Download Virus

Endosymbiotic Theory
•
Endosymbiotic Theory proposes that
eukaryotic cells arose from living
communities formed by prokaryotic
organisms.
•
Endo- means inside
• -symbiotic means relationship
Endosymbiotic Theory
•
Prokaryotes entered ancestral eukaryotes
•
Prokaryotes did NOT act as a parasite by infecting
the host (eukaryote)
•
Eukaryotes did NOT digest the prokaryotes
•
Instead, the smaller prokaryotes began LIVING
inside the larger cell – giving rise to eukaryotes
Endosymbiotic Theory
• 1st - Mitochondria & Chloroplasts have DNA
similar to bacterial DNA.
• 2nd – Mitochondria & Chloroplasts have
ribosomes whose size & structure resembles
those of bacteria.
• 3rd – Like bacteria, Mitochondria & Chloroplasts
reproduce by binary fission when the cells
containing them divide by mitosis.
Click Here For Animation Tutorial
Clicker Question #17
Which of the following summarizes the
Endosymbiotic Theory?
a. Mitochondria & chloroplasts in
eukaryotes were once prokaryotes
b. Ribosomes & lysosomes in eukaryotes
were once prokaryotes
c. Mitochondria & chloroplasts are now
found inside prokaryotes
d. None of the above
Clicker Question #18
Which of the following are true?
a. Mitochondria has DNA similar to
prokaryotes
b. Ribosomes in eukaryotes are similar to
prokaryotes
c. When mitochondria create more of
themselves, they divide similar to how
prokaryotes divide
d. All of the above
Viruses
• Virus comes from the Latin word for “poison”
• Virus are particles of nucleic acid, protein, and in
some cases lipids that can reproduce only by infecting
living cells.
• Viruses are so small that they can only be seen using
an electron microscope.
Flu Virus
Ebola Virus
AIDS Virus
Bacteriaphage
Viruses
• Viruses have NO organelles!
• A typical virus is composed of a core of either
DNA or RNA surrounded by a protein coat.
Common Cold Virus
Small Pox Virus
Polio Virus
Herpes Virus
Viruses
• A virus’s outer protein coat is
called its capsid.
• A capsid is an outer protein
coat that enables a virus to enter a
host cell.
• The capsid binds to the surface of
a cell and “tricks” the cell into
allowing it inside.
Viruses
• Once inside the cell, the viral genes take over.
• The cell transcribes (reads and copies) the
viral genes, putting the genetic program of the
virus into effect.
• And often times the virus destroys the host
cell
Viruses
Vaccine: A preparation
of a weakened or killed
pathogen, upon injection, stimulates antibody
production or cellular immunity against the pathogen
but is incapable of causing severe infection (sickness).
• A world wide vaccination program was able to
eliminate smallpox!
• Antibiotics NEVER cure viral infections!!...ONLY Bacteria
Click here to compare
size!
Small pox
Viruses Video
Viruses
Bacteria
(cells)
• Reproduces on their own
• Has organelles
• Large in size
• Cell wall for protection
Both
• DNA or RNA
• Cause disease
• Must have host to reproduce
• Has NO organelles
• Extremely small in size
• Capsid for protection
Clicker Question #19
Which of the following statements is
true about viruses?
a.
b.
c.
d.
Viruses do not have DNA
Viruses must have a host to reproduce
Antibiotics kill viruses
Viruses have organelles
Clicker Question #20
Which of the following is the
smallest?
a. White blood cell
b. Pollen
c. Bacteria
d. Virus
Clicker Question #21
Which of the following do viruses
NOT have?
a. Organelles
b. Capsid
c. Genetic material
d. They have all of the above
Clicker Question #22
DNA is located here:
a.
b.
c.
d.
Chloroplast
Nucleus
Lysosomes
Vacuoles
The End