Download Viruses are the smallest, non living microbes, 10000

Polyhedral Capsid
Helical Capsid
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McGraw Hill, Biology
Viruses are the
smallest, non living
microbes, 10,000
times smaller then
bacteria. Viruses are
genetic material (DNA
and RNA) encased in a
protective coat called
capsid.
Binal Capsid
The reproductive cycle of a bacteriophage occurs in two different cycles depending
on the phage, the Lytic and Lysogenic cycles. During which the virus attaches itself
to the protein outer layer of its host. After penetration, the virus injects the host
with its genomes. The virus’ genetic material is copied within the host. In the Lytic
cycle, the capsid is formed and filled with the new genomes. The cell lyses and
releases the new phages. In the Lysogenic cycle, the DNA of the host cell is copied
with the genomes of the virus. Then binary fission takes place and each new copy
of the genomes remains in both of the new host cells. Until the phage is developed
and ready to leave the host, to begin the cycles again.
The nucleic acid
is protected in a
protein shell
called the capsid.
Theses capsids
vary in shape
and size.