Protoplasm is the essence of life. We can refer to all the constituents of the cell collectively by the term Protoplasm. It shows all those activities that are characteristic of life.
A most common and important source of genetic variability is known to be present uniformly throughout the genome is termed Single Nucleotide Polymorphisms or SNPs. Interest in SNPs lies in the fact that these polymorphisms may be responsible for the differences in disease susceptibility, drug metabolism and response to environmental factors between individuals. Even, if they are not directly responsible for the disease, they serve as genetic markers for a nearby locus that might be responsible.
An average Human cell (diploid) contains about 6.4 billion base pairs of DNA divided among 46 chromosomes. The length of each base pair is about 0.34 nm. Therefore, if the DNA molecule in a diploid cell were laid out end to end, the total length of DNA would be approximately 2 meters.Since the diameter of a typical cell nucleus is only 10 μm, it is obvious for us to know that how is it possible to fit 2 meters of DNA in such small space without getting tangled up. The answer lies in the remarkable manner in which a DNA molecule is packaged.
We all know that DNA acts as a genetic material in most of the organisms on this planet earth. However, it is also clear that RNA also acts a genetic material, but only in some viruses. During the evolution, nature has considered DNA over RNA as genetic material, because DNA is more stable and more efficient than RNA.
Several Bacteria (like Escherichia Coli) exhibit a form of sexual reproduction called Bacterial Conjugation. It is the transfer of genetic material between bacterial cells by direct cell-to-cell contact or by a bridge-like connection between two cells.