Download Viruses and Bacteria

Viruses and Bacteria
Chapter 18 Notes to replace Section
Assessments and Chapter Reviews
Summer School
CP Biology
What is a Virus
 Viruses are non living cellular material that
requires a host to survive.
 Very very small
 Contain an inner core of RNA or DNA called a
Capsid that contains genetic instructions that
can only work if injected into a host cell.
 There are 4 different shapes.
 Draw and label each shape on pg. 548-549
Enveloped, Helical, Polyhedral and Bacteriophage
Viral Attachment and Replication
 Viruses are host specific and must find the
correct receptor point on the plasma
membrane of the host cell. (Similar to a lock
opened by a specific key)
 Replication occurs once the Virus injects the
host cell with it’s genetic information.
 Draw the lytic cycle on page 550 and label
the steps.
HIV
 HIV is a virus that attacks Human white blood
cells. It is a retrovirus (RNA in virus)
 Can have a dormancy of many years
 A person infected with the HIV virus will die
from some other illness because the HIV
attacks and kills the white blood cells (which
attack and kill pathogens in the body)
 Some viruses cause cancer or tumors. Warts
are an example of a tumor created by a Virus.
Bacteria
 Archebacteria- Ancient bacteria that live in
very extreme conditions on earth. Called
Extremeophylls (lover of extreme conditions)
 Eubacteria- Use energy and have nutritional
needs (heterotrophs)
 Some Eubacteria can photosynthesize and
some can chemosythesize (hydrothermal
vents)
Structure of a bacteria
 No membrane bound
Time in
organelles (prokaryotic) Minutes
 Draw and label the
0
parts of the typical
20 min
bacteria from page 557.
40
 Bacteria reproduce by
60(1 hour)
fission (splitting into two 80
genetically identical
100
halves) some can do
120 (2 hrs)
this every 20 minutes
140
# of Bacteria
1
2
4
8
16
Bacterial shapes
 3 basic shapes of bacteria: Spherical, Rodlike and
Spiral
 Draw the picture of each from page 556
 Bacteria can be aerobic (Require Oxygen) or
anaerobic (Do not require Oxygen)
 Some bacteria can survive for a very long time by
creating an Endospore which contains the Bacteria’s
DNA and a small amount of its cytoplasm.
 The endospore can withstand extreme temperatures
and conditions until the conditions become better
suited for the spore to germinate and become a
bacteria again.
Bacteria’s importance
 Benefits of Bacteria are:
 Nitrogen Fixing (in essence it helps fertilize for plants




by taking Nitrogen from the atmosphere and making
it available to life)
Bacteria are a primary decomposer that recycles
nutrients.
Many foods and medicines we eat and use rely on
Bacteria such as Swiss cheese and Bacteria
We can splice genes into a bacteria to produce
products like human insulin
Bioremediation using bacteria to break down
pollutants in the environment
Bacterial Diseases
 Many Bacteria cause infections and diseases
such as Strep throat, Staph infection, Tetanus
and cavities
 These can usually be treated with antibiotics
that attack the specific type of bacterial cell
wall or Capsid it has.