Question

1.

Restriction enzymes (select all that apply):

Always produce sticky ends.

Typically cleave at palindromic sequences 4-8bp long.

Cleave invading viral DNAs.

Are found in a wide variety of mammalian cell types.

Are necessary for joining two DNA fragments together. 2. A polylinker is: A synthetic fragment that contains multiple sites for restriction enzymes to cut the DNA. A synthetic fragment inserted into a vector that allows replication of the vector in the host cell. An enzyme used to connect DNA fragments together. A synthetic fragment used in colony hybridization to visualize colonies that contain the DNA of interest. A sequence that allows for selection of cells that contain the vector. 3. A plasmid vector typically has which of the following features? Select all that apply. An origin of replication. Small size to facilitate entry into the cell and biochemical manipulation of the DNA. A selectable marker to ensure that the only cells containing the intact vector can grow. Unique restriction sites for insertion of DNA. 4. A DNA sequence of interest was digested and ligated into the middle of the AmpR gene region of pBR322 vector. The vector also contains a TetR gene which is not interrupted. After introducing the recombinat DNA into bacterial cells, the resulting transformants were tested on a variety of media. Which of the following results would be expected? Growth on tetracyclin containing media. Growth on media containing both tetracyclin and ampicillin. Death on media containing both tetracyclin and ampicillin. Growth on ampicillin containing media. 5. How are recombinat DNAs introduced into bacterial cells? Many bacterial cells can be transformed after being made competent by treatment with cold CaCl followed by a brief heat shock. Most bacterial cells are naturally competent so DNA just needs to be mixed with cells. Transformation can occur if DNA is mixed with bacterial cells that have already been heat shocked. Many bacterial cells can be transformed by applying high voltage to a mixture of cells and DNA for a sustained period of time. 6. Which of the following is true of genomic and cDNA libraries? Select all that apply. cDNA libraries contain sequences from expressed protein coding genes only. Genomic libraries usually contain large fragments and are likely to be constructed in YAC or BAC vectors. Genomic libraries contain fragments of genomic DNA that are generated by partial digests with restriction enzymes. cDNA libraries contain cDNAs made from all types of RNA. 7. Overexpression of proteins using bacterial vectors: always results in a properly folded, active protein. is so effective the expressed protein can represent as much as 80% of the total bacterial protein. makes subsequent purification of the recombinant DNA harder. requires eukaryotic ribosome binding sites to be present in the bacterial vector. requires a bacterial promoter to be present in the bacterial vector.

Answer 1

1.ResticRestriction enzymes:-

Typically cleave at palindromic sequences 4-8bp long.

Cleave invading viral DNAs.

2.A polylinker is:-A synthetic fragment that contains multiple sites for restriction enzymes to cut the DNA.

3.plasmid vector typically has following features:-An origin of replication.

A selectable marker to ensure that the only cells containing the intact vector can grow.

Unique restriction sites for insertion of DNA.

4.DNA sequence of interest was digested and ligated into the middle of the AmpR gene region of pBR322 vector. The vector also contains a TetR gene which is not interrupted. After introducing the recombinat DNA into bacterial cells, results would be Growth on tetracyclin containing media.Because In the trnasfomed bacteria, tetracycline resistance gene is intact so it grows on tetracycline media.

5.following is true of genomic and cDNA libraries:-cDNA libraries contain sequences from expressed protein coding genes only.

Genomic libraries usually contain large fragments and are likely to be constructed in YAC or BAC vectors.

Genomic libraries contain fragments of genomic DNA that are generated by partial digests with restriction enzymes.

Last option is incorrect because cDNA library made from only mRNA. Not from all types of RNA.

7.Overexpression of proteins using bacterial vectors:-Requires a bacterial promoter to be present in the bacterial vector.