Exam 17: Recombinant Dna Technology

Which term refers to the process in which DNA can be introduced into host bacterial cells?

Molecular biologists rely on many, often sophisticated, techniques to pursue their discipline. Ultracentrifugation, electron microscopy, X -ray diffraction, electrophoresis, and computer interfacing are fundamental tools. Model organisms provide the raw materials for study. List three organisms (or organismic groups) often used by recombinant DNA technologists and describe a major advantage of each group.

In recombinant DNA technology, a YAC is an enzyme isolated from a large South American, four -legged mammal.

In the context of recombinant DNA technology, what is meant by the term vector?

To isolate a bacterium with a plasmid that carries a desired DNA fragment cloned within the ampicillin resistance gene, we should grow bacteria in a medium that contains ampicillin.

Assume that a researcher conducted a cloning experiment using a typical plasmid, transformed an appropriate host bacterial strain, and plated the bacteria on an appropriate X -gal medium. Blue and white colonies appeared. Which of the two types of colonies, blue or white, would more likely contain the recombinant plasmid? Why?

In a PCR, primers are complementary to stretches of DNA with which they anneal.

What is a cDNA molecule?

In what way are specific DNA sequences of the template amplified in the polymerase chain reaction? In other words, how does one target the target?

Some restriction endonucleases are capable of producing blunt ends; others can generate "sticky" ends.

Restriction endonucleases are especially useful if they generate "sticky" ends. What makes an end sticky?

Some restriction enzymes cleave DNA in such a manner as to produce blunt ends. Ligation of blunt end fragments is most often enhanced by the use of the enzyme terminal deoxynucleotidyl transferase. Speculate on the function of deoxynucleotidyl transferase in terms of using blunt end fragments in cloning.

Following are four processes common to most cloning experiments: transforming bacteria plating bacteria on selective medium cutting DNA with restriction endonucleases ligating DNA fragments Place these components in the order in which they would most likely occur during a cloning experiment.

Words such as did, mom, and pop have something in common with the fundamental tool of recombinant DNA technology. In the context of recombinant DNA technology, which term would be used to describe such words?

Vectors such as pUC18 and others of the pUC series contain a large number of restriction enzyme sites clustered in one region. Which term describes this advantageous arrangement of restriction sites?

Over the years, sophisticated plasmid vectors have been developed for use in recombinant DNA technology. List at least two features that have been introduced in particularly useful vectors.

If a researcher wishes to clone a gene using typical restriction endonucleases, how does the restriction endonuclease recognize genes in the genome?

Nucleic acid blotting is commonly used in molecular biology. Two types, Southern blots and Northern blots, involve gel electrophoresis and a filter, which holds the nucleic acid. Briefly describe the procedure of "blotting" in this context and differentiate between Southern and Northern blots.

E. coli is a common YAC.

Assume that a given plasmid vector to be used in a cloning experiment contains 4000 base pairs of DNA. Assume also that the restriction endonuclease Cuj cuts this plasmid at the following sites (starting from an arbitrary zero point): 1000, 1500, and 3000. Given complete digestion of the plasmid with the endonuclease so that only linear fragments are produced, what sizes of DNA are expected?