3.5 GENETIC MODIFICATION AND BIOTECHNOLOGY Flashcards
GEL ELECTROPHORESIS
restriction enzymes
fragments are placed into small depression or wells at one end of the gel.
An electrical current is applied to the gel (positive on one side and negative on the other).
The fragments of DNA will fall out and embed in the gel based on their size and charge.
The smallest particles that are charged go the farthest in the gel, while the large non-charged particles fall out and embed in the gel the quickest.
BEFORE GEL ELECTROPHORESIS
restriction enzymes are used to cut DNA into fragments of various lengths and different charges
RESTRICTION ENZYMES
cut DNA into fragments at specific base sequences in each sample.
PCR
is a laboratory technique that takes a single or few copies of DNA and amplifies them to generate millions or more copies of a particular DNA sequence.
PCR STEPS
Denaturation
Annealing
Elongation
DENATURATION
DNA sample is heated to separate it into two strands
ANNEALING
DNA primers attach to the opposite ends of the target gene sequence
ELONGATION
A heat-tolerant DNA polymerase (Taq polymerase) copies the strand
DNA PROFILING
is a method or technique used to identify individuals on the basis of their DNA profiles in comparison to an unknown sample of DNA.`
DNA PROFILING USE EXAMPLES
paternity test to identify the biological father of a child. Scientists can take a blood sample which contains a father’s DNA and a blood sample from a child which contains the child’s DNA. They can then run a gel electrophoresis to compare the banding patterns between the father and the child.
criminal investigations where a small sample of blood, semen, hair or other cells where DNA is present is collected.
DNA PROFILING PROCESS
PCR can be applied to these small samples of DNA to amplify the DNA into millions of copies to create enough DNA to be analyzed for the investigation.
Using restriction enzyme to cut the DNA into fragments that are separated through gel electrophoresis and DNA profiling, the DNA sample can be compared to a suspect’s DNA to prove if they are innocent or guilty.
DNA profiling can also be used to support ancestral relationships between organisms for evolutionary studies.
Fluorescent marker may be added to show the colour.
GENETIC MODIFICATION
A gene produces a certain polypeptide in an organism.
Since the genetic code is universal, when a gene is removed from one species and transferred to another the sequence of amino acids in the
polypeptide produced remains unchanged.
GENE TRANSFER
Gene transfer is taking one gene from an organism and inserting it into another organism.
GENE TRANSFER EXAMPLE
An example of gene transfer is for the production of human insulin produced by the pancreatic cells.
GENE TRANSFER
INSULIN PRODUCTION
First, insulin production genes are cut off using restriction enzyme.
Use the same restriction enzyme to cut the bacteria plasmid open
Place the gene into the plasmid using DNA ligase. (antibiotic resistance may also be put in to make the plasmid attractive)
Put the plasmid back in the bacteria.
Bacteria go through replication and production of human insulin.
Harvest and purify the insulin.
