Transcript Viruses - Cloudfront.net

Viruses
and
Bacteria
Viruses
• A virus is a piece of hereditary material (RNA or
DNA) that is covered by protein that infects and
reproduces in living cells.
• Viruses are not considered living things because
they are unable to reproduce on their own: they
require a host cell.
• Viruses are extremely small, much smaller than
bacteria cells.
• Active Viruses: The virus enters a host cell and
become active right away by causing the cell to
make new virus particles.
LABEL
ACTIVE VIRUSES:
A: Viruses attach to cell.
B: DNA/RNA injected into cell
C: Virus takes control of cell & makes
new virus particles.
D: Cell bursts open releasing 100’s of
viruses to infect more cells.
• Latent Viruses: The virus enters the host cell and
becomes a part of the cell’s DNA without
destroying the cell or making new virus particles.
The virus can hide for years before it becomes
active.
• Viral Diseases: Viruses can cause STDs. There are
no antibiotic medications to cure viral diseases.
Viral diseases can be prevented by vaccines.
• Parts of a virus are: DNA/RNA & protein
LABEL
LATENT VIRUSES
A: Attach
B: Virus becomes part of cell’s DNA.
C: Cell divides.
D: Virus becomes active.
E: New viruses are made.
F: Cell breaks open releasing new viruses.
BACTERIA
• All bacteria belong to the Kingdom monera.
• Bacteria are one-celled organisms that do
not have a nucleus.
• Bacteria reproduce by a process called
fission - when a parent cell splits to produce
two new cells that are exactly alike.
• Some bacteria can also reproduce sexually by
lining up beside each other and exchanging
DNA. This process produces a cell that is
different than the parent cells.
• Bacteria are everywhere- in the
food you eat, in the air you breathe,
and millions live in your body.
• Most bacteria are beneficial to us:
however, some can cause disease.
• Many bacteria can cause STDs.
• An organism, such as bacteria, that
can cause disease is called a
pathogen.
• Diseases caused by bacteria are
usually treated with antibiotics.
• An antibiotic is a substance produced
by one organism that inhibits or kills
another organism.
• For example, penicillin prevents
bacteria cells from forming cell walls
so they cannot survive.
• Some diseases can be prevented by
vaccines.
• A vaccine is made from damaged or
killed bacteria.
• Vaccines are injected into the body
so that the white blood cells can
recognize the bacteria.
• If they ever come in contact with the
bacteria again, they can immediately
attack and kill them.
• Parts of a Bacteria: cytoplasm, cell
membrane, cell wall & Flagella,
capsule, DNA
THE END