In a microtubule,

The end with exposed β-subunits is the (+) end

The end with exposed α-subunits is the (−) end

 

TLS Online TPP Program

#Id: 2733

#Unit 12. Applied Biology

For the generation of transgenic plant in crop improvement, one important regulatory gene ‘X’ was overexpressed in a crop plant. Out of 30 transgenic rice plants generated, 22 showed high levels of gene ‘X’ expression. However, rest 8 lines displayed low level of expression. One explanation of such observation may be: 

Suppression effect of the transgene 

Knock down effect of gene X 

Gene silencing effect 

Co-suppression effect of transgene

 

TLS Online TPP Program

#Id: 2734

#Unit 12. Applied Biology

Cultivation of transgenic plants for the recovery of pharmaceutical compounds (medicines) is popularly known as 'pharming';

TLS Online TPP Program

#Id: 6162

#Unit 12. Applied Biology

TLS Online TPP Program

#Id: 6163

#Unit 12. Applied Biology

Insect-resistant transgenic crops were first commercialized in the mid-1990s with the introduction of GM corn (maize), potato and cotton plants expressing genes encoding the entomocidal δ-endotoxin from Bacillus thuringiensis.

TLS Online TPP Program

#Id: 6164

#Unit 12. Applied Biology

The first commercial Bt cotton variety was released in USA by Monsanto (Bollgard), which contains Cry 1Ac gene of Bacillus thuringiensis. (first generation Bt-cotton)

TLS Online TPP Program

#Id: 6165

#Unit 12. Applied Biology

Second generation of improved Bt-cotton with two Bt-genes, now designated Bollgard II.  Bollgard II cotton contains Cry 1 A(c) and Cry II A(b).