Biotechnology Flashcards
Biotechnology
- Modifying organisms, cells, and/or their molecules to achieve some result
- Using genetic information for diagnostics, treatment and crime solving
genetic engineering
manipulation of the genetic material of an organism to achieve some result
recombinant DNA technology
recombining” genes of different organisms to create an organism with new capabilities
most of our drugs are produced in
bacteria
How do we grow the drugs in bacteria
o Chop DNA from donor species (ex: human gene for insulin)
o Amplify the singly copy of DNA into many copies
o Insert the DNA into bacteria
o Grow the bacteria. As they grow, they will go through transcription and translation and produce the protein (insulin)
o Harvest the protein and purify it for use in humans
restriction enzymes
enzymes expressed by bacteria to protect themselves from viruses
recognize specific sequences of DNA that don’t exist in their own genome and cut the DNA there
cut DNA
process of restriction enzymes
- Cleaves dsDNA at specific sequences “restriction site”
- Restriction enzyme cleaves @ same place on both strands
- 1) Restriction enzyme cuts sugar-phosphate backbones
- 2) DNA fragment added from another molecule cut by same enzyme. Base pairing occurs
- 3) DNA ligase seals strands
vector
DNA molecules that can carry foreign DNA into a host cell and replicate there
how to amplify DNA
- Make many copies of a stretch of DNA
- Polymerase chain reaction
- Before PCR: had to harvest many many copies from many many cells
types of vectors
Bacterial plasmids and viruses for eukaryotic cells, transposons
plasmids
small circles of self replicating DNA
Recombination in Eukaryotes
- Bacteria take up DNA readily from the environment and replicate it on its own or integrate it into its 1 chromosome
- Barriers: caps and tails
- Mechanisms: viruses
first recombinant DNA techonology created insulin from
bacteria; before made from pigs and cows
Gene therapy
- Insert correct copies of genes that have mutations
- SCID: remove stem cells from bone marrow, insert correct copu of mutated gene using a virus, put stem cells back in
- Other diseases: cystic fibrosis, hemophilia, heart disease
problems with gene therapy
- Hard to get viruses to infect ONLY affected cells
* Hard to get viruses to infect enough cells for a ”cure” without triggering immune response
How do we analyze genomes to look for disease
• Use complementary binding to search a genome for a mutated disease or disease risk factor (how likely you are to get the disease)
Insecticide/herbicide resistance
allows farmers to spray their entire fields with chemicals to deter insects and weeds
insect resistance
take a gene from a plant that isn’t tempting to a certain bug, insert that gene into your crop. No chemical insecticide needed
Downsides to insecticide/pesticide
• Currently no evidence that the pesticide crystals are harmful to humans
• Insecticide sprays are toxic to the environment and can damage our water supplies
o May have public health effects
• Insects that pollinate these crops are affected by the genetic change. As these GMOs become more prevalent, the pollinating populations are dwindling
if a crop is resistant to a weed-killing chemical
you can spread it on the entire field and it will kill the weeds but not the crop
downside to spraying chemical on the entire field
o Leads to HUGE increase in herbicide use
o These resistant crops can cross-pollinate with other plants, spreading the gene that confers resistance
o The seeds from these plants can spread an be uncontrollable weeds in another farm
o Eventually many plants in a given geographical area will be resistant to the herbicide
o Several class-action lawsuits were recently brought against Monsanto to try to halt use of these GMOs
disparate effects
- Monarch butterflies do not consume crops (eat milkweed)
- Roundup ready crops leads to excessive roundup use, kills milkweed
- Milkweed dusted with pollen from Bt plants causes monarch to eat less
GMO Debates
- Risk to agriculture and environment are well-established and well-studied
- Risks include: gene flow, allowance of unsafe farming procedures
- What about risks to us if we eat GMOs?
Facts of GMO
- No established disease risk by eating GMOs
- GMO labeling and bans are in place in Europe, Australia brazil china and Russia
- Concerns include: disease risk and allergies, transfer of genes to gut bacteria, presence of bacteria or fungal proteins expressed in foods
- Potentially GMO foods: corn, soybeans, alfalfa for animal feed, some tomatoes, some potatoes, some canola for oil
Bovine
o Bovine growth hormone given to cows to increase their milk production by 15%
o Causes udder infections called mastitis
o Cows treated with rBST are also treated with antibiotics
Bioremediation
- Using microorganisms to clear pollutants from the environment
- Deepwater horizon oil spill: 800 million L of oil, disappeared faster than exxon valdez 41 million L in 1989
- Gulf of Mexico has a vastly richer microbial ecology due to temp and natural oil seepage
- Within 24 hours, the oil eating bacteria populations had grown 10-fold
Using GMOs for Benefit
- Enable livestock to make recombinant molecules, instead of bacteria
- Advantage: we make immune reactions agains bacterial proteins. If not pure, injection of recombinant material can cause deadly immune reactions
Cloning
- Take the nucleus from a somatic cell (diploid)
- Insert it into a gamete cell (with nucleus removed)
- Create a new organism that looks identical to the parent (similar to parthenogenesis)
Downsides to Cloning
- Difficult: must “turn on” genes that have been turned off (fate of dolly)
- All the downsides to asexual reproduction
Upsides to Cloning
- Genetically engineer the perfect animal for a purpose
* Instead of re-engineering each subsequent animal, just clone
Crimes and Relationship Testing
- Use restriction enzymes to digest DNA into fragments
- Fragment sizes will be unique to an individual, bc DNA sequence determines location of cuts
- Fragments of different sizes, called “DNA fingerprint”
Personalized medicine
- Clinicians diagnose disease based on a set of symptoms
- Ex: melanoma
- A variety of genetic changes lead to the same symptoms
- Screen patients (and/or their tumours) to find out the specific mechanism of their disease
- Ex: roche’s zelboraf
- In melanoma tumors with a specific mutation (about 60% of melanoma patients), triggers cell death
- 80% cure/regression rate
- a few drugs on the market are beginning to work this way
mechanisms of personalized medicine
- Biopsy tumor
- Full genetic analysis via drawn blood
- Dedifferentiated stem cells?
controversy of personalized medicine
- Expense
* Insurance companies must pa
