modern applications of microbial genetics Flashcards
what is biotechnology
using living systems to benefit humankind, direct alteration of an organisms genetics to achieve desirable traits
what does genetic engineering involve
the use of recombinant dna technology
what is recombinant dna technology
the process where dna sequence is manipulated in vitro creating recombinant dna molecules that have new combinations of genetic material
what is transgenic
when dna is entered into a different host species the host organisms is transgenic
what is an example of transgenic bacteria
insulin from humans being inserted into a plasmid and then into bacteria allowing them to produce and secrete human insulin
how do prokaryotes acquire foreign dna
conjugation
transduction
transformation
what was the first molecular cloning
when cloned genes from the African clawed frog was inserted into bacterial plasmid that was then introduced to e coli
what is molecular cloning
methods to construct recombinant dna and incorporate it into a host organism
what are dna molecules manipulated with in recombinant dna
naturally occurring enzymes derived from bacteria viruses
what makes recombinant dna possible
restriction endonuclease (restriction enzymes)
what are restriction enzymes
bacterial enzymes produced as a protection mechanisms to cut and destroy foreign cytoplasmic dna mostly from bacteriophage infection
how are restriction enzymes used
to cut dna fragments that can be spliced into another dna molecule to form recombinant molecules
what is a recognition site
a specific usually palindromic dna sequence between four to six bace pairs
what is a palindrome
a sequence of letters that reads the same forward as backwards, same sequences in the 5’-3’ to 3’-5’
what does it mean to anneal
form hydrogen bonds between complementary bases at their sitcky ends
what does annealing allow
hybridization of the single strand overhang
why dont blunt ends attach as well as sticky ends
lack of complementary overhangs facilitating the process
what is hybridization
joining together two complementary single strands of dna
how are single strands rejoined
ligation, dna ligase rejoins the two-sugar phosphate backbones through covalent bonding
what are plasmids
small pieces of double stranded dna that replicate independently of the bacterial chromosome
what is a vector
dna molecules that carry dna fragments from one organism to another, usually plasmids
what is a polylinker site
a short sequence containing multiple unique restriction enzyme recognition sites used for inserting dna into the plasmid after restriction digestion of dna and the plasmid
what does having multiple restriction enzymes recognition sites within a polylinker do
makes plasmid vector versatile so it can be used for different cloning experiments with different restriction enzymes
where is the polylinker site found
within the reporter gene
what is the reporter gene
a gene sequence artificially engineered into the plasmid that encodes a protein that allows for visualization of dna insertion
what does the reporter gene allow researchers to do
to distinguish host cells that contain recombinant plasmids with cloned dna fragments from host cells that only contain nonrecombinant plasmid vector
what is the most common reporter gene
lacZ gene
what does the lacZ gene encode
beta galactosidase
what does beta galactosidase do
degrades lactose and synthetic analog x-gal
what is shown on x-gal containing colonies
blue colonies
when is the lacz gene disabled
when recombinant dna is spliced into the plasmid
what is the most commonly used mechanism for introducing engineers plasmids into a bacterial cell
transformation
what is transformation
when bacteria takes up free dna from their surrounding
where does free bacteria come from in nature
lysed bacterial cells
where does free dna come from in the lab
from recombinant plasmids introduced into the environment
how is a cell made more competent
by increasing the permeability of the cell membrane
how do you increase the permeability of the cell membrane
chemical treatments that neutralize charges on the cell membrane or exposing bacteria to an electric field that makes microscopic pores in the cell membrane
come back to molecular cloning
what is a genomic library
a complete copy of an organisms genome contained as recombinant dna plasmids engineered into unique clones of bacteria
what is the purpose of a genomic library
allow researchers to creat large quantities of each fragment to determine sequence and function of any genes
