Sabahat Ateeq
Roll no: 39
Assignment: Microbiology
Submitted to: Madam Saadia
Sexual vs Asexual
• Asexual Reproduction
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involves only 1 parent
offspring genetically identical to parent
involves regular body cells
its quick
• Sexual Reproduction
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involves 2 parents
offspring genetic mix of both parents
involves specialized sex cells
its slow
Asexual Reproduction
• Binary fission
• happens in bacteria, amoeba, some algae
• one parent cell splits into 2 identical daughter cells
• Budding
• happens in yeast, hydra, corals
• parent produces a bud
• bud gets detached and develops into offspring which is identical to parent
Conidia
• Conidia formation takes place in filamentous bacteria like Streptomyces etc., by
the formation of a transverse septum at the apex of the filament .The part of this
filament which bears conidia is called conidiophore. After detachment from the
mother and getting contact with suitable substratum, the conidium germinates and
gives rise to new mycelium.
Budding:
• The bacterial cell develops small swelling at one side which gradually increases in
size Simultaneously the nucleus undergoes division, where one remains with the
mother and other one with some cytoplasm goes to the swelling. This outgrowth is
the bud, which gets separated from the mother by partition wall, e.g.,
Hyphomicrobium vulgare, Rhodomicrobium vannielia, etc.
Cysts
• Cysts are formed by the deposition of additional layer around the mother wall.
These are the resting structure and during favorable condition they again behave
as the mother, e.g., many members of Azotobacter.
Endospore:
• Spores are formed during unfavorable environmental condition like desiccation
and starvation. As the spores are formed within the cell, they are called
endospores. Only one spore is formed in a bacterial cell. On germination, it gives
rise to a bacterial cell.
• Some endospore forming bacteria:
• 1. Gram-positive
• (a) Bacilli
• (i) Obligate aerobes, e.g., Bacillus subtilis, B. anthracis.
Budding: In this case small bud formation from a
parental cell. And daughter cell , finally gets separated
from the parent cell.
FRAGMENTATION:
• This is a form of reproduction where a new organism grows from a
fragment of parent cell. Each fragment develops into in a fully grown
individual.
• Binary Fission:
• It is division of a single cell into two or more cells, and the
regeneration of those cells into separate entities resembling the
original cell.
SEXUAL REPRODUCTION
• Many plasmids can insert into the DNA of the nucleus, and detach
from it. In doing so, the plasmid may leave part of the plasmid DNA
behind, and take some of the nuclear DNA with it.
• SEXUAL REPRODUCTION: plasmids can transfer from cell to cell.
The cells need notbe of the samebacterial 'species'.
• SEXUAL REPRODUCTION:
• Conjugation
• Transformation
• Transduction
CONJUGATION
• one bacterium connects itself to another through a protein tube
structure called a PILUS. Genes are transferred from one bacterium to
the other through this tube.
• TRANSFORMATION
• The bacterium binds the DNA and transports it across the bacterial cell
membrane. The new DNA is then incorporated into thebacterial cell's
DNA.
• TRANSDUCTION
It involves the exchanging of bacterial DNA through bacteriophages.