BIOTECH EXAM 2 FULLY SOLVED TEST PAPER
GRADED A+
◉ What happens when Blue-white selection is interrupted by an
inserted gene.
Answer: the laxZ gene cannot produce functional Beta galactosidase.
◉ What is non-functional lacZ.
Answer: White colony. Clones. Genetically identical bacterial cells
each containing copies of recombinant plasmid.
◉ What happens when X-gal is added to media in petri plate?.
Answer: functional lacZ=blue colony=clones= genetically identical
bacterial cells each containing recircularized plasmid. no transgene.
◉ What was the first recombinant human protein marketed?.
Answer: Insulin, 1982
◉ What was the next human protein marketed?.
Answer: growth hormone, 1985
,◉ What was source of growth hormone prior to recombinant
technology?.
Answer: cadavers
◉ What makes a good vector in regards to size?.
Answer: small enough to be separated from chromosomal DNA of
host plasmid
◉ What makes a good vector in regards to origin of replication?.
Answer: site for DNA replication that allow plasmids to replicate
independently from host chromosome
◉ What is copy number?.
Answer: number of plasmids in the cell; normally small
(recombinant plasmids have high copy numbers)
◉ What makes a good vector in regards to Multiple cloning site?.
Answer: recognition sites for several restriction enzymes in which
DNA insert is cloned into
◉ What makes a good vector in regards to Selectable marker genes?.
Answer: allow to select for transformed colonies
,◉ What makes a good vector in regards to RNA polymerase
promoter sequences ?.
Answer: used for transcription in vitro and in vivo
◉ What prevents restriction enzymes produced by a bacteria from
digesting its own genome?.
Answer: Methylated DNA
◉ DNA Libraries.
Answer: Collections of cloned DNA fragments from a particular
organism contained in plasmid vectors within host
bacteria (ex. E. colt)
◉ What are the two types of libraries?.
Answer: Genomic DNA libraries and Complementary DNA libraries
(cDNA libraries)
◉ Genomic Libraries
What happens to Chromosomal DNA?.
Answer: isolated & digested with a restriction enzyme which
produces many fragments that include the entire genome
◉ Genomic Libraries
, What happens to the vector (plasmid)?.
Answer: digested with same enzyme
◉ Genomic Libraries
What happens to DNA ligase?.
Answer: used to ligate chromosomal DNA fragment within vector
DNA (plasmids)
◉ Genomic Libraries
What happens to recombinant vectors?.
Answer: used to transform
bacteria, and theoretically each bacteria will contain a single
recombinant plasmid
◉ What is the 1st disadvantage of genomic libraries?.
Answer: Introns are cloned in addition to exons. Majority of the
library will contain non-coding pieces of DNA.
◉ What is the 2nd disadvantage of genomic libraries?.
Answer: Many organisms have large genomes, searching for the gene
of interest is time consuming.
◉ What is the 3rd disadvantage of genomic libraries?.
GRADED A+
◉ What happens when Blue-white selection is interrupted by an
inserted gene.
Answer: the laxZ gene cannot produce functional Beta galactosidase.
◉ What is non-functional lacZ.
Answer: White colony. Clones. Genetically identical bacterial cells
each containing copies of recombinant plasmid.
◉ What happens when X-gal is added to media in petri plate?.
Answer: functional lacZ=blue colony=clones= genetically identical
bacterial cells each containing recircularized plasmid. no transgene.
◉ What was the first recombinant human protein marketed?.
Answer: Insulin, 1982
◉ What was the next human protein marketed?.
Answer: growth hormone, 1985
,◉ What was source of growth hormone prior to recombinant
technology?.
Answer: cadavers
◉ What makes a good vector in regards to size?.
Answer: small enough to be separated from chromosomal DNA of
host plasmid
◉ What makes a good vector in regards to origin of replication?.
Answer: site for DNA replication that allow plasmids to replicate
independently from host chromosome
◉ What is copy number?.
Answer: number of plasmids in the cell; normally small
(recombinant plasmids have high copy numbers)
◉ What makes a good vector in regards to Multiple cloning site?.
Answer: recognition sites for several restriction enzymes in which
DNA insert is cloned into
◉ What makes a good vector in regards to Selectable marker genes?.
Answer: allow to select for transformed colonies
,◉ What makes a good vector in regards to RNA polymerase
promoter sequences ?.
Answer: used for transcription in vitro and in vivo
◉ What prevents restriction enzymes produced by a bacteria from
digesting its own genome?.
Answer: Methylated DNA
◉ DNA Libraries.
Answer: Collections of cloned DNA fragments from a particular
organism contained in plasmid vectors within host
bacteria (ex. E. colt)
◉ What are the two types of libraries?.
Answer: Genomic DNA libraries and Complementary DNA libraries
(cDNA libraries)
◉ Genomic Libraries
What happens to Chromosomal DNA?.
Answer: isolated & digested with a restriction enzyme which
produces many fragments that include the entire genome
◉ Genomic Libraries
, What happens to the vector (plasmid)?.
Answer: digested with same enzyme
◉ Genomic Libraries
What happens to DNA ligase?.
Answer: used to ligate chromosomal DNA fragment within vector
DNA (plasmids)
◉ Genomic Libraries
What happens to recombinant vectors?.
Answer: used to transform
bacteria, and theoretically each bacteria will contain a single
recombinant plasmid
◉ What is the 1st disadvantage of genomic libraries?.
Answer: Introns are cloned in addition to exons. Majority of the
library will contain non-coding pieces of DNA.
◉ What is the 2nd disadvantage of genomic libraries?.
Answer: Many organisms have large genomes, searching for the gene
of interest is time consuming.
◉ What is the 3rd disadvantage of genomic libraries?.
