Manipulating genomes chp 21 Flashcards
define genetic engineering
manipulation of the genome
define genome
all the genetic information found within an organism
define transgenic
organism that carriers a gene from another organism
from another species
what type of enzymes are used in genetic engineering
- restriction endonuclease
- DNA ligase
what is the function of restriction endonuclease
- cuts required gene from DNA
- cuts open DNA in host organism
define sticky ends and why are they made
- regions with unpaired, exposed bases
- many restrictions endonuclease cut the DNA strand unevenly, leaving strand fragmented
why do we want sticky ends to be produced during genetic engineering
make it easier to insert desired gene into the DNA
how can mRNA be used for genetic engineering
- isolate mRNA for desired gene and using enzyme reverse transcriptase to produce strand of complementary DNA
what enzyme is used in genetic engineering involving mRNA
reverse transcriptase
what advantages are there of using genetic engineering involving mRNA
- its easier to identify desired gene, as particular cells will make some very specific types of mRNA
^beta cells in pancreas make insulin mRNA
define recognition site
genetic sequences where the restriction enzymes cut the DNA segments
define vector in genetic engineering
something that carries the isolatyed DNA into the host cell
what are some common used vectors in genetic engineering
- plasmid DNA
define plasmid DNA
small circular molecules of DNA separate from chromosomal DNA that can replicate independently
define recombinant DNA
when isolated DNA combines with host DNA
what Is the function of DNA ligase in genetic engineering
forms phosphodiester bonds between the sugar and phosphate groups on two strands of DNA
define marker gene
a gene used to determine if DNA sequence has been successfully inserted into an organism’s DNA
How can marker genes be used to test if the gene insertion has been successful
- have characteristic that can be used to see if insertion done correct
- common one is antibiotic resistance, bacteria then grown in antibiotics (if survive then done correctly)
define transformation in genetic engineering
process of transferring recombinant DNA into host cell
define electroporation
- small electrical current applied to bacteria
^ this makes membrane porous so plasmids can move into cell
what is a problem with electroporation
if too much electrical current used can destroy whole cell
define electrofusion
- tiny electric currents are applied to membranes of 2 different cells
^this fuses cell and nuclear membranes to form polypoid cell
what is electrofusion used for
- producing monoclonal antibodies
what are genetically engineered prokaryotes used for
produce:
- hormones (insulin, HGH)
- clotting factors
- antibiotics
- pure vaccines
what are the pros of genetic engineering in plants
- drought resistance
- higher yeilds
- producing herbicides & pesticides (so dont need to be sprayed)
- can improve nuitritional value
- reduces economic costs and carbon foot print
what are some cons of genetically engineered plants
- could have adverse side effects
- could have unknown effects
- may limit biodiversity as out compete local wildlife
- cross pollunation could lead to superweeds
- patents can create monopolies (high prices)
what form of transformation is used to genetically engineer plants
- electrofusion
why is it hardest to genetically engineer eukaryotic animals cells in particular
- cell membranes are hard to manipulate
what are the steps to genetically modify plant cells
- cut lear
- expose cells to bacteria carrying desired gene and marker gene (antibiotic resistance)
^allow bacteria to deliver genes - expose leafs to antibiotics
- ones that survive have desired gene, let them multiple & form clump
- allow callous to grow shoots + roots
- transfer plant to soil
- what percentage of DNA codes for proteins
- 2%
- what is non-coding DNA called
- What is coding DNA called
- introns
- exons
what are some uses for DNA profilling
- paternity test
- forensic identification at crime scenes
- Diagnosing genetic diseases
what are the 2 sub-groups within non-coding DNA
- VNTR (variable number tandem repeats ) also called minisatillites
- STR (short tandem repeats) also called microsatilistes
- What type of DNA is used for DNA profilling
- why is this
- introns as exons
- using coding sequence of DNA would not provide unique proflies
what are the stages of DNA profilling
- extract DNA
- amplify it using PCR (artifical DNA replication)
- cut DNA using restriction endonuclease
- place DNA into wells on gel electrophoresis plate
^seperate DNA based on mass - Dye DNA using fluroescent/radioactive dye and view under X-ray/UV
what does PCR do
- makes more DNA
Explain process of how PCR works
- heat up DNA to break hydrogen bonds
- cool solution slightly so can add primer
- DNA polymerase (from bacteria in hot climates) used to speed up PCR
^solution heated to optimum temp for this
What is a primer in PCR
- short sequence of DNA bases that are complmentary and specific to part of DNA you want to copy
