SOS response in E. coli:

When DNA is extensively damaged (such as by UV light), DNA replication is halted and the number of single-strand gaps in the DNA increases.

RecA protein binds to this damaged, single-stranded DNA, activating the protein’s co-protease activity.

While bound to DNA, the RecA protein facilitates cleavage and inactivation of the LexA repressor. When the repressor is inactivated, the SOS genes, including RecA, are induced;

TLS Online TPP Program

#Id: 7320

#Unit 12. Applied Biology

Phytoremediation is the use of green plants and their associated microorganisms, soil ammendments, and agronomic practices to remove, harmfull environmental contaminants.

TLS Online TPP Program

#Id: 7321

#Unit 12. Applied Biology

Phytovolatilization

Plants remove inorganic contaminants· either by contaminant volatilization or by metal accumulation.

Volatalization is useful for the removal of mercury. A bacterial mercuric ion reductase has been transferred to Arabidopsis thaliana; this transgenic plant absorbs mercury, and reduces it to volatile Hg0, which volatilizes from the leaf surface.

TLS Online TPP Program

#Id: 7322

#Unit 12. Applied Biology

Rhizofiltration is a process that filters water through a mass of roots to remove toxic substances or excess nutrients. The pollutants remain absorbed in or adsorbed on to the roots. As the roots become saturated with contaminants, they are harvested and disposed. 

TLS Online TPP Program

#Id: 7323

#Unit 12. Applied Biology

Phytodegradation works best with organic contaminants like herbicides, trichloroethylene, and methyl tert-butyl ether (MTBE – a volatile substance). 

TLS Online TPP Program

#Id: 860

#Unit 13. Methods in Biology

The PCR consists of three defined sets of times and temperatures, termed steps

a) Denaturation at 94°C, for 0.5 min

b) Primer annealing at 55°C for 1.5 min

c) Extension at 72°C for 1 min

TLS Online TPP Program

#Id: 861

#Unit 13. Methods in Biology

The time taken for each cycle is considerably longer than 3 min (0.5 + 1.5 +1 min)