Why does a RNA virus carry essential enzymes within its particles, whereas DNA viruses do not Why does a RNA virus carry essential enzymes within its particles, whereas DNA viruses do not Solution RNA viruses replicate with the help of RNA-dependant RNA polymerases and need to code for their polymerases as they are not present in animal cells. Therefore once the virus attacks the host. by different means, it creates mRNA for further replication. based on how it creates the mRNA there are different types of RNA viruses. Plus strand viruses: the virion RNA is same as mRNA. So starts translating immediately after infection. example poliovirus Negative-strand RNA viruses: These viruses have RNA complementary to mRNA strands. So require RNA-dependant RNA polymerases and transcribing enzymes. example: influenza virus. double-stranded RNA viruses: These viruses contain double-stranded RNA molecules that cannot function as mRNA. These viruses require RNA polymerases to make their mRNA. example: rotavirus DNA viruses utilize host enzymes for replication and, host tRNA and ribosomes for the synthesis of proteins. These viruses produce specific proteins that are coded by viral genes as compared to normal cells that produce thousands of proteins. these proteins often modify host cell responses to enhance viral replication..

1. Why does a RNA virus carry essential enzymes within its particles, whereas DNA viruses do not
Why does a RNA virus carry essential enzymes within its particles, whereas DNA viruses do not
Solution
RNA viruses replicate with the help of RNA-dependant RNA polymerases and need to code for
their polymerases as they are not present in animal cells. Therefore once the virus attacks the
host. by different means, it creates mRNA for further replication. based on how it creates the
mRNA there are different types of RNA viruses.
Plus strand viruses: the virion RNA is same as mRNA. So starts translating immediately after
infection. example poliovirus
Negative-strand RNA viruses: These viruses have RNA complementary to mRNA strands. So
require RNA-dependant RNA polymerases and transcribing enzymes. example: influenza virus.
double-stranded RNA viruses: These viruses contain double-stranded RNA molecules that
cannot function as mRNA. These viruses require RNA polymerases to make their mRNA.
example: rotavirus
DNA viruses utilize host enzymes for replication and, host tRNA and ribosomes for the synthesis
of proteins. These viruses produce specific proteins that are coded by viral genes as compared to
normal cells that produce thousands of proteins. these proteins often modify host cell responses
to enhance viral replication.