Helix-turn-Helix

Two helices are connected by a small loop or turn

These helices are stabilized by non-polar contacts between the helices

Mostly found in DNA binding proteins, directly involved in DNA binding

Generally consists of 20 amino acids

Second helix is involved in DNA binding, enters in major groove of the target site

TLS Online TPP Program

#Id: 6226

#Unit 12. Applied Biology

The genomes of all retroviruses contain the three genes gag, pol and env.

For sustainable expression of a trangene in the successive generation of a cell line in culture, the ideal gene transfer can be obtained using 

 lentiviral vector 

adenoviral vector 

 plasmid DNA containing the transgene 

only transgenic DNA

TLS Online TPP Program

#Id: 7305

#Unit 12. Applied Biology

Use of biological organisms, such as, bacteria, fungi (usually), and plants to reduce or eliminate toxic pollutants from contaminated sites by degradation or assimilation in the atmosphere is called bioremediation. 

TLS Online TPP Program

#Id: 7306

#Unit 12. Applied Biology

Microbial leaching of copper with the common copper ore CuS, in which copper exists as Cu2+   Acidophillus ferrooxidans oxidizes the sulfide in CuS to SO42, releasing Cu2+.

TLS Online TPP Program

#Id: 7307

#Unit 12. Applied Biology

TLS Online TPP Program

#Id: 7308

#Unit 12. Applied Biology

In uranium leaching, Acidophillus ferrooxidans oxidizes U4+ to U6+ with O2 as an electron acceptor. 

However, Uranium leaching depends more on the abiotic oxidation of U4+  by Fe3+ with A. ferrooxidans contributing to the process mainly through the reoxidation of Fe2+ to Fe+3, as in copper leaching.

TLS Online TPP Program

#Id: 7309

#Unit 12. Applied Biology

The major form of Hg in the atmosphere is elemental mercury (Hg0 ), which is volatile and is oxidized to mercuric ion (Hg2+) photochemically. Most mercury thus enters aquatic environments as Hg2+.