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 mutation, designated MelB–, which gives uninducible melibiase activity. Mapping experiments show that MelB– is linked to Mel1. Using an F' factor that carries the chromosomal region surrounding Mel1, you perform the following genetic tests:

                      

Describe the basic genetic properties of the MelB– mutation?

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#Question id: 5053

#SCPH06 I Botany

Local cell signaling is carried out via membrane receptors that bind to proteins in the extracellular matrix (ECM) or directly to receptors from a neighboring cell in a process called as-

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#Question id: 10796

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

Flavonoids are one of the largest classes of plant phenolics, structure of flavonoids;

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#Question id: 1300

#SCPH06 I Botany

Which of these is NOT a component of plant cell walls?

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#Question id: 13091

#SCPH06 I Botany

To express a yeast gene in E. coli, your task is to design a strategy to insert the yeast gene into the bacterial plasmid. Below is a map of the area of the yeast genome surrounding the gene in which you are interested.

 

The distance between each tick mark placed on the line above is 100 bases in length

Below are the enzymes you can use, with their specific cut sites shown 5’-XXXXXX-3’ 3’-XXXXXX-5’

 

The plasmid is 5,000 bases long and the two farthest restriction enzyme sites are 200 bases apart. The plasmid has an ampicillin resistance gene somewhere on the plasmid distal from the restriction cut sites.

                              

You do the digestion of the insert and the vector and then ligate the two digestions together. You then transform the ligation into bacteria and select for ampicillin resistance. You get three colonies on your transformation plate. You isolate plasmid from each one and cut each plasmid with the enzyme XbaI. You then run your three digestions on an agarose gel and see the following patterns of bands. Describe what each plasmid actually was that was contained in each of the three colonies.

 

Which colony’s plasmid do you actually want to use for your studies?

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#Question id: 10337

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

In biological nitrogen fixation, the process of nitrification by organism respective bacteria A--which convert the ammonia to nitrite and B--- further converted into nitrate in the soil by their respective A and B bacteria known as;