Download LN #12 Viruses

Viruses
LN # 13
What is a Virus?
• Viruses are a lot
smaller than bacteria
or animal cells.
• Unlike cells that are
living, viruses are
nonliving.
• They are unable to
grow and reproduce
on their own and
therefore must infect
cells to do so.
Viral Structure
• Unlike cells, viruses
are NONLIVING.
• Viruses are simple
– DNA or RNA
• Instructions to build
more viruses
– Protein
• Protects the instructions
• The only way a virus
can reproduce is to
infect a cell
Virus Reproduction
• Viruses attach to a specific
type of cell and injects its
nucleic acid into the cell.
• Once inside the viral
nucleic acid takes over the
cell.
• The cell begins to produce
viral nucleic acid and
proteins.
• New viruses are made and
the released.
• The host cell dies.
Viruses and Cells
• Without cells viruses could not reproduce.
• Viruses can infect both prokaryotic and
eukaryotic cells.
• Viruses are specialized; they have one type of
cell they infect.
Prokaryotic Cell
Eukaryotic Cell
Single Celled (Bacteria)
Multi and Single celled
Do Not have Organelles
Have Organelles
Modes of Infection
• Virus may live outside of
the host, until ready to
infect.
• Route of infection for cold
virus
–
–
–
–
Nose
Eyes
Mouth
Nasopharynx
• Once inside the body,
virus will target and infect
a cell.
How to prevent spread
• Wash your hands
• Viruses can be on
–
–
–
–
Phones
Money
Door handles
Anything we touch
• Don’t share drinks or
food.
• Sneeze into your sleeve
or tissue
– Throw away used tissues
Summary
1.
2.
3.
4.
What is a virus?
What must a virus do in order to reproduce?
What are virus made of?
Describe the steps for virus replication (2 or
more sentences.
5. How are viruses and cells different?
6. What are the modes of infection?
7. How can you prevent the spread of viruses?