Can anyone explain the common steps and differences of virus synthesis in simpler terms? I am most confused about the steps of viral synthesis within the host’s cell. How does it differ between viruses that contain different types of RNA and DNA (ex. ss-, ss+ or ds). Solution In virology, mRNA is said to be plus (+) configuration and its complement is said to be minus (-) configuration. Positive strand viruses begin with translation to produce replicase. However they only make more positive than negative strand so it can\'t act as template (primer-like Ad) eg poliovirus Difference between ss (single stranded) and ds (double stranded) virus is that in ds RNA cell has no enzyme to transcribe RNA into mRNA. Virus carries its own polymerase. eg. Picornaviridae, Caliciviridae. In ss RNA (having +polarity) cell carries RNA-dependent DNA polymerase. dsRNA is transcribed to mRNA by host cell polymerase. eg. retrovirus -ssRNA using viral RdRP (RNA dependent RNA polymerase) makes +ssRNA. This ssRNA makes viral proteins using host ribosomes. On other hand +ssRNA using this viral RdRP makes - ssRNA and also viral proteins. Virus synthesis in host cells can be described in following steps: 1. attachment and adsorption of virus to its host cell 2. penetration and uncoating of virus cover in the host cell 3. early viral mRNA synthesis and protein synthesis like polymerase enzyme 4. replication of viral genome 5. late viral mRNA and protein synthesis (maturation) 6. self-assembly and release of newly formed virus from the host cell as infectious particle.

1. Can anyone explain the common steps and differences of virus synthesis in simpler terms? I am
most confused about the steps of viral synthesis within the host’s cell. How does it differ
between viruses that contain different types of RNA and DNA (ex. ss-, ss+ or ds).
Solution
In virology, mRNA is said to be plus (+) configuration and its complement is said to be minus (-)
configuration. Positive strand viruses begin with translation to produce replicase. However they
only make more positive than negative strand so it can't act as template (primer-like Ad) eg
poliovirus
Difference between ss (single stranded) and ds (double stranded) virus is that in ds RNA cell has
no enzyme to transcribe RNA into mRNA. Virus carries its own polymerase. eg. Picornaviridae,
Caliciviridae. In ss RNA (having +polarity) cell carries RNA-dependent DNA polymerase.
dsRNA is transcribed to mRNA by host cell polymerase. eg. retrovirus
-ssRNA using viral RdRP (RNA dependent RNA polymerase) makes +ssRNA. This ssRNA
makes viral proteins using host ribosomes. On other hand +ssRNA using this viral RdRP makes -
ssRNA and also viral proteins.
Virus synthesis in host cells can be described in following steps:
1. attachment and adsorption of virus to its host cell
2. penetration and uncoating of virus cover in the host cell
3. early viral mRNA synthesis and protein synthesis like polymerase enzyme
4. replication of viral genome
5. late viral mRNA and protein synthesis (maturation)
6. self-assembly and release of newly formed virus from the host cell as infectious particle