Download Viruses -Virus : obligate intracellular parasites .

Viruses
-Virus : obligate intracellular parasites .
-Virus contain two genomes DNA or RNA But not both .
which contain :- ss : single stranded . ds : double stranded
-Capsid :- protein shell that enclose the viral genome .
-Capsid symmetry : (( cabic – helical – complex ))
-Viral Enveloped : help in infect host and composed of lipid bilayer and glycoprotein
-Bacterophage :- viruses that infect bacteria cell ( prokaryotic )
-Virion :- complete virus particle : nuclic acid + protein . it is extracellular phase of
virus (( before virus enter host cell ))
-Vector virus passed from host to host through direct contact and vector .
-Nucleocapsid :- viral nucleic acid + protein coat .
-Viroids : is naked circular single strand RNA that infect plants . it is the smallest
known pathogens .
-Prions :- is infectious proteins cause brain disease e.g :- mad cow and CJD in human
.
-DNA viruses replicate in nucleus of host except " poxvirus "
-RNA viruses replicate in cytoplasm except " influenza & retrovirus "
-most plants viruses are RNA viruses .
-Virus may be :- monomorphic , dimorphic , pleomorphic .
-Reproductive in virus :- by assembly of individual components .
-
-Viral Replication Steps :1- Recognition of target cell .
2- Attachment
3- penetration :- By Endocytosis .
4- uncoating
5- replication
6- assembly
7- budding
8- release
DNA viruses :1-Poxviridae
2-herpesvirdiae
3-adenovirdiae
4-hepadnavirdiae
5-papilomavirdiae
6-parvovirdiae
7-polyomvirdiae
RNA viruses :1-picornavirdiae
2-coronavirdiae
3-retrovirdiae
4-reovirdiae
5-orthomyxovirdiae
6-paramyxovirdiae
7-rhabdovirdiae
Some viruses with their causes :1- HIV : AIDS
2- Hantvirus : HPS
3- Ebolavirus :- hemorrhage fever .
4- nipah virus :- encephalitis " binflammation of brain "
5- coronavirus :- SARS " sever acute respiratory syndrome "
-Some Viruses Transmitted :- viruses transmitted by inhaled droplet -----} rhinoviruse
- viruses transmitted by food and water -----} Hep A
- viruses transmitted by direct contact -------} HIV
- viruses transmitted by bite of vector -------} Yellow fever virus .
Calss
DS DNA :1- PAPILLOMAVIRUS
2-POLYOMAVIRUS
3-ADENOVIRUS
4- HERBSVIRUS
Diseases
5- POXVIRUS
6-HEPADNAVIRUS
Papilloma & genetal cancer .
Tumers
Respiratory disease
Herbes + chicken pox , E.G of herpes
virus is :- Epstein – barr virus
Small pox + cow pox
Hepatitis
SS DNA :1-PARVOVIRUS
Rosella
DNA Viruses
Single stranded
(( non enveloped ))
Double Stranded
Enveloped
Herpesviridae
Hepadnavirdiae
Complex enveloped
Non enveloped
Circular
Linear
Papillomavirdiae
Polyomavirdiae
Adenovirdiae
Parvoviridae
Poxvirdiae
Calss
DS RNA :1- Reovirus
SS RNA :1- picornavirus
2- togavirus
Example
Diseases
-
Diarrhea (( gastrointestinal
Respiratory diseases .
1- poliovirus
2- rhinoviruses
3- entericvirus
Rhinoviruses cause :
rhinitis ( common cold )
1- Rubella virus
2- Yellow virus
3- Encephalitis virus
Rubella cause : Rubella
and germany measles .
3- rhapdovirus )) ‫(( السعار‬
-
Rabies .
4- paramyxovirus
-
Measles - MUMPS
5- orthomyxovirus
Influenza virus
Influenza A-B-C
6- Retrovirus
HIV
(( RNA tumor virus ))
AIDS
7- cornavirus
-
SARS
-Oncogenes :- gene that cause cancer .
Oncogenes viruses :- virus that cause cancer , include :1- Epstein –Barr Virus ( Herpes Virus ))
2- Heb B
3- Heb C
4- HTLV
5- Papilloma viruses
-Mutation :- during replication of DNA , copying errors of viral genome maybe
occur .
-Transduction:- transfer of genetal information from one bacterium to another by
bacteriophage .
-Transformation :- is the process by which bacteria take up fragment of naked DNA
and incorporation then into their genome .
-transposition :- mobile genetic elements that can transfer DNA within cell from one
position to other .
-Amplification :- Production of multiple copies of gene .