8.1 Flashcards
Insulin and Diabetes
Type 1 Diabetes:
- Body fails to produce enough insulin
Type 2 Diabetes:
- Body does not produce enough insulin, or cannot use the insulin produced
Risks factors: Genetic Predisposition and being overweight
How insulin was created
- Insulin was isolated by Banting and Best
▪ Helen Free invented a method to analyze blood sugar by “dip-test
urinalysis” (before this doctors had to taste patient’s urine…sweet = diabetes)
▪ This allowed people to monitor their blood sugar level at home
- Insulin was initially collected by the pancreas of pigs and cows (some were allergic)
- Scientist could insert human gene for insulin into bacteria (e-coli) to mass produced it
▪This is genetic engineering
▪ Bacteria are versatile tools for genetic engineers b/c they reproduce quickly, inexpensive to maintain, and contain plasmids
▪ Recombinant DNA is DNA of two species
Restriction Enzymes
- First step in genetic engineering is to cut out (isolate)
- DNA fragment that contains the desired gene
▪ Restriction enzymes cutting DNA at specific locations (recognition sites)
- Blunt ends – when cuts are made straight across the strand
- Sticky ends – when cuts are made in a zigzag
Restriction Enzymes
- Function to protect enzymes in which they are found
▪ E.g., can destroy viral DNA/RNA when injected into a
bacterial cell
▪ Restriction enzymes are highly specific and named
after its cell of origin,
DNA Ligase
- Enzyme that joins cut strands
▪ Works best with sticky ends of DNA
- T4 DNA Ligase works well with blunt ends
- Forms hydrogen bond b/w base pairs
▪DNA is not fully linked until the
phosphodiester bonds are formed along the backbone…DNA ligase does this via dehydration rxn
Plasmids
- Small circular pieces of DNA found in prokaryotes
- Replicate independant from chromosomal loop
- Often contain genes that code for specific proteins
Competent cell
▪a cell that can take up foreign DNA (e.g., E. coli)
Competent cell and Vector
Competent cell
▪a cell that can take up foreign DNA (e.g., E. coli)
Vector
▪a plasmid that has been designed to be a vehicle
for transferring foreign genetic material into a
cell
▪ The desired gene must be inserted into a specific
location in the plasmid
▪ The same restriction enzyme must be used on
both the source DNA and the plasmid so that they
will have the same sticky ends
▪ Recombinant DNA will now be introduced into a host cell (usually
bacteria), where it will make more copies of itself
Restriction Maps
- Plasma mapping
- Diagram that shows known restriction enymes and recognition sites
Transformation
- Successful introduction of DNA from another source is called
transformation
