MICROPROPAGATION

Generally plants propagate by sexual and asexual methods.Sexual method: here fertilization of ovary taken lace pollen grains and the resulting plants show high degree of heterogenecity.Asexual Methods: here the cells undergo mitosis and the resulting plants will be genetically identical to parents.Multiplication of genetically identical copies of plants is known as clonal propagation.Clonal propagation of plants through tissue culture is known as Micropropagation.Explants (starting material used to initiate tissue cultureThe explants widely used for tissue culture includea) Meristemb) Shoot-tipc) Auxiliary buds a) MeristemThis is the terminal portion of shoot tip containing a group of actively dividing cells.b) Shoot-tipShoot-tip/ shoot apex also contains a group of actively dividing cells...

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Posted in: Biotechnology

Chemical composition of eukaryotic chromosome

The eukayotic chromosome is composed of DNA, basic proteins called histones, non-histone proteins(involved in transcription, replication, repair and recombination of DNA) and RNA . The histone proteins are basic proteins rich in arginine and lysine. They are of 5 types-H1, H2A, H2B, H3 and H4.Eight molecules two each of H2A, H2B, H3 and H4. From an ellipsoid core (11nm long and 6.5-7nm in diameter) around which about 147-166bp of DNA coils in 13/4 turns. This DNA histone complex is called nucleosome, the building block of chromosome, the building block of chromosome found as repeating units. The nucleosomes appear as a string of beads in the chromatin. About 14-100bp of DNA between these beads forms the LINKER region.The hsitone H1 associates with the linker to aid folding of DNA into a more...

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Posted in: Microbiology

Chromosome of Cyanobacteria

The DNA in cyanobacteria is organized into a complex helical and folded structure and is distributed uniformly throughout the cytoplasm. It is likely that DNA is associated with histone like proteins and RNA. The size of the genome varies widely in cyanobacteria with molecular weight ranging between 1.6x109 and 8x109 daltons. Most of the unicellular cyanobacteria possess genomes of about 1.6x109 – 2.7x109 daltons. Filamentous cyano bacteria how ever have larger genomes.Viral GenomeThe core of the virion is made up of nucleic acid, either DNA or RNA never both. Four types of nucleic acid are formed in viruses with reference to number of strands. They formed in viruses with reference to number of strands. They are: 1- Single stranded DNA ( ssDNA) Eg.Ø X 1742- Double stranded DNA (dcDNA) Eg....

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Posted in: Microbiology

CHROMOSOME

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Posted in: Microbiology