When DNA is compacted by histones into 10 nm and 30 nm fibers, the DNA is unable to interact with proteins required for gene expression. Therefore, to allow for these proteins to act, the chromatin must constantly alter its structure. Which processes contribute to this dynamic activity?

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#Question id: 16477

#SCPH06 I Botany

Individual cell lineages are first isolated from an organ they are then grown separately to high density in a three- dimensional matrix. This  type of culture is called

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#Question id: 8698

#SCPH06 I Botany

Use the figure to answer the following question.

If the figure above is an accurate depiction of relatedness, then which of the following should be an accurate statement?

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#Question id: 16126

#SCPH06 I Botany

2 You are studying regulation of the yeast enzyme glutamine synthetase (GS), which is encoded by the GLN1 gene. You have isolated two mutants, designated gln2– and gln3–, that give decreased GS activity. Mating of either gln2– or gln3– haploids to wild type produces heterozygous diploids that show normal amounts of GS expression. When you cross either a gln2– or gln3– haploid to a gln1– strain the resulting diploids show normal expression of GS, that could explain the effect of the gln2– and gln3– mutations on the regulation of GLN1.

The GLN1 gene shows a rather complex regulation in response to different amino acids. When either glutamate (glu) or glutamine (gln) is added to the medium, the amount of GS expression diminished and when both glutamate and glutamine are added to the medium GS expression is shut off completely. The effects of different mutants on the response to glu and gln are shown below.

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#Question id: 13087

#SCPH05 I Biotechnology

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.

                              

Which of the following restriction enzyme is the best choice for you use to design a way to get the insert into the vector?

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#Question id: 8290

#SCPH06 I Botany

If, someday, an archaean cell is discovered whose rRNA sequence is more similar to that of humans than the sequence of mouse rRNA is to that of humans, the best explanation for this apparent discrepancy would be ________.