You are studying a new strain of E. coli that can utilize the disaccharide melibiose very efficiently. You find that utilization depends on the enzyme melibiase, which is encoded by the gene Mel1. Mel1 is not expressed unless melibiose is present in the growth medium.

You next construct a MelA– MelB– double mutant, which gives the following behavior:

 

Which of your two models is consistent with this new data?

a) the MelA- MelB- double mutant is identical to the MelB- mutant

b) MelA- is epistatic to MelB-

c) MelB- is epistatic to MelA-

d) the MelA- MelB- double mutant is identical to the MelA- mutant

Which of the following is the correct prediction about the double mutants?

TLS Online TPP Program

#Question id: 2074

#SCPH05 I Biotechnology

In some cells, there are many ion electrochemical gradients across the plasma membrane even though there are usually only one or two proton pumps present in the membrane. The gradients of the other ions are most likely accounted for by:

TLS Online TPP Program

#Question id: 1655

#SCPH01 Biochemistry

IgA in seromucus secretions:

TLS Online TPP Program

#Question id: 10358

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

Which of the following essential micronutrients is associated with nitrate reductase enzyme found in higher plants?

TLS Online TPP Program

#Question id: 11149

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

The Nernst equation specifies the equilibrium potential for a particular ion. This equilibrium potential is a function of ________.

TLS Online TPP Program

#Question id: 11424

#SCPH28 | Zoology

In robert h. Whittaker's approach to relating terrestrial biomes and climatic variables, the principal biomes fall in a triangular area that does not include climates with __________.