Salient features:
1. The members of this group are prokaryotes and lack motile reproductive structures.
2. The thallus is unicellular in Chroococcus, colonial in Gloeocapsa and filamentous trichome in Nostoc.
3. The protoplasm is differentiated into a centroplasm and a chromatophore bearing chromoplasm.
4. The photosynthetic pigments include c-phyocyanin and c-phycoerythrin along with myxoxanthin and myxoxanthophyll.
5. The reserve food material is Cyanophycean starch.
6. They reproduce only through vegetative methods and produce Akinetes, Hormogones, Endospores, Nanocysts.
7. Sexual reproduction is absent.

Asexual reproduction in Fungi:


1. Zoospores : They are flagellate structures produced in zoosporangia. Eg : Chytrids.
2. Conidia : The spores produced on conidiophores. Eg: Aspergillus.
3. Oldia/Thallospores : The hypha divide and develop in to spores called oidia. Eg : Erysiphe.
4. Fission : The vegetative cell divide into 2 daughter cells. Eg: Schizosaccharomyces- Yeast.
5. Budding: A small outgrowth is developed on parent cell, which gets detached and become independent. Eg :Saccharomyces - Yeast.
6. Chlamydospore: Thick walled resting spores are called chlamydospores Eg: Fusarium.

General characteristic features of Bacteria :
1. They are prokaryotic organisms and lack nuclear membrane and membrane bound organelles.
2. The genetic material is called nucleoid or genophore or incipient nucleus.
3. The cell wall is made up of polysaccharides and proteins.
4. Most of them lack chlorophyll, hence they are heterotrophic but some are autotrophic and possess Bacteriochlorophyll.
5. They reproduce vegetatively by fission and endospore formation.
6. They exhibit variations which are due to genetic recombination and is achieved through conjugation, transformation and transduction.
7. The shape and flagellation of the bacteria varies in different types of bacteria

1. In the lysogenic cycle the phage DNA gets integrated into the DNA of the host cell and gets multiplied along with nucleic acid of the host. No independent viral particle is formed.
2. As soon as the phage injects its linear DNA into the host cell it becomes circular and integrates into the bacterial chromosome by recombination. The integrated phage DNA is now called prophage.
3. The activity of the prophage gene is repressed by two repressor proteins which are synthesized by phage genes. This checks the synthesis of new phages within the host cell.
4. However, each time the bacterial cell divides, the prophage multiplies along with the bacterial chromosome.
5. On exposure to UV radiation and chemicals the excision of phage DNA may occur and results in lytic cycle.

Tobacco mosaic virus was discovered in 1892 by Dimitry Ivanowsky from Tobacco plant.
Structure of Tobacco mosaic virus:

1. TMV is a rod-shaped helical virus measuring about 280 x 150\(\mu\)m with a molecular weight of 39 x 10⁶ Daltons.
2. The virion is made up of two constituents, a protein coat called capsid and a core called nucleic acid.
3. The capsid is made up of approximately 2130 identical protein subunits called capsomeres.
4. The Nucleic acid consists of central single stranded RNA molecule.
5. The genetic information necessary for the formation of a complete TMV particle is contained in its RNA. It has 6,500 nucleotides.