Download Comparing Viruses and Cells Notes

Comparing Viruses and Bacteria
Pathogens
• Pathogens are anything capable of causing
infectious disease.
Have you ever experienced a
cold or the flu?
• If so, then you have had a close
encounter with a virus.
Are viruses alive?
• What do you know about viruses?
• Did you see them in any of the taxonomic
groupings?
Viruses
Virus: Non-living strand of genetic material
within a protein coat; requires a host
Parasitic
Host: - any organism that is used by a parasite to
complete its lifecycle
Viruses are not considered to be
living because they are not made
of cells and do not exhibit most
of the characteristics of life.
Host specific: - most virus or bacteria will only affect a
single host or a small group of host
species
Viruses attach to
specific sites on
cells called
“docking sites”
West Nile Virus – affects birds, horses, and people
Influenza type B – affects only people not others
Parvo – affects only dogs, not other organisms
Virus Structure:
Capsid
- an outer protein
coat for protection
Glycoproteins
- Used to attach to
the host.
DNA or RNA core (genetic material)
- holds the genetic material that will
affect the host
There may be other components, such as a tail or
fibers, in some viruses
How do viruses affect you?
They blow up the cells that they affect!!
Lysis – to break or rupture cells or cell membranes
There are two different ways
First - Lytic Cycle:
steps
1. Attach
2. Entry
- Virus “docks”
with host cell
- Virus inject it’s
DNA/RNA into host cell
3. Replicate - replication of
and Assemble virus parts
4. Lysis - cell ruptures and
new Virus’ inVade
tissues of the host
Second – Lysogenic Cycle
steps
1. Attach
2. Entry
3. Provirus
Formation
4. Cell Division
5. Stress
6. Replicate and
Assemble
7. Lysis
- DNA attaches to
the cells own DNA
Examples of Lytic Virus infections:
Influenza
Caused by several types
of influenza viruses
HIV/AIDS
Caused by the human
immunodeficiency virus;
This type of virus is
called a retrovirus
because it contains RNA
instead of DNA.
Examples of Lysogenic Virus infections
Chicken Pox - caused by Herpes
Virus
Shingles
- caused by Herpes
Virus
- caused by Herpes
Coldsores/
Feverblisters Virus
Bacteriophage: a virus that
infects bacteria
Bacteriophages can cause scarlet
fever and toxic shock syndrome.
How does your body fight
Viral Infections?
After enough cell debris (from blown up cells)
is detected your Immune system gets
involved.
White blood cells to the rescue!!
Macrophage
-large white blood cells that get rid
of debris by eating it.
When they eat too much, they
die. These dead cells and the cell
debris are “puss”
Other white blood cells pick up viral
particles from the battle and carry it to
Lymph nodes.
In the lymph nodes, they look for cells to fight this
type of virus.
T- cells (thyroid cells) are called upon and go
to the site of the infection to kill specific infected
cells
B-cells (bursal cells) make antibodies that go
to the site and kill free viruses
The virus is “killed” 21 days from first infection
How does your body
fight Viral Infections?
• Immunizations – using vaccines to help the
body gain immunity by introducing small
doses of the infection
• Vaccine: An injection of a killed or
weakened pathogen
• Antibiotics are not used against viruses!
Bacteria!!!!
-unicellular, prokaryotic organisms that sometimes
cause disease
1. Shape
Bacteria come in three shapes.
Cocci - spherical shaped
Bacilli – rod shaped
Spirilla – corkscrew
shaped
Growth of Bacteria:
Binary Fission:
Similar to Mitosis - splitting
Conjugation:
Similar to sexual reproduction.
Passing of genetic material
Spore Formation:
Creating hard coatings to
protect during unfavorable
conditions.
conjugative
connection
spore
Diseases of Bacteria:
1. Coccus diseases
Streptococcus pharyngitis
Strep throat
Neisseria meningitidis
Bacterial meningitis
2. Bacillus diseases
Bacillus anthracis
Anthrax
Yersinia Pestis
Bubonic Plague
3. Spirillum diseases
Treponema pallidum
Syphillis
Borellia burgdorferia
Lyme disease
Bacteria hurt you by………….
Poisoning your cells!!!
Once inside the host, they begin to release
metabolic waste called toxins.
Your Immune system usually cannot fight
bacterial infections alone.
Antibiotics
kill
Bacteria!
Review for test
Define terms
Virus
Host
Host Specific
Capsid
Surface Membrane Proteins
DNA/RNA core
Lysis
Lytic Cycle
Lysogenic Cycle
Macrophage
T-cells
B –cells
Cocci
Bacilli
Spirilli
Antibiotic
Binary fission
Conjugation
Spore Formation
Questions
1. Draw and label both the Lytic and Lysogenic cycles.
2. Draw and give examples of all three types of bacteria.