Pick the correcty answer If a mutation that inactivated telomerase occurred in a cell(telomerase activity in the cell = zero), what do you expect theoutcome to be?

The position of the centromere would shift at each replicationcycle, eventually leading to mutations in the genetic informationand cell death. The number of tandem repeats would increase with eachreplication cycle, eventually leading to a large unstablechromosome and cell death. The telomeres would shorten at each replication cycle,eventually leading to loss of essential genetic information andcell death. DNA primase would be unable to bind to the 5 end of thetemplate strand, eventually causing a reduction in chromosome sizeand cell death.

	Somatic or body cells have very little telomerase. As a result,the telomeres within these (proliferating) cells _____ with eachcell division.
	shorten lengthen remain constant in size can either shorten or lengthen None of the answers is correct.

A researcher is studying telomerase in four types of mousecells: brain cells, skin cells, blood cells, and gametes(sperm/eggs). What do you suspect she will find?

telomerase activity/amount will be highest in skin cells telomerase activity/amount will be highest in brain cells telomerase activity/amount will be highest in blood cells telomerase activity/amount will be highest in gametes(sperm/eggs) telomerase activity/amount will be the same in all of the celltypes Examples of hybridization of single-stranded DNAs used inChapter 10 include: primers used in DNA sequencing and in PCR sticky-end cloning probes used in Southern and Northern blotting and in diagnosisof mutations All of the answer options are correct. Examples of proteins that bind to DNA and then act on it, foundin Chapter 10, include: restriction enzymes Taq DNA polymerase DNA ligase All of the answer options are correct. Why is ligase needed to make recombinant DNA? It enables the donor fragments and the vector DNA molecules toinitially hybridize. It is responsible for forming the complementary sticky ends ofthe donor fragments and the vector DNA. It is only used when blunt-ended vectors are used to formrecombinant plasmids. It creates phosphodiester bonds at the sites where inserted DNAand vector have attached by complementary base pairing. It is used in the isolation of recombinant plasmids from thoseplasmid vectors that did not take up donor DNA. What would be the immediate consequence in the cloning processif someone forgot to add ligase? There would be no hybridization between the vectors and thedonor DNA fragments. No complementary sticky ends would form in either the vectorsor the donor DNA molecules. Blunt-ended vectors would be able to form covalent bonds withdonor DNA. The inserted DNA and the vector would be held together only byhydrogen bonds, so recombinant plasmids would lose the insertedDNA. Recombinant plasmids could not be separated from nonrecombinantplasmids. In the PCR process, if we assume that each cycle takes fiveminutes, how many-fold amplifications would be accomplished in onehour? 12-fold 32-fold 512-fold 4096-fold The position of the gene for the protein actin in the haploidfungus Neurospora is known from the complete genomesequence. If you had a slow-growing strain that you suspected ofbeing an actin mutant and you wanted to verify that it was one,would you (1) clone the mutant by using convenient restrictionsites flanking the actin gene and then sequence it, or (2) amplifythe mutant sequence by using PCR and then sequence it? The better choice is to clone and sequence the actin gene toconfirm that it has mutated. This is a dependable method providedthat suitable restriction sites are available. The better choice is to amplify the actin gene sequence fromthe mutant and sequence it to confirm that it has mutated. PCRrequires fewer steps, and it can be completed more quickly.However, it requires the production of suitable primers. Why is it necessary to use a special DNA polymerase(Taq polymerase) in PCR? because the reaction starts with very small amounts of DNAtemplate because the polymerase has to be able to remain active afterheating to 95 degrees Celsius because the reaction uses primers which are not usuallyrequired for DNA replication because the amount of template increases with each cycle One feature that virtually all plasmid vectors have in common isthe polylinker (also called a multiple cloning site). This isimportant because it helps select transformants from nontransformants. it carries convenient restriction enzyme sites into which theDNA to be cloned may be inserted. it allows the vector to replicate independent of host. All of the answer options are correct. Virtually all plasmid vectors have a selectable marker. This isimportant because it helps select transformants from nontransformants. it carries convenient restriction enzyme sites into which theDNA to be cloned may be inserted. it allows the vector to replicate independent of host. All of the answer options are correct. Prototrophy is often the phenotype selected to detecttransformants. Prototrophic cells are used for donor DNAextraction; then this DNA is cloned and the clones are added to anauxotrophic recipient culture. Successful transformants areidentified by plating the recipient culture on minimal medium andlooking for colonies. What experimental design would you use tomake sure that a colony that you hope is a transformant is not, infact, a revertant (mutation back to prototrophy by a secondmutation in the originally mutated gene) of the auxotrophicmutation? Use an auxotroph that cannot revert as the recipient, such asone that contains a deletion. Include a selectable marker on the vector that is added to theauxotrophic recipients. Then use the selection conditions toconfirm that the colony is a transformant. Sequence the gene of interest isolated from a putativetransformant to determine if additional mutations haveoccurred. All of the answer options are correct.