Chapter 13 Flashcards
recombinant DNA
single DNA molecule containing DNA sequences from two or more sources
what role do restriction enzymes play in DNA manipulation?
cutting DNA into pieces
what role does gel electrophoresis play in DNA manipulation?
analysis and purification of DNA fragments
what role does DNA ligase play in DNA manipulation?
joins DNA fragments together in novel combinations
how can bacteria use restriction enzymes to defend against invasions
produce restriction enzymes that cut double-stranded DNA molecules into smaller, noninfectious fragments
restriction site
a specific sequence of bases where restriction enzymes cleave
in what manner do enzymes cut the DNA?
leave a short sequence of single stranded DNA at each end
what information about DNA can gel electrophoresis yield?
number of fragments, sizes of fragments, relative abundance of a fragment
DNA ligase
catalyses the joining of DNA fragments by making phosphodiester bonds between them
how are Okazaki fragments joined during DNA replication?
by DNA ligase
clone
produce many identical copies
transformation
inserting recombinant DNA into host cells
transfection
transformation but specific to when host cells are derived from an animal
transgenic
host cell or organism that contains recombinant DNA
selectable marker
helps grow only the transgenic cells
electroportaion
a short electric shock used to create temporary pores in the membranes through which the DNA can enter
replicon
segment of DNA that contains an origin of replication
vector
part of a carrier DNA sequence that the newly introduced DNA can enter the host cell with
plasmids
small, circular DNA molecules that replicate autonomously in many prokaryotic cells
reporter gene
any gene whose expression is easily assayed
genomic library
collection of DNA fragments that together comprise the genome of an organism
cDNA
complementary DNA
cDNA library
transcription pattern of the cells in the sample at a certain point in time
RT-PCR
using reverse transcriptase to make cDNA from RNA and then using PCR to amplify a specific sequence from the cDNA
homologous recombination
involves an exchange of DNA between molecules with identical, or nearly identical, sequences
stem cell
unspecialised cell that divides and differentiates into specialised cells
RNA interference
mechanisms for preventing mRNA translation
antisense RNA
RNA that binds by base pairing to the sense bases on the target mRNAs
why do siRNAs target specific mRNA molecules?
their sequences exactly match the target sequences in the mRNAs
what can miRNAs do since they do not match their targets perfectly?
reduce the expression of multiple, partially matching genes
expression vectors
vectors that also have extra sequences needed for the foreign gene to be expressed in the host cell
inducible promoter
responds to a specific signal
tissue-specific promoter
expressed only in a certain tissue at a certain time
signal sequences
can be added so that the gene product is directed to an appropriate desgination
pharming
the production of pharmaceuticals in farm animals or plants
advantages of recombinant DNA technology
ability to identify specific genes, ability to introduce any gene from any organism into a plant or animal species, ability to generate new organisms quickly
bioremediation
the use by humans of other organisms to remove contaminants from the environment
