TLS Online TPP Program
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TLS Online TPP Program
#Question id: 12610
#Unit 10. Ecological Principles
If the Sun were to suddenly stop providing energy to Earth, most ecosystems would vanish. Which of the following ecosystems would likely survive the longest after this hypothetical disaster?
TLS Online TPP Program
#Question id: 16128
#Unit 13. Methods in Biology
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.
Next, you decide to evaluate the promoter for the GLN1 gene. To do this you first fuse the promoter region to the LacZ coding sequence and then place this hybrid gene on an appropriate yeast plasmid. You find that cells carrying the hybrid gene express activity under the same conditions that GS is expressed in wild type cells, meaning that the promoter region you have selected contains all of the necessary cis-acting sequences for normal regulation. The figure below shows the effect of different 50 bp deletions in the promoter region on the amount of ß-galactosidase activity expressed by the reporter gene. how would you expect a gln2– gln3– double mutant to behave?
TLS Online TPP Program
#Question id: 19110
#Unit 8. Inheritance Biology
If the frequency of PKU among newborns is approximately 1/10,000 (when the parents are unrelated). What is the risk of a child with PKU if the parents are siblings?
TLS Online TPP Program
#Question id: 4813
#Unit 8. Inheritance Biology
You perform the three different two-factor crosses (Cross 1: XY and xy, Cross 2: YZ and yz, and Cross 3: XZ and xz). Assume all crosses are between diploid flies homozygous for the alleles of these genes. You observe 7% recombinants in the first cross, 20% recombinants in the second cross, and 13% recombinants in the third cross. if cross between XyZ and xYz leads to which of the followining recombinant with double cross over .
TLS Online TPP Program
#Question id: 13090
#Unit 13. Methods in Biology
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.
What is the Colony 3’s plasmid is;