TLS Online TPP Program

#Question id: 15619


Wild type E. coli metabolizes the sugar lactose by expressing the enzyme ß-galactosidase. You have isolated a mutant that you call lac1–, which cannot synthesize ß-galactosidase and cannot grow on lactose (Lac–). During an condition isolate a mutation that constitutively expresses abnormally high levels of ßgalactosidase, which you designate lacc. Preliminary P1 transduction experiments indicate that lacc  is linked to the Tn5 insertion.  To map lacc  relative to lac1– you set up two reciprocal crosses. In the first cross you grow P1 on a strain that carries the Tn5 insertion and the lac1– mutation. You then use this lysate to infect a lacc mutant and select for Kanr. From 100 Kanr transductants examined, 20 are Lac–, 76 express ß-galactosidase constitutively and 4 show normal ß-galactosidase expression. In the second cross you grow P1 on a strain that carries the Tn5 insertion and the lacc mutation. You then use this lysate to infect a lac1– mutant, and select for Kanr. From 100 Kanr transductants examined, 81 are Lac– and 19  express ß-galactosidase constitutively. So what will be the correct order of  the Tn5 insertion and the lac1– and lacc  mutations. Express any measured distances as cotransduction frequencies.

#SCPH01 Biochemistry
  1. The correct order will be Tn5- lac1--lacc, Tn5 to lac1- distance is 24%  while Tn5 to lacc  distance is 18%.
  2. The correct order will be Tn5- lacc-lac1-, Tn5 to lac1- distance is 18%  while Tn5 to lacc  distance is 24%.
  3. The correct order will be lac1--Tn5-lacc, Tn5 to lac1- distance is 24%  while Tn5 to lacc  distance is 18%
  4.  The correct order will be Tn5- lac1--lacc, Tn5 to lac1- distance is 14%  while Tn5 to lacc  distance is 18%
More Questions
TLS Online TPP Program

#Question id: 10349

#SCPH05 I Biotechnology

Elevated plastid levels of glutamine stimulate the activity of glutamate synthase (also known as glutamine:2- oxoglutarate aminotransferase, or GOGAT). Given below some of the statements about GOGAT, which one of the following is incorrect?

TLS Online TPP Program

#Question id: 10349

#SCPH06 I Botany

Elevated plastid levels of glutamine stimulate the activity of glutamate synthase (also known as glutamine:2- oxoglutarate aminotransferase, or GOGAT). Given below some of the statements about GOGAT, which one of the following is incorrect?

TLS Online TPP Program

#Question id: 10350

#I Life Science/ Life Sciences Group – I-V

Ammonium can be assimilated via an alternative pathway rather than primary pathway which involves the sequential actions of glutamine synthetase(GS) and glutamate synthase(GOGAT), these alternative pathway catalyzes by enzyme known as,

TLS Online TPP Program

#Question id: 10350

#SCPH05 I Biotechnology

Ammonium can be assimilated via an alternative pathway rather than primary pathway which involves the sequential actions of glutamine synthetase(GS) and glutamate synthase(GOGAT), these alternative pathway catalyzes by enzyme known as,

TLS Online TPP Program

#Question id: 10350

#SCPH06 I Botany

Ammonium can be assimilated via an alternative pathway rather than primary pathway which involves the sequential actions of glutamine synthetase(GS) and glutamate synthase(GOGAT), these alternative pathway catalyzes by enzyme known as,

TLS Online TPP Program

#Question id: 10351

#SCPH06 I Botany

Plants contain two types of GOGAT; one accepts electrons from NADH, and the other accepts electrons from ferredoxin (Fd); which one of the following statements is correct?