Bacteria produce one or more branches. Branches separate and live independently.

Bacteria are divided into one or more fragments for various reasons. Each fragment develops into a complete bacterium.

Bacteria form small buds. First a small bud emerges on one side. Then the nucleus gradually enlarges on one side and the nucleoid material of the original bacterium splits into two parts on the other. A fragment of nucleoid material enters the bud. The bud grows larger and splits off. For example, Ancalomicrobium adetum.

(i) At the beginning of bifurcation bacteria grow in size by consuming food. Its nucleus is also enlarged.
(ii) Bacterial DNA is located in the center of the cell and associated with the cell membrane.
(iii) Replication of DNA takes place while attached to the cell membrane.
(iv) The cell grows in length. Growth of the cell wall and cell membrane occurs between the two ends of the cell.
(v) Cell wall and cell membrane elongation causes DNA replicas to separate in two directions.
(vi) The cytoplasm of the cell folds inwards. The nucleus then divides into two fragments. The cytoplasm folds further inward. Later the cytoplasm changes into two cells with nucleus.
(vii) Due to the turgor pressure, the newly formed daughter cells separate from each other.
(viii) The daughter cells grow to equal the mother cells. Again takes part in bifurcation. This process takes 20-30 minutes.

Numerous fine hair-like appendages arise from the outer layer of gram negative bacteria. These are called pili or fimbriae. It is more numerous than flagella and shorter in length. It is made up of proteins called pilin. Conjugation tubes are formed during reproduction and are called sex pili. Gonorrhea bacteria attach to host cells by pili.

The whip-like appendages that arise from the outer layer of the cytoplasm are called flagella. The stiff flagella are called fimbriae. It is composed of flagellin protein. Its length is 4-5 nm. Flagella help bacteria to move. Each flagella has three segments. Basal body, hook and filament. Bacteria with flagella are called Tricus and those without flagella are called Atrichous.

Bacterial cells do not have a true nucleus. Its nucleus is called nucleoid or xenophore or pseudonucleus. It lacks nuclear membrane and nucleolus. The center of the cytoplasm contains a single stranded double-stranded DNA. At the center of DNA is a circular RNA. RNA is surrounded by nucleoproteins. It does not contain histone proteins. It transfers hereditary traits from generation to generation.

The colorless part of the cell surrounded by plasma membrane is called cytoplasm. The parts of cytoplasm are:
(i) Ribosomes: 70S ribosomes are located freely in the cytoplasm of the cell. It is made up of proteins and RNA. It contains 30-50% protein and 50-70% RNA. Each bacterium contains 10,000-20,000 ribosomes. It synthesizes proteins for cells.
(ii) Chromatophore : Cytoplasm of bacteria contains hollow spherical chromatophore. It contains bacteriochlorophyll. It helps in photosynthesis.
(iii) Volutin : The cytoplasm of young bacterial cells contains small granular volutin. With the increase of age, it turns into cell cavity. It stores food for cells and transports phosphate.
(iv) Cell cavity: Cell cytoplasm contains small cell cavities. It is filled with cell sap.
(v) Mesosomes : The plasma membrane folds inward to form a sac-like structure. It is called mesosome. Mesosomes are called chondroids. It helps in breathing. It carries out DNA replication and forms the cell wall during cell division. Gram positive bacteria have mesosomes.
(vi) Plasmid: Extra-chromosomal circular double-stranded DNA located in the cytoplasm of the cell is called plasmid. It is self-reproducing. It carries several types of genes. Fertility factor (F-factor), Resistance factor (R-factor), Nitrogen fixing genes (Nif-genes) etc. It acts as a carrier in genetic engineering.

The fine, living, thin and elastic membrane located inside the cell wall is called plasma membrane. It is composed of proteins and phospholipids. The plasma membrane contains sterols called hepanoids. It contains 70-80% protein and 20-30% lipid. It is 7.5-8.0 nm thick. It contains permease enzyme. This enzyme transports proteins.

The tough, firm, thick and elastic membrane inside the capsule layer of bacteria is called cell wall. It is inert in nature. It is composed of mucopeptide or peptidoglycan or murine. However, cell walls also contain proteins, lipids and polysaccharides. It contains some amount of muramic acid and teichoic acid. It is 10-50 millimicrons thick. The cell wall has several pores at places. Each pore is 1 millimicron in diameter. Exchange of essential substances takes place through these pores. It gives specific shape to cells and protects them from external injury.