Viruses

Viral Genome

Viral Diseases

Viral Struture

Viral Cycles

Provirus

Evolution

Retrovirus

Animals

Prions

Plants

Emerging Diseases

Capsid

Bacteriophages

Viral Envelope

Lysogenic

Lytic

Only 20nm

nucleic acid enclosed in a protein coat

can have a variety of different genetic material

RNA double strand

Dna single strand

DNA double strand

RNA single strand

Host cell phospholipids and membrane proteins

Proteins and Glycoproteins

Derived from membrane of host cell

Viral enzyme molecules inside their capsids

An accessory structure that helps virus infect the host

Glyco proteins is a protein with a carbohydrate contently bonded

The protein shell that enclosesa viral genome

polyhedral

complex shapes

rod shaped

Built from protein subunits called Capsomeres

The different kinds of proteins is small

called helical viruses

adenoviriuses

Triangular facets

icosahedral viruses

viruses that infect bacteria

T1-T8 phages

T2,4,6 are the T even phages

elongated icosahedral heads

protein tail piece with fibers

also called phages

the host cell dies

at the end the bacteria cell lyses and releases the new phages

Virulent Phages only reproduce by the lytic phase

injects DNA and degrades host DNA

synthesis of viral genomes and proteins

assembly of phages

cell lysis and releases phages

attatches by binding to surface proteins

Replication of phages without destroying host cell

Phages that can do both lytic and lysogenic are called Temperate Phages

The viral DNA integrated in the host DNA is known as a prophage

Lysoggenic means they are capable of activating the prophages and starting a lytic cycle

Phage attatches

Injects DNA

Dna is integrated into host DNA

Reproduces normally

Large pop of bacteria with prophages

Restriction Enzymes

restrict phages ability to replicate within the bacteria

bacteria have defense against phages so they dont go extinct

CRISPRS

DNA sequence that has phage DNA in the spacers

CAS are the nucleases proteins that identify and cut up phage proteins

Animal viruses with the most complicated replicative cycles

Reverse Transcriptase

Transcribes RNA > DNA

this is backwards of normal DNA >RNA so its referred to as Retro or backwards

HIV (Human Immunodeficiency syndrome)

a retrovirus of medical importance

HIV turns into AIDS once the infection sets deep

Enveoped viruses that have two molecules of single strand RNA and two molecules of reverse transcriptase

HIV replicative cycle

reverse transcriptase molecules released

viral DNA is synthesized and enters the cells nucleus

Enters cell

integrates into DNA

permanent in the cell

reproduces and creates more

integrated viral DNA in a host cell

never leaves

contrasts prophages that can leave the cell

can infect any form of life

bacteria archaea fungi algae protists

believed to have evolved from bits of nucleear acids

Plasmids

Transposons

small circular DNA molecules found in bacteria

DNA segments that can move around in the cells genome

Plasmids Transposons and Viruses are all mobile genetic elements

Could have evolved and been the original source of viruses

Vaccines

A harmless piece of pathogen that the immune system can kill so it knows how to defend itself

many diseases were eradicated or greatly reduced using vaccines

measles

polio

smallpox

Viruses that suddenly become apparent are called emerging viruses

HIV/AIDS is an example of an emerging virus

west nile virus

ebola

Pandemic

Epidemic

a widespread outbreak

A worldwide outbreak

Existing viruses mutate and immunity of the old disease is uesless

most have RNA genome

Horizontal Transmission

Vertical Transmission

external viral source

inherits viral load from parent

Proteins that cause degenerative brain disease

scrapie

mad cow disease

prions act very slowly, ten years before symptoms

virtually indestructible

no known cure

Prions are misfolded proteins in the brain

converts other healthy proteins and forms a chain