The effect of ultraviolet rays on the growth of P. fluoresce essays

The effect of ultraviolet rays on the growth of P. fluoresce essays Rapidly growing bacteria are exposed to constantly changing environments and must be able to adapt quickly if they are to survive and successfully compete with other organisms. Unless they take advantage of the change and respond quickly they will be crowded out by other organisms (Nester, 2004). There are many factors in the environment that are subject to change, for example availability of nutrients, water, oxygen, temperature and even effects of ultraviolet (UV) light. The modeling of the response of living organisms to a change in environment is an important issue of current interest. An example is the effect of ultraviolet radiation on biological systems (Delprato, 2001). UV rays are short waves of invisible light. A bacterium has three different mechanisms to adapt to their changing environment. One involves genetic modification or mutation. When an organism is exposed to UV radiation, covalent bonds between thymine molecules of the same DNA strand are formed called thymine dimers. The covalent bonding between these two molecules distort the DNA strand, damaging it in such a way that the DNA can neither be replicated nor transcribed at the site of mutation. Bacteria as well as other organisms are able to overcome this type of damage and repair themselves. An enzyme, in the presence of visible light, is used to break the covalent bonds. This process is called photoreactivation. Photoreactivation restores the bacterial DNA to its original state, thus allowing for replication and transcription. This process is thought to be important component of the bacterial arsenal in the repair or reversal of UV mediated DNA damage (Kim, 2001). Another mechanism to repair UV damage is called dark repair. It is called dark repair because it takes place in the absence of light. Dark repair involves another enzyme that excises the damaged segment from a strand of DNA and yet another enzyme repairs the resulting break by synth...