Write short note on the following : Gene gun

Direct gene transfer methods are used to transfer the genetic material into a foreign organism especially a plant cell. Gene gun bombardment is a direct gene transfer method for the physical introduction of DNA into plant cells containing cell walls. DNA particles i.e., a gene of interest are coated with heavy metal i.e., tungsten or gold and fired using the micro-projectiles into cells using mechanical force.

Write differences between plasmid DNA and chromosomal DNA.

Feature Plasmid DNA Chromosomal DNA Properties Plasmid DNA is circular extra-chromosomal DNA, which is not associated with histone proteins. Chromosomal DNA is linear or circular double-stranded DNA associated with histone proteins. Feature Plasmid DNA Chromosomal DNA Occurrence This is present mostly in prokaryotic cells (bacteria) and in some species of single-celled eukaryotic fungi. This is present in both prokaryotic and eukaryotic cells.

Describe briefly about bioreactors.

The bioreactor is a closed system that supports the cultivation of organisms in order to form the desired product. This vessel carries out both aerobic and anaerobic processes. These are sterile cylindrical, stainless steel vessels (vary in sizes from litres to cubic metres) with temperature and pH controlling probes and gassing facilities required for the biochemical reaction. Large volumes of culture, i.e., 100 to 1000 litres of culture can be processed in bioreactors. Oxygen levels and the stirring rate are also monitored for maximised cell growth and productivity. The most common type of bioreactor is stirred tank bioreactor.