Chapter 20 Flashcards
What is recombinant DNA?
It refers to the joining of DNA molecules.
What is order of recombinant DNA?
cutting DNA with restriction enzymes
ligate into a vector
transfer into a host cell
let the host replicate the DNA
and recovering the DNA from the host cell.
What does a restriction enzyme do?
It cuts DNA at specific sequences.
It binds to DNA at a specific sequence and breaks the phosphodiester bonds.
Restriction enzymes cleaves these sequences can creates what kind of ends.
Cohesive Ends or Blunt Ends.
What does DNA ligase do?
It joins restriction fragments covalently to produce intact DNA molecules.
What are vectors?
DNA molecules that can replicate cloned DNA fragments in a host cell.
They also have several restriction enzymes that allow insertion of DNA along with a selectable marker such as antibiotic resistance.
What is a plasmid?
An extrachromosal double stranded DNA molecule that replicates autonmously in bacterial cells.
For DNA cloning, plasmids have been engineered to contain two things.
A number of convenient restriction sites and a marker gene to select for its presence in the host cell.
What carries 20kb, 50kb, and 300 kb of inserted DNA?
Baceriophage- 20
Cosmid- 50
BAC- 300
What are expression vectors?
They engineered to express a gene of interest to produce large quantities of the encoded protein.
What are libraries?
They are collections of cloned sequences that contain at least one copy of the entire DNA genome.
What is a cDNA library?
It contains complementary DNA copies of the mRNA in a cell.
How is cDNA prepared?
isolating mRNA from cells
synthesizing the complementary DNA using reverse transcriptase
and cloning the cDNA molecules into a vector
How do you isolate specific clones from a library?
By using a probe
What is a probe?
they are used to screen a library to recover clones of a specific gene
It is any DNA or RNA sequence that is complementary to the target gene of sequence to be identify.
