VIRAL S

TRUCTU

RE &

TYPE

S

ET

HA

N W

RI G

HT

, R

AC

HE

L SY

LVI A

, E

MI L

Y

MC

GR

EE

N

STRUCTURE

Three components:

- Capsid (capsomeres)

- Genome (3-5 average, - over 100 expressed proteins)

- Envelope (some have this)

- Viral Envelope-viral glycoproteins- derived from host membrane

Mimivirus! – size of small becteria- Bring questions as to evolutionary history

TYPES OF VIRUSES

- Capsid structure- rod-shaped-polyhedral-or more complex

Host Range

Bacteriophage – viruses that infect bacteria

I’D LIKE TO INFECT YOU WITH MY DNA ;)

;)

Viral Reproduction

TWO MECHANISMS OF REPLICATION BY PHAGES:LYTIC AND LYSOGENIC CYCLES

© 2011 Pearson Education, Inc.

Animation: Phage T4 Lytic CycleRight-click slide / select “Play”

© 2011 Pearson Education, Inc.

Animation: Phage Lambda Lysogenic and Lytic CyclesRight-click slide / select “Play”

EVOLUTION

Replication occurs in host cell

Uses host cell’s organelles to synthesis progeny viruses

Glycoprotein

Reversetranscriptase HIV

Viral envelope

Capsid

RNA (twoidenticalstrands)

HOSTCELL

Viral RNAReversetranscriptase

RNA-DNAhybrid

DNA

NUCLEUSProvirus

ChromosomalDNA

RNA genomefor thenext viralgeneration

mRNA

New virus

HIV

Membraneof whiteblood cell

0.25 -m

HIV entering a cell

New HIV leaving a cell

FIGURE 19.8

PATH

OGENICS

K A R A H E A T H E R T O N , J A K E R O S T , G R I F F I N S C H R O E T E R

Symptoms Severity of the virusVaccineTreatment

VIRAL DISEASE IN ANIMALS & PLANTS

EpidemicPandemic3 factors1. mutations2. spread from humans3. spread from animals

EMERGING VIRUSES

VIROIDS AND PRIONS

I’D LIKE TO INFECT YOU WITH MY DNA ;)

;)

Viral Reproduction

TWO MECHANISMS OF REPLICATION BY PHAGES:LYTIC AND LYSOGENIC CYCLES

© 2011 Pearson Education, Inc.

Animation: Phage T4 Lytic CycleRight-click slide / select “Play”

© 2011 Pearson Education, Inc.

Animation: Phage Lambda Lysogenic and Lytic CyclesRight-click slide / select “Play”

EVOLUTION

Replication occurs in host cell

Uses host cell’s organelles to synthesis progeny viruses

Glycoprotein

Reversetranscriptase HIV

Viral envelope

Capsid

RNA (twoidenticalstrands)

HOSTCELL

Viral RNAReversetranscriptase

RNA-DNAhybrid

DNA

NUCLEUSProvirus

ChromosomalDNA

RNA genomefor thenext viralgeneration

mRNA

New virus

HIV

Membraneof whiteblood cell

0.25 -m

HIV entering a cell

New HIV leaving a cell

FIGURE 19.8

PA

THOLO

GY

K A R A H E A T H E R T O N , J A K E R O S T , G R I F F I N S C H R O E T E R

Symptoms Severity of the virusVaccineTreatment

VIRAL DISEASE IN ANIMALS & PLANTS

EpidemicPandemic3 factors1. mutations2. spread from humans3. spread from animals

EMERGING VIRUSES

VIROIDS AND PRIONS