Lect.1 Flashcards
are obligate intracellular parasite
Viruses
composed of only proteinaceous matter responsible for human disease
Prions
Sizes?
Parovirus- 20nm
Poxvirus- 300 nm
Viruses are described as ___ cz they pass through bacterial filters
filterable agents
Capsomeres are subunits that are
bound to covalent bonds to facilities release of genome during replication
____ found on the envelope of viruses can act as legends for virus or have certain activities
Spikes
enveloped viruses are sensitive to ether?
- dissolves lipids present on envelope /lossing its ligand
Loss of envelope led to the loss of infectivity ?
Ligand present on surface is lost
Role of host in virus replication?
Acts as a factory, providing substrates, energy and machinery for synthesis of coat proteins and nucleic acid genomes
Steps of Virus Replication?
- Recognition & Attachment to the target cells
-
Receptor recognition of HIV?
CD4 receptors of the T-helper cells
Receptor recognition of Enveloped Influenza virus?
Hemagglutinin
Viruses may prefer certain target tissue
Tropism
some viruses at neural PH promote cell-to-cell fusion ?
Syncytia
Examples of some viruses at neural PH promote cell-to-cell fusion ?
Measles Paramyxovirus, HIV
The virus is then delivered to the replication site
Uncoating
DNA viruses replicate in the nucleus except:
Proxvirus
RNA viruses replicates in the cytoplasm except :
Retroviruses
penetration aka:
Viropexis
The most important step in virus Replication
Synthesis of Macromols
RNA virus must ______ during the stage of synthesis of Macromols
encode for enzymes which transcript the RNA
What happens to DNA viruses during the stage of synthesis?
DNA Viruses replicate in the nucleus utilizing the cells DNA-dependent RNA polymeraze
replication differs according to the ___
type of the nucleic acid core
____ are released after cell lysis
Naked virus
How are naked viruses released after cell lysis?
Budding
How are viruses ( that acquire their envelope) in the cytoplasm released?
Require cell lyses before released
The time interval after penetration and before assembly
Eclipse
During the eclipse cycle, ______ could not be isolated
Infective Virion
