Transcript If it is not alive, We can’t kill it --...

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 Viruses
 PROTEIN COAT CALLED A CAPSID
 SOME 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
Bacteriophage
Tobacco
Mosaic
Virus
thatVirus
infects a bacteria
Do not harm humans
First virus discovered in tobacco plants.
Does not harm humans.
Influenza
Common flu
Adenovirus
Can affect birds and humans
Common flu
Can cause epidemics- Spanish Flu
Respiratory system infection
Not serious
Figure 19-10 Lytic and Lysogenic Infections
Viral reproduction: Lytic Cycle
reproduction:
Lysogenic
Host range: infection ofViral
a limited
range of host
cells Cycle
(receptor molecules on the surface of cells)
Genome replicated w/o destroying the
The lytic cycle:
host cell
1- attachment
2- injection
Genetic material of virus becomes
3- hydrolyzation
incorporated into the host cell DNA
4- assembly
(prophage DNA)
5- release
Results in death of host cell
Temperate virus
capable of using
Virulent virus (phage reproduction
only (phages
by the lytic
the lytic and lysogenic cycles)
cycle)
May give rise to lytic 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 transcriptase
 Inserts DNA into host cell
 Can lay dormant for years
 Has been linked to cancer
Lysogenic
Lytic
Vaccines
 Biological preparation that improves immunity
 Contains an agent that resembles a virus/disease
causing microorganism
 Stimulates immune system to recognize and destroy