Exam 18: Recombinant Dna and Biotechnology

The plant disease called crown gall is caused by the

Refer to the figure showing the steps used in microarray analysis to detect differences in expression between tumor tissue and normal tissue.The spots in the bottom panel represent individual genes for patients who have good prognoses (left) as well as for patients who have poor ones (right).The colors of those spots represent levels of expression: red = high expression, yellow = intermediate expression, green = low expression. Look at the lowest, right-most gene in both patterns.Does expression of this gene correlate with the prognoses? Explain your answer.

A biologist used microarrays to examine how gene expression in a fish changes with temperature.Refer to the table showing the expression levels of four (of several thousand) genes at varying temperatures.Values for expression have been normalized such that the expression at 15°C for any particular gene is always 100. The expression of gene(s) _______ steadily decline(s) as temperature increases.

The production of a strain of corn that is genetically engineered to tolerate low pH and therefore thrive in a field exposed to acid rain is an illustration of

Which statement about selectable marker genes and reporter genes is true?

_______ would be added to an expression vector if the researchers wanted to direct the gene product to the nucleus after its production.

Refer to the figure showing the steps used in microarray analysis to detect differences in expression between tumor tissue and normal tissue.The spots in the bottom panel represent individual genes for patients who have good prognoses (left) as well as for those who have poor ones (right).The colors of those spots represent levels of expression: red = high expression, yellow = intermediate expression, green = low expression. At what stage does hybridization with oligonucleotides occur?

Biologists examining the plant gene LEAFY's effect on expression patterns of genes overexpressed and underexpressed LEAFY.They then performed microarray analysis to examine the effects of changes of LEAFY expression on the expression of other genes in the genome.Refer to the table showing the results for four different genes with LEAFY underexpressed and overexpressed and the control.The expression levels are normalized such that they are 100 for each gene in control conditions. Which pattern is exhibited by gene 762?

Which is a difference between PCR and DNA replication in the cell?

Suppose one restriction enzyme (enzyme A) makes two cuts in a circular DNA molecule, and another restriction enzyme (enzyme B) makes one cut in that same DNA.The cuts are not in the same place, and the cut fragments are not exactly the same size.The restriction digestion is set up on an electrophoresis gel.How many bands should the gel pick up if only enzyme A is used in the restriction digestion?

You are interested in determining which genes are being expressed at a particular apical meristem of a plant at a particular time.For this, you will most likely use

Suppose a DNA fragment from a human gene has been cut such that it has sticky ends.A DNA fragment from bacteria with sticky ends complementary to those of the human DNA is added to the mix.What would prevent the complementary ends of the human DNA from rejoining, and thus encourage the formation of a recombinant DNA molecule?

A human transgene is carried into a yeast host cell via a virus.Here the virus is serving as a(n)

A bacteriophage library of the horse genome would have _______ volumes than the comparable plasmid library, because phage libraries _______.

Recombinant DNA technology requires not only getting the DNA into the cell, but also getting it to replicate appropriately.In this process, the specificity of which enzyme can present a challenge?

Which statement best describes the major advantage of using microarrays rather than RT-PCR to detect gene expression differences across the genome?

The process of inserting recombinant DNA is considered transfection when

Different genetic variants at a locus affect timing of reproduction in houseflies.There is some evidence that this locus affects the reproductive patterns by altering the expression of other loci.To investigate this further, biologists can use _______ to alter the sequence of the gene and microarrays to investigate the genome-wide patterns of gene expression caused by such alterations.

Which entity or molecule can convert the artificial substrate X-Gal into a blue product?

A biologist expressing a plant transgene in bacterial cells is able to turn on and off the transgene's expression at will.Most likely the biologist has incorporated a(n) _______ in the expression vector.