PG AND RESEARCH DEPARTMENT OF MICROBIOLOGY - SRI PARAMAKALYANI COLLEGE - ALWARKURICHI

1. REACCREDITED WITH B GRADE WITH A CGPA OF 2.71 IN THE SECOND CYCLE OF NAAC
AFFILIATED TO MANOMANIUMSUNDARANARUNIVERSITY,TIRUNELVELI.
POST GRADUATE & RESEARCH CENTRE
DEPARTMENT OF MICROBIOLOGY
(Government Aided)
ACADEMIC YEAR 2021-2022
II SEM : VIROLOGY (ZMBM23)
UNIT-2
LYSOGENIC CYCLE
Submitted to,
GUIDE: Dr.C.MARIAPPAN, Ph.D,
ASSISTANT PROFESSOR,
SRI PARAMAKALYANI COLLEGE,
ALWARKURICHI.

2. OBJECTIVES OF PRESENTATION
 To know the complete information about lysogenic cycle .
 To improve the communication and presentation skill.
 To teach the entire concept of lysogenic cycle.

3. SYNOPSIS
 VIRUS
 BACTERIOPHAGE
 STRUCTURE
 LIFE CYCLE OF BACTERIOPHAGE
 LYSOGENIC CYCLE
 STEPS INVOLVED
 PENETRATION
 REPLICATION
 CELL DIVISION

4. VIRUS
 Viruses are non cellular infectious entities which contain either
DNA or RNA normally encased in proteinaceous coat and
reproduce only in living cells.

5. BACTERIOPHAGE
 A bacteriophage also known as a phage is virus that infects and
replicates within bacteria and archaea.
 Bacteriophage was discovered independently by Friedrick Twort in
1915 and Felix D.Herelle in 1917.
 It is basically a type of virus.

6. STRUCTURE

7. LIFE CYCLE OF
BACTERIOPHAGE
 There are two cycles involved in replication of bacteriophage.
1.lytic cycle
2.lysogenic cycle

8. LYSOGENIC CYCLE
 Lysogenic cycle, is one of two cycles of viral reproduction.
 It is characterized by integration of the bacteriophage nucleic acid
into the host bacterium’s genome or formation of a circular
replicon in the bacterial cytoplasm.
 The genetic material of the bacteriophage, called a prophage.
 Lysogentic cycles can also occur in eukaryotes, although the
method of DNA incorporation is not fully understood.

10. STEPS OF THE LYSOGENEIC CYCLE
PENETRATION
REPLICATION OF
GENETIC
MATERIAL
CELL DIVISION

11. PENETRATION
 Once the virus’s genetic material is inserted, it attaches itself to that
of the host’s.
 Some viruses may not immediately start multiplying or replicating
after infecting the cell.
 In case it does not start replicating, the virus is said to be dormant.

12. REPLICATION OF
GENETIC MATERIAL
 Thereafter, the cell will fall back into its regular metabolite
activities and eventually prepare for cell division.
 The genetic material or nucleic acid replicates, and the
nucleus divided into two parts.
 Each part having the same genetic information.

13. CELL DIVISION
 The cell organelles will be replicated followed by division of
the cell body, resulting in two daughter cells.
 Each having virus’s genetic information incorporated to their
genetic material.
 The cells have uter normally until the virus is triggerd.
 This daughter cells carrying the viral genetic material are
known as lysogenetic cycle.

15. REFERENCES
 www.wikepedia.com
 www.microbenotes.com
 www.pubmed.com
 www.sciencedirect.com
 www.vikaspedia.com
 www.slideshare.com

16. SKILLS GAINED
 Communication skills.
 Confidence.
 Gained subject knowledge better.
 Presentation skills.
 Searching capability increased.
 Learn time management.