Microbiology Final: Chapter 9

arrange the following in the proper sequence in which they occur during a single PCR cycle: 1. addition of DNA nucleotides by TaqDNA polymerase 2. complementary base pairing between primers and target DNA 3. heat separation

3-2-1

place steps in polymerase chain reaction cycle in order: 1. the products of one 3-step PCR cycle 2. cooling to 50 degrees celcius allows the added primers to anneal to the single stranded DNA 3. DNA synthesis occurs when the temperature is raised to 72 degrees celcius 4. heating to 95 degrees celcius denatures DNA

4-2-3-1

human DNA cut with restriction enzyme A can be joined to: A. bacterial DNA cut with restriction enzyme A B. human DNA cut with restriction enzyme B C. human DNA that is uncut D. bacterial DNA that is uncut

A

when cloning eukaryotic genes into bacteria for protein production, a copy of DNA that lacks introns must first be obtained. introns are removed from primary RNA transcripts by the cell's own machinery, but the copy of the DNA lacking introns must be generated by a biotechnology method. this intron-free copy of DNA is generated by: A. obtaining mRNA from the cell, then using reverse transcriptase enzyme to convert it into a cDNA molecule for insertion into the bacterial cell B. harvesting all DNA from the cell, then separating it on an agarose gel and taking the smallest fragments C. adding intronase to the eukaryotic cell DNA to digest all introns prior to cloning the remaining DNA into the bacterial cells D. obtaining mRNA from the cell instead to place into the bacterial cell's genetic information

A

you are trying to create a DNA library. you use restriction EcoR1 to digest both the DNA from your organism of interest, and also your vector, which in this case is plasmid Puc19. Puc19 has both a lacZ gene and ampicillin-resistance gene. you use DNA ligase to insert and seal the DNA fragments you have created into the vector. you then transform the e. coli with the recombinant DNA and plate the bacteria onto a nutrient medium containing substrate for the lacZ gene product. after incubation, you find that all of the colonies are white and do not contain any plasmid. which two of the following statements might explain your results: A. you forgot to put ampicillin in the medium B. you forgot to put x-gal in the medium C. the DNA polymerase you used did not function D. the e. coli was not competent E. you forgot to put lacZ in the medium F. the DNA ligase you used did not function

A and D

if you did a cloning experiment but you accidentally left x-gal out of the medium you use to grow your transformants, what would be the result (assuming you remembered all other important ingredients in your culture medium, including ampicillin)? A. all cells that grow would produce blue colonies B. all cells that grow would produce white colonies C. cells that grow would produce white or blue colonies D. no cells would grow

B

please choose the statement that describes the purpose of DNA microarray analysis: A. used to separate DNA fragments based on size B. used to determine which genes are being transcribed C. used to amplify sequences of DNA D. used to prepare a DNA profile

B

during PCR, which primer anneals to DNA with its 3 end? A. reverse primer only B. neither forward nor reverse primer C. both forward and reverse primer D. either forward or reverse primer, but not both

C

in order for insertional inactivation of a gene to occur, the restriction site must be: A. at the end of the gene B. at the beginning of the gene C. in the middle of the gene D. does not matter where the site is

C

please choose the statement that best describes the role of restriction enzymes in genetic engineering: A. used to replicate specific sequences of DNA B. used to join different segments of DNA C. used to cut DNA at specific locations D. used to sequence long stretches of DNA

C

which of the following can serve as selective markers for identifying recombinant bacterial cells A. antibiotic resistance B. differences in colony phentypes C. all of the above

C

place the steps involved in creating a DNA library into the correct sequence. A. bacteria such as e. coli are made to take up the recombinant DNA (vector with insert) B. bacteria containing vector with inserted DNA are selected on appropriate medium C. DNA is extracted from the organism of interest D. DNA is digested using restriction enzyme E. the vector is sealed with DNA ligase F. restriction fragments are inserted into a vector

C-1 D-2 F-3 E-4 A-5 B-6

plasmids are made of

DNA

T/F: an endonuclease will cut DNA only at the ends of the molecule

F

T/F: bioengineered hormones, enzymes, and vaccines are easier to produce but not as safe as their natural equivalents

F

T/F: pathogenicity is a desirable feature of a cloning host

F

T/F: restriction enzymes are naturally found in eukaryotic cells

F

T/F: when foreign DNA and plasmid are both cut with the same restriction enzyme and mixed together, all molecules will form recombinants

F

T/F: DNA microarrays may be used to study how a cell responds to specific environmental conditions

T

T/F: genetic engineering involves the intentional manipulation of an organism's genetic material

T

T/F: if host cells are ampicillin-sensitive and are plated on a medium containing ampicillin, only cells that have taken up the ampicillin-resistant vector can grow

T

T/F: plasmids are naturally found in some bacteria

T

T/F: the primary purpose of recombinant DNA technology is to deliberately remove genetic material from one organism and combine it with that of a different organism

T

a specimen from a vaginal sample is subjected to polymerase chain reaction. primers specific for a gene in the bacterium n. gonorrhoeae are used in the reaction, and an amplified DNA product is visualized on an agarose gel. this can lead a physician to conclude that: A. the patient is not infected B. the patient is infected C. the patient is producing antibodies against the bacteria D. the test is not sensitive enough to assess whether the patient is infected or not

B

cDNA used in microarrays is synthesized using the enzyme: A. DNA polymerase B. reverse transcriptase C. RNA polymerase D. DNA ligase

B

why is a selective marker, such as drug resistance, important in recombinant DNA technology?

it makes it possible to easily identify recombinant cells