Transcript The Fugitives and Assassins: Bacteria and Viruses

Pirates of Cells:
Bacteria and Viruses
What I will learn??
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What is a Virus? How do they multiply?
What is bacteria? Where does it exist?
Ways that bacteria spread?
How are bacterial infections and viral
infections treated?
Viruses have no nucleus, no
organelles, no cytoplasm or cell
membrane.
• This is why it does not belong to any kingdom.
What is a virus?
• The Latin name for virus is “poison”.
• They are nonliving pathogens.
• Viruses can reproduce only by infecting living cells.
• Most viruses are small.
• Viruses are particles of:
-nucleic acid: DNA or RNA
-protein coat: called a capsid
• The capsid enables the virus to enter a host cell.
The proteins BIND to receptors on the surface of
the cell and tricks the cell to allowing it inside.
The Virus is inside: What NOW?
Lytic vc. Lysogenic cycle
• Once inside the cell, one of two things can happen:
• 1. The virus can lay dormant (alseep) inside the cell and
not cause the organism to get sick. This is called the
lysogenic cycle. Diseases that “keep showing up” could
be considered lysogenic.
• 2. The virus hijacks the cells normal cellular functions
and tricks the cell into making more viruses. This will
eventually kill the cell and cause more viruses to be
released. This is called the lytic cycle. Diseases that
begin and end over a short period time could be
considered lytic.
Viral Diseases
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Herpes
Warts
Common cold
Influenza (flu)
Chicken pox
AIDS
Lysogenic Cycle
Lytic Cycle
Viral Transmission
• Can you get a viral disease
from touching or sitting on a
surface??
• The only ways that you can
catch a viral disease if from
direct contact, an injection,
inhalation, or spreading
infected body fluids into a cut,
your mouth, nose or eyes.
• Many studies show that by
simply washing your hands
prior to eating, rubbing your
nose or eyes, you can reduce
your chances of getting a viral
infection.
What is Bacteria
• Thinking Question- Are bacteria prokaryotic or
eukaryotic? Why?
Bacteria
• Bacteria are single celled, prokaryotic
organisms.
• Replicates asexually.
• Bacteria can be harmful or beneficial.
• There are two kingdoms of bacteria
Eubacteria and Archaebacteria.
Eubacteria
• The larger of the two
kingdoms of prokaryotes in
the eubacteria.
• Eubacteria live almost
everywhere! In freshwater,
saltwater, on land, and
inside the human body.
• The cell walls of eubacteria
contain a carbohydrate
called peptidoglycan, that
protects the cell and
determine its shape.
Archaebacteria
• They are very similar to
eubacteria except
archaebacteria lack the
carbohydrate pepidoglycan
and different lipids in their
cell membranes.
• Different gene sequences.
• This bacteria can live in very
harsh environments.
• Some can live in oxygen-fee
environments, extremely
salty, or extremely hot
environments.
Identifying Prokaryotes
• Cell shape
• Cell wall
• Movement
Bacteria shape
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Bacilli- rod shaped
Cocci- sphere shaped
Spirilla- spiral shaped
Flagella- tail-like
structures that help
to propel the
bacteria
• Cillia- miniture
flagella surround the
cell that help to
“swim”
Obtaining Energy
• Autotrophs- makes its
own food
• Chemotrophs- gets
nourishment using
chemical energy ExArchaebacteria
• Heterotrophs- obtain
food from eating Ex- E.
coli
Bacteria Reproduction
• Some bacteria
reproduce as fast as
every 20 minutes!!!
• Bacteria reproduce by 3
ways:
• 1.binary fission
• 2. conjugation
• 3.spore formation
Binary Fission
Conjugation
Spore Formation
Why do Bacteria Make us feel Sick?
• Some bacteria produce toxins. These chemicals
are what cause us to have nausea, diarrhea, or
vomiting when we are infected with bacteria. Exfood poisoning
• Some secrete enzymes which destroy our normal
cell’s functions.
• A human’s normal inflammatory response, which
includes a fever, immune system, vaccinations are
effective or ridding the body of the bacteria.
Examples of infections caused by
Bacteria:
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Dental cavities
Turberculosis
Acne
Salmonella
Straph
Strep
Antibiotics
• Anti= against
• Biotic= living
• So this means that antibiotics will only kill
living things!
• When people get sick with a virus, taking
antibiotics will not help them.