Virus

• Viruses are nonliving particles that have a nucleic acid core and a protein-containing capsid.
• To replicate, a virus must first recognize a host cell, than attach to it, and finally enter thehost cell and take over its metabolism.
• During a lytic cycle, a virus replicates and kills the host cell. In lysogenic cycle, a virus’s DNA is integrated into a chromosome of the host cell, but thehost cell does not die.
• Retroviruses contain RNA. Reverse transcriptase in an enzyme that helps convert viral RNA to DNA, which is then integrated into the host cell’s chromosome.
• Virusesprobably originated from their host cells.

Chapter Assessment 18.1

1. It is because it depends in a living thing.
2.
3. A vital virus that enters the DNA chromosomes and replicated in the host cell4. Retroviruses contain reverse transcriptase; it converts the RNA to DNA that goes to the host´s chromosomes.

Vocabulary

Virus: disease-causing non-living particles composed of an inner core ofnucleic acids surrounded by a capsid replicated inside living cells host cell.
Host cell: living cell in which a virus replicates.
Bacteriophage: also called phages viruses that infect anddestroy bacteria.
Capsid: An outer coat protein that surrounds a virus inner core of nucleic acid arrangement of capsid proteins determines the virus shape.
Lytic cycle: viral replication cycle in whicha virus takes over a host cells genetic material and uses the host cell structure and energy to replicate until the host cell bursts killing it.
Lysogenic cycle: viral replication cycle in which thevirus nucleic acid is integrated into the host cell chromosomes a provirus is formed and replicated each time the host cell reproduces the host cell is not killed until the lytic cycle isactivated.
Provirus: viral DNA that is integrated into a host cells chromosome and replicated each time the host cell replicated.
Retrovirus: type of viral replication where a virus uses reverse...