State Standard

SB3D. Compare & contrast viruses with living organisms.

Viruses (18.2)

Viruses—An Exception A virus is a nucleic acid (__________)

surrounded by a protein coat (__________).

Viruses are _______________, nor are they made of cells.

Viruses __________________ without a __________ cell.

Viruses __________ the machinery needed to carry out the functions of life.

Because viruses are __________, they usually are not placed in the biological classification system.

Why aren’t they considered to be living?

More virus traits…

the core can be made of _____ or _____ (but never both!)

very __________ NOT __________ Can reproduce by

__________ living cells. The capsid helps the

virus __________ to the host cell.

E. Coli and E. Coli and the the

BacteriophagBacteriophagee

What it looks like in What it looks like in real lifereal life

There are two types of viral infection cycles:•__________ (Active)•__________ (Dormant)

Lytic (active) InfectionLytic (active) Infection Virus Virus ____________________ the host cell. the host cell. Virus makes Virus makes ____________________ of itself. of itself. The new copies cause the cell to The new copies cause the cell to ____________________..

TheThe

LyticLytic

CycleCycle

Lysogenic (dormant) InfectionLysogenic (dormant) Infection A virus A virus ____________________ its DNA into the DNA of its DNA into the DNA of

the host cell.the host cell. The virus’s The virus’s ____________________ is is ____________________ (copied) (copied)

along with the host cell’s DNA.along with the host cell’s DNA. The cell does NOT The cell does NOT ____________________ immediately. immediately. Certain conditions can cause the Certain conditions can cause the ____________________

virus to virus to ____________________ to an active lytic cycle. to an active lytic cycle.

                                   

                             

TheThe

LysogenicLysogenic

CycleCycle

Viruses often cause observable Viruses often cause observable ____________________

Antibiotics are Antibiotics are ____________________ against against viruses, because viruses are not viruses, because viruses are not ____________________

Ex. Ex. AIDSAIDS, , SmallpoxSmallpox, , PolioPolio, , MeaslesMeasles, , the the Common ColdCommon Cold

Vaccines Since viruses can’t be cured, our only

defense against them is __________ We accomplish this through the use of

__________ Vaccines contain a __________ or

__________ form of the virus that is __________ into the body.

Retrovirus

Changes DNA into __________

Mutates quickly And example of

a Retrovirus is __________