Download Viral Structure and Life Cycles : Notes - Mr. Lesiuk

Name : ________________
Date : __________
VIRUSES : Viral Structure and Life Cycles : Notes #1
A) Structure of a Virus
-Composed of a core of ______________________________
surrounded by a _____________________________________
______________________
-The Capsid ______________________ the nucleic acid core.
-Nucleic Acid can be _____________________________ but
never both. (retroviruses contain RNA)
-The _________________ helps attach the virus to the cell
-The _______________________the nucleic acid into the cell.
- The picture shown above is that of a _______________________________________
________________________________________________________
- There are three main shapes of Viruses.
See pictures below:
________________
__________________________
______________________
B) Biotic( ___________) or ________________(_________________)
**Viruses straddle the fence between living and non-living
ALIVE
Non-Living
- Have DNA or RNA and _____________
- Acellular – not made of cells
(No non-living thing contains ___________
_____________/protein)
- _________________________
- Can _________________
- _________________________
- Have ____________________
- Do not move
- Can reproduce**
*** Do _____________________
- Demonstrate some level of being able
____________________________
to __________________________________
____________________________
____________________
** Some biologists describe viruses as being non-living infectious particles
C) Viral Life Cycles
- Two main types of Life Cycles (Viral Replication) for viruses:
1) -_________________________
2) -__________________________
1) LYTIC CYCLE OF A VIRUS:
- In the Lytic Life Cycle (shown below),______________________________________
_______________________________________________________________________
_______________________________________________________________________.
_______________________________________This process takes place very quickly.
- Viruses that reproduce through a lytic cycle are _____________________________
__________________________________________
- _____________________________________________________: A virus that makes
many copies of itself in its host cell; _________________________________________
____________and release the reproduced viruses to spread to many more host cells.
- This process only takes about ________________________from beginning to end.
2) LYSOGENIC CYCLE OF A VIRUS
- Another way in which some viruses affect a cell is through a __________________
______________. The virus does not reproduce and lyse of the host cell (as was the
case in the lytic cycle) – at least not right away.
-______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
- Like the Lytic Cycle, the DNA of the virus is injected into the host cell.
- Once integrated into the Host cell’s DNA, the viral DNA is known as
__________________________________________________________________
- The PROPHAGE may remain combined as part of the DNA of the host cell for
many generations. _______________________________________________________
_______________________________________________________________________.
- As long as this prophage (viral DNA) does not cause lysis it is considered to be acting as a ______________________________, sometimes a temperate phage will
get triggered (_____________________________________________) to enter into the
Lytic Cycle. This temperate phage now becomes a ____________________________
_________________________________________