Download bacteria - Pleasantville High School

BACTERIA
What are Monerans?
 Monerans are believed to have existed longer than any
other life form on Earth
 Most monerans are types of BACTERIA
What Do We Know About Bacteria?
 Unicellular organisms:
 One celled organisms
 Do not have a true, membrane bound nucleus
 Can be found almost everywhere
 Some bacterial are bad for you
 Some bacterial are good for you
 Some bacterial will not affect your health at all
What Do Bacterial Look Like?
 Bacterial are usually one of three shapes:
Rods
Spheres
Spirals
How Do Bacterial Reproduce?
 Bacterial reproduce asexually
 Reproduce by dividing in half
 Binary Fission
 Bacterial split into two cells
 Each cell gets an exact copy of the DNA
 Some bacteria can actually reproduce every 20 minutes
Anything Else about Bacteria
 Some contain Chlorophyll and make their own food, we
call them
 Autotrophs
 Others can’t make their own food, we call them
 Heterotrophs
 Some can get their energy from chemicals such as:
 Ammonia and Sulfur
 Others live in odd place like:
 Deep sea vents
 Antarctica
 Hot Springs
What is Their Function?
 Help decompose dead things
 Live in animals’ digestive system to digest food
 They may cause diseases and they are called
pathogens
 Some can be killed off with antibiotics which stop their
reproduction process.
 Others can be prevented by vaccination, a way of
killing bacteria to help the body protect itself against the
live bacteria
 Used in the food making process
 Used to make artificial snow at ski resorts
Name Something Else that Causes
Diseases and Sickness, besides
Bacteria or “Germs.”
 VIRUS!
Properties of viruses
• no membranes, cytoplasm, ribosomes, or other
cellular components
• they cannot move or grow
• they can only reproduce inside a host cell
• they consist of 2 major parts - a protein coat, and
hereditary material (DNA or RNA)
• they are extremely tiny, much smaller than a cell and
only
Review of
DNA
• Shape of a
double helix
•Base pairs held
together by
hydrogen bonds
(weak)
•Repeating units
of nucleotides
Adenine <-> Thymine
Guanine <-> Cytosine
Parasitic Nature
•Obligate intracellular parasites
•Specific to their hosts (human, dog, some can cross
species)
•They can only attack specific cells , the common
cold is a virus that specifically attacks cells of the
respiratory track (hence the coughing and sneezing
and sniffling).
•HIV specifically attacks white blood cells
Bacteriophage a virus that
infects bacteria
Viral Reproduction
 Lytic cycle =
reproduction
occurs, cells burst
 Lysogenic cycle =
reproduction does
not immediately
occur (dormancy)
 Virulent = viruses
that undergo both
cycles
 Viruses multiply, or replicate using their
own genetic material and the host cell's
machinery to create more viruses.
Viruses cannot reproduce outside of the
host.
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Attachment
Penetration - the virus is engulfed by
the cell (Cell can enter Lysogenic or
Lytic Cycle)
Biosynthesis - viral components are
made(protein coat, capsid,
DNA/RNA)
Maturation - assembly of viral
components
Release - viruses leave host cell to
infect new cells(often destroys host)
Retroviruses -- RNA viruses that
have a DNA stage
Human Immunodeficiency Virus - causes AIDS
 Retrovirus (RNA inside a protein coat)
 Reverse Transcriptase makes DNA from the virus RNA
 DNA inserts into host DNA
 Proteins are assembled from the DNA code
 Viruses assembled from the proteins
 Viruses released from the cell
Emerging Viruses
 Emerging Viruses
 illnesses not previously known: AIDS, West Nile Virus,
SARS, Ebola, Bird Flu
 Could be mutations of known viruses
 Could be viruses exposed when new areas were
developed
 Could have jumped species
How Do Vaccines Work?
Once you have gotten a virus, such as chicken pox,
your body develops the immunity to that virus.
2. Vaccines are made by growing a weakened or killed
form of the virus (often grown in eggs)
3. This form of the virus is injected into a person's
body, which causes an immune response, and
immunity to the virus.
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