Cherubim CurayagBSEd – Bio Sci 3

SEXUAL REPRODUCTION

Binary Fission - creates new

bacteria but no genetic

diversity

single DNA molecule replicates and both copies

attach to the cell membrane.

The cell membrane begins to grow

between the two DNA molecules

the cell membrane begins to pinch

inward;cell wall then forms

between the two DNA molecules

dividing the original cell into two

identical daughter cell

BINARY FISSION

SEXUAL REPRODUCTIONSex in bacteria differs somewhat from what we consider

sex in eukaryotes. It involves the PLASMID, which has

several important characteristics:

A plasmid is a loop of DNA. Plasmids

can multiply autonomously within the

cell. Thus we may find from zero to

many of one or more plasmids in each

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 not be of the

same bacterial 'species'.

BACTERIAL RECOMBINATION:

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 the

bacterial cell's DNA.

TRANSDUCTION

involves the exchanging of

bacterial DNA through

bacteriophages.

BACTERIOPHAGES

• viruses that infect bacteria.

There are two types of

transduction: generalized

and specialized transduction.

The End