PCB 3063 Lecture Notes - Lecture 49: Yeast Artificial Chromosome, Multiple Cloning Site, Lambda Phage

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3 Apr 2018

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Dna (can carry up to 45 kb of cloned dna) bacterial artificial chromosomes (bacs) and yeast artificial chromosomes (yacs) 2 other examples of vectors that can be used to clone large fragments of dna polymerase chain reaction (pcr) see fig. Info about nucleotide sequence of target dna must be known to synthesize primers. Cannot amplify long segments of dna (several thousand nucleotides in length) semiconservative model of dna replication each replicated dna molecule consists of one old and one new dna strand. Grew e. coli in 15nh4cl (denser isotope of n) Sedimentation equilibrium centrifugation (sec): samples are forced by centrifugation through a density gradient of a heavy metal salt; molecules of dna reach equilibrium when their density equals the density of the gradient medium. 15n cells were transferred to a medium containing only 14nh4cl. E. coli replicated over several generations and samples were taken from each; dna isolated from ea. sample and subjected to sec.

Related Questions

1. You have cloned a human gene along with its promoter and ribosome-binding site in a bacterial cloning vector and then introduced the recombinant plasmid into a bacterial host cell that supports the replication and segregation of the cloning vector. Unfortunately, even though you know the whole human gene sequence is present (by DNA hybridization); you cannot get expression of the gene. Which of the following is NOT a reason why there is no expression?

A. The vector cannot replicate

B. The human promoter is not recognized by the bacterial host cell

C. The ribosome-binding site is not recognized by the bacterial host cell

D. The human gene lacks introns, so it is not transcribed by the host bacterium

2. Restriction endonucleases are:

A. sequence-specific

B. able to recognize any 4-, 6-, or 8-base pair sequence

C. always able to produce single stranded tails

D. only able to cleave bacterial DNA

3. Which of the following is NOT a required characteristic of cloning vectors?

A. Genes for replication of vector DNA and segregation to progeny cells

B. Genes for selection of cells carrying the vector (e.g., antibiotic-resistance)

C. DNA sequence for the introduction of foreign DNA where the integrated DNA does not disable the vector

D. None of the above

4. A poly (T) primer is used to produce cDNA from mammalian mRNA. Which of the following would be used to produce cDNA from bacterial mRNA?

A. A poly (T) primer

B. A random DNA sequence primer

C. A poly (A) primer

D. A poly (GC) primer

Please answer the following multiple-part question regarding vectored cloning:

a) A cloning vector must _________.

A. be a circular dsDNA molecule

B. contain a replication origin

C. contain an multicloning site (MCS)

D. contain marker genes

b) Vectored cloning is superior to PCR cloning of a gene in terms of __________.

A. time it takes to finish cloning

B. size of DNA that can be cloned

C. amounts of cloned DNA that can be generated

D. ease of isolation of the DNA fragment to be cloned

c) Which of the following is a recombinant DNA molecule?

A. pUC DNA digested by EcoRI

B. Fish insulin gene, PCR amplified and then cut by EcoRI

C. pUC18 DNA and fish insulin DNA ligated by a DNA liagse

D. pUC DNA and fish insulin gene DNA, both cut by EcoRI and mixed

d) You may insert a foreign DNA fragment inside a live cell using each of the following methods except________.

A. inject the DNA inside the cell

B. mix the DNA with the cell and freeze the mixture in liquid nitrogen

C. mix DNA with the cell and momentarily heat the cell then cool down

D. mix DNA with the cell and momentarily zap the cells with a high voltage

E. cover the DNA in a lipid micelle and mix the micelle with the cell

e) Technically, the ampicillin resistance gene is a selectable marker gene but the beta lacZ gene or the green fluorescent protein (GFP) gene is a reporter gene of a cloning vector. What is the difference between a selectable marker and a reporter gene?

A. A selectable marker is a bacterial gene, a reporter gene is a eukaryotic gene

B. Marker genes are used in bacterial system; reporter genes are used in eukaryotic system.

C. The selectable markers help eliminate cells lacking the maker, reporter genes do not offer this option.

View/perform/read ALL THREE of the following prior to answeringthe questions.

http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/120078/micro10.swf::Stepsin Cloning a Gene (Links to an external site.)

http://www.discoverbiotech.com/wiki/-/wiki/Main/Applications ofCloning (Links to an external site.)

http://www.wiley.com/college/boyer/0470003790/animations/cloning/cloning.htm(Links to an external site.)

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From the list below, which of the following is the most logicalsequence of steps for splicing foreign DNA into a plasmid andinserting the plasmid into a bacterium?
I. Transformbacteria with recombinant DNA molecule
II. Cutthe plasmid DNA using restriction enzymes
III. Extractplasmid DNA from bacterial cells
IV. Hydrogen-bondthe plasmid DNA to nonplasmid DNA fragments
V. Useligase to seal plasmid DNA to nonplasmid DNA

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Plasmids (or vectors) are important in biotechnology becausethey are

a vehicle for the insertion of recombinant DNA intobacteria.

surfaces for respiratory processes in bacteria.

recognition sites on recombinant DNA strands.

surfaces for protein synthesis in eukaryotic recombinants.

proviruses incorporated into the host DNA

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Plasmids are put into bacterial cells by

restriction enzymes

DNA ligase

binding of cohesive sticky ends

transformation

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Restriction enzymes usually

cut donor DNA evenly so smooth edges result

cut donor DNA but do not affect plasmids

make staggered cuts at specific sequences in DNA in both donorDNA and plasmid

are used in ligating plasmids into bacterial host cells

more than one of the above

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After combining DNA fragments in a cloning experiment, ___ isused to covalently join the DNA segments.

Restriction enzyme

DNA Ligase

Reverse transcriptase

DNA polymerase

Helicase

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It is theoretically possible for a gene from any organism tofunction in any other organism. Why is this possible?

All organisms have ribosomes.

All organisms have the same genetic code.

All organisms are made up of cells.

All organisms have similar nuclei.

All organisms have transfer RNA.

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Assume that you are trying to insert a gene into a plasmid andsomeone gives you a DNA sample cut with restriction enzyme X. Thegene you wish to insert from the given sample has sites on bothends for cutting by restriction enzyme Y. You have a plasmid with asingle site for Y, but not for X. Your strategy should be to

cut the plasmid with restriction enzyme X and insert thefragments cut with Y into the plasmid.

cut the plasmid with enzyme X and then insert the gene into theplasmid.

cut the DNA again with restriction enzyme Y and insert thesefragments into the plasmid cut with the same enzyme.

cut the plasmid twice with restriction enzyme Y and ligate thetwo fragments onto the ends of the human DNA fragments cut withrestriction enzyme X.

insert the fragments cut with X directly into the plasmidwithout cutting the plasmid.

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Which of the following is/are false in regard to expressionplasmids (also called expression vectors)?

They are used to make proteins using a cloned gene.

They contain a promotor.

They are the first plasmid type used to clone a gene.

They contain a terminator.

More than one of the above is false.

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What is NOT a potential problem(s) associated with usingbacteria containing a cloned eukaryotic gene (e.g. a human gene) toproduce a functional protein?

If the eukaryotic gene contains introns the bacteria will notremove them and the resulting amino acid sequence will be differentthat that made by a eukaryote.

The bacteria may not fold the protein correctly.

The bacteria may degrade the protein.

All of the above are potential problems.

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Cloning allows for production of proteins in much larger amountsthan occurs in the cells from which the gene is isolated.

True

False

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Question 111 pts

Gene cloning is used to do all of the following except

Make insulin