Not the Virus!If it is not alive, We can’t kill it -- We can only wish to

contain it!

What the heebie geebies is this?

Major Components of ALL VirusesPROTEIN COAT CALLED A CAPSIDSOME TYPE OF NUCLEIC ACID

What is the main difference between bacterial viruses and animal viruses?

How the nucleic acid enters the host cell

INJECTION VS. ENGULFMENT

PROK ANIMAL

Tobacco Mosaic Virus

First virus discovered in tobacco plants. Does not harm humans.

AdenovirusCommon fluRespiratory system infectionNot serious

InfluenzaCommon fluCan affect birds and humansCan cause epidemics- Spanish Flu

BacteriophageVirus that infects a bacteriaDo not harm humans

Figure 19-10 Lytic and Lysogenic Infections

Viral reproduction: Lytic CycleHost range: infection of a limited range of host cells (receptor molecules on the surface of cells)The lytic cycle: 1- attachment2- injection3- hydrolyzation4- assembly5- releaseResults in death of host cellVirulent virus (phage reproduction only by the lytic cycle)

Viral reproduction: Lysogenic Cycle

Genome replicated w/o destroying the host cell

Genetic material of virus becomes incorporated into the host cell DNA (prophage DNA)

Temperate virus (phages capable of using the lytic and lysogenic cycles)May give rise to lytic cycle

DNA VIRUS CYCLE

HERPES!!!!!!!! Is it in you?!

After the initial infection, some experience sporadic episodes or outbreaks.

Caused by STI and fluid contact

Only transmitted during outbreak or with sores…hard to transfer during latency

Reverse transcriptase Use enzyme reverse transcriptase to

transcribe RNA into DNA

Retroviruses Contain reverse transcriptaseInserts DNA into host cellCan lay dormant for yearsHas been linked to cancer

RETROVIRUS CYCLE

Lysogenic Lytic

VaccinesBiological preparation that improves

immunityContains an agent that resembles a

virus/disease causing microorganismStimulates immune system to recognize and

destroy