Viruses have two life cycles: lytic and lysogenic. The lytic cycle involves the replication of viruses within a host cell, forcing it to rapidly produce thousands of identical virus copies. This cycle has five steps: 1) attachment of the virus to the host cell receptor, 2) penetration of viral DNA/RNA inside, 3) protein synthesis using the host cell's machinery, 4) assembly of new viral particles using replicated DNA and proteins, and 5) lysis of the host cell to release new viruses.

2.  Life cycle of viruses affect the cell and infect
them also produce number of new cells .
 Two types of cycles run by viruses.
 Example= lytic cycle and lysogenic cycle.
 In viral life cycle replication of viruses is also
know as lytic cycle.

3.  For replication of viruses host is necessary.
 Host may be bacteria, plants or a animal.
 When viruses infect on host cell, a host cell is
forced to rapidly produced thousands of
identical copies of original virus.
 Types of replication :-
1) Attachment
2) Penetration
3) Protein synthesis
4) Assembly
5) Lysis

5. 1. Attachment :- In this step, virus attached on
surface of host cell, they attached on specific
receptor on plasma membrane of host cell.
2. Penetration :- In this step, virus enter inside the
host cell, (only DNA / RNA of virus enter) here
entry of virus is occurs.
3. Protein synthesis :- biosynthesis of protein take
place in cytoplasm of host cell at same time
replication of viral DNA also perform in host
cell. transcription is important. Here additional
DNA and RNA is form for protein synthesis by
the use of host cell proteins and enzymes.

6. 4. Assembly :- After biosynthesis modified viral
protein are packed with newly replicated
viral genome into new virus that ready for
release from the host cell.
5. Lysis :- In this step viruses burst the cell
membrane of host cell release.
In this way the lytic cycle resemble a small
viruses factory.
Presented by: patil sakshi.