The pathway for polypeptides exported from E. coli includes the following steps, which occur in what order for correct export?

1.  A chaperone, SecA, binds to the polypeptide.

2.  A chaperone, SecB, binds to the polypeptide.

3.  ATP is hydrolyzed by Sec A.

4.  SecA pushes 20 amino acids of the polypeptide into the translocation complex.

TLS Online TPP Program

#Question id: 15658

#SCPH01 Biochemistry

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.

Next, you isolate a third mutant, MelC–, which gives constitutive melibiase expression. The MelC– mutation is closely linked to Mel1 and MelB–. Genetic tests of the MelC– mutation yield the following:

 

As above, classify the MelC– mutation in terms of its basic genetic properties and explain how you arrived at your conclusions.

TLS Online TPP Program

#Question id: 7289

#SCPH28 | Zoology

The following scheme shows the flowering status of a plant species and the photoperiodism. Which of the following conclusions is most appropriate?

TLS Online TPP Program

#Question id: 11403

#SCPH06 I Botany

Several categories of risk of species extinction have been defined. A species can be determined as critical endangered if there is considered to be

TLS Online TPP Program

#Question id: 16318

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

Situational Stress:

TLS Online TPP Program

#Question id: 5260

#SCPH06 I Botany

Regarding prokaryotic reproduction, which statement is correct?