Biotechnology Unit
Stem Cells- Undifferentiated cells
Induced Pluripotent Stem Cells
Has potential but has not produced results comparable to embryonic stem cells.
An adult cell reprogrammed to become a pluripotent cell
Mulitpotent Stem Cells
Live in specific niches (ex: stem cells in bone marrow create all types of blood cells)
Replenish dying or damaged cells
Adult Stem Cells: can become only certain types of cells
Pluripotent Stem Cells
Embryonic Stem Cells from Blastula
Most controversial because obtaining ES kills the embryo
Most useful type of stem cell because they can be used to create any type of tissue or organ.
Totipotent Stem Cells
Zygotes: can become any body or placental cell
DNA Fingerprinting
Analysis of band patterns can be used for:
Identifying and cataloguing endangered species.
Paternity tests: Each band on a child's gel must be accounted for by the father or mother. If the father's band pattern does not account for the bands on the child's gel that the mother's does not have, he is not the father.
Crime scene investigations- matching evidence DNA with suspect DNA
Gel Electrophoresis: separates fragments by size
Each person has an individual band pattern, or DNA fingerprint. This is because VNTRs (Variable Number of Tandem Repeats) in the non-coding DNA are highly variable.
Smaller DNA fragments move faster because they weigh less, so the bands furthest from the start point contain the smallest fragments.
DNA fragments move across the gel when an electric current is applied. This is because one end of the gel is positive and one is negative. DNA has a negative charge so it is attracted to the positive charge at the other end of the gel.
Polymerase Chain Reaction: Amplify DNA fragments
Taq Polymerase adds complimentary bases to each strand
Heat separates DNA strands
Restriction Enzymes- create DNA fragments
Sticky ends: created with a staggered cut (ex: EcoR1)
Blunt ends: created with a straight cut (ex: Alu1)
Cut DNA at specific, usually palindromic sequences
Gene Therapy
In-vivo
Used to treat Cystic Fibrosis-- patients inhale the virus
Virus is administered to body and injects new gene into nucleus of cells while the cells are still inside the body.
Ex-vivo
Used to treat Severe Combined Immunodeficiency Disorder (SCID) by removing and treating blood stem cells in bone marrow.
Cells with mutated gene are removed from body, virus inserts new gene into nucleus of cells, cells are placed back in the body.
Virus Vectors
Virus inserts DNA with desired gene into nucleus to be transcribed and then translated into healthy protein
Virus transported into cell within a vesicle
Engineered to carry the desired healthy gene
DNA Sequencing
Human Genome Project 1990-2003
Sequenced an entire human genome
Ability to compare a patient's genes with a standard genome to determine which gene(s) may be mutated, causing a disease. This allows for more effective individualized medicine and gene therapy.
Differs from DNA Fingerprinting
Gives exact sequence of DNA rather than only size
Focuses on genes (coding DNA)
Transgenic/Genetically Modified Organisms
GMOs in Agriculture
Cons
Modified strains can grow in the wild and build super resistant weeds
May cause intended allergic responses in consumers
Plant resistance to bacteria builds up a human resistance to antibodies
Decrease in genetic diversity
Pros
Improve flavor and nutrition
Increase crop yield
Tolerance to heat, cold, drought
Tolerance to herbicide
Tolerance to pests
Bacterial Transformations
Steps:
6. Bacteria produce desired protein from inserted gene. (ex: human insulin)
5. you know that whichever bacterial colonies grow have taken in the plasmid with the desired gene because that same plasmid has antibiotic resistance.
4. Bacteria takes in plasmid that has antibiotic resistance gene and is grown on agar with antibiotics.
3. Use ligase to "glue" the desired gene into bacterial plasmid
2. Cut bacterial plasmid that has antibiotic resistance gene with same restriction enzyme used to remove desired gene.
1. Isolate and cut desired gene out of original organism's DNA with restriction enzyme
Plasmids used as vector for desired gene
