube.com/watch?v=3xRttWuf3wQ
Slide29Bacteria
Virus
Both