Bio 5: Biotechnology and gene technologies Flashcards
Asexual reproduction
+ve
Quick
Can be completed it sexual fails
Offspring have same genetic info
-ve
No genetic variation so there is weakness
Vegetative propagation
The production of structures in an organism that can grow into new individual organisms. These offspring contain the same genetic information as the parents and so are clones of the parent.
Tissue culture
The separation of cells of any tissue type and their growth in or on a nutrient medium. In plants undifferentiated callus tissues is grown in nutrient medium containing plant hormones that stimulate development of the complete plant.
Splitting embryos
Eggs and sperm is collected fork individuals that have the desirable characteristics ( eg high mild yield). It is fertilised in vitro. The cells grow to be an embryo and then split. These embryos are then implanted into multiple surrogates.
Nuclear transfer
Mammary cells are removed from an udder of a sheep
An ovum is removed from another
A mammary cell with a nucleus and the now enucleated egg are joined by electrofusion. This transfers the nucleus of the first sheep into the cytoplasm of the second.
It is put into culture, the early embryo is recovered and implanted into a ewe
Cloning
+ve
High value animals
Rare animals preserved
Genetically modified animals
-ves
Not always produced with welfare in mind
Hard to cope with environmental changes
Unclear of their future health
Non reproductive cloning
Replace tissue or organs
Eg- regeneration of heart muscle
Repair nervous tissue
Repair spinal cord
No rejection if from own tissue
End of donor lists?
Less dangerous
Any cell type - totipotent
Biotechnology
Technology based on biology and involves exploitation of living organisms or biological processes to improve agriculture, food science, medicine or industry
Production of food
Cheese and yoghurt: lactobacillus changes the flavour and texture of milk
Mycoprotein: growth of fungus in culture. Then separated and processed as food
Drugs and pharmaceuticals
Penicillin: fungus penicillin is grown in culture, produced antibiotic is a by product of metabolism
Insulin: E. coli modified to carry insulin gene. Secrets insulin
Enzymes and chemicals
Pectinase: fungus secretes pectinase
Calcium citrate: fungus makes citric acid as a by product of metabolism
Microorganisms in biotechnology
Grow rapidly
Often make chemicals that can be harvested
Can be genetically engineered
Grow well in low temps
Can be grown anywhere
Tend to generate more pure products
Can grow using “waste” or “toxic” materials
Culture
The growth of microorganism a. This make be a single species or a mixture of species.
Primary metabolites
Substances produced by an organism as part of its normal growth; they include amino acids, proteins, enzymes, nucleic acids, ethanol and lactate.
Secondary metabolites
Substances produced by an organism that are not part of its normal growth.
The antibiotic chemicals produced by a number of microorganism are almost all secondary metabolites
Normally after main growth period
Fermentation conditions
Temperature
Type and time of addition of nutrient
Oxygen concentration
pH
Batch culture
Starter population mixed with a specific quantity of nutrient, then allowed to grow for a fixed period. No further nutrient is added. At the end the tank is emptied
Continuous culture
Nutrients are added at intervals, and products are removed at intervals too.
Aseptic techniques
Any measure taken at any point in a biotechnological process to ensure that unwanted microorganisms do no contaminate the culture that is being grown or the products that are extracted
Immobilisation ( of enzymes )
Any technique where enzyme molecules are held, separated from the reaction mixture. Substrate molecules can bind to the enzyme and the products can go back to the reaction mixture, leaving the enzymes in place.
Immobilisation: adsorption
Mixed with immbolising support and bind due to the hydrophobic and ionic links.
adsorbing agents: clay, resins
Immobilisation: covalent bonding
Enzymes covalently bond to an insoluble matieral (eg clay) using a cross linking agent. Very strong.
Immobilisation: Entrapment
Trap enzymes in gel beads or cellulose fibre network. Not being bound to something leaves their active sites free, but reaction rates are reduced.
Genomics
Study of the whole set of genetic information in the form of DNA base sequences.
Sequencing genomes
- Genome is mapped, to see which part it came from
- Sample are sheared into 100,000 base pairs
- Placed into BACs and put in E.Coli
- Cells grow, and many clones are made
BACs
Bacterial artificial chromosomes
Comparing genomes
- Identification of important proteins found in all
- Shows evolutionary relationships
- Modelling effects of changes
- Identify disease causing sequences
- Show risk of disease
Electrophoresis
Separation of DNA by length
- DNA treated with restriction enzymes to cut them
- Put into wells at -ve electrode end of gel
- Immersed in buffer and electric current passed through for a fixed time
- DNA is -ve charged, so moved toward positive
- Shorter lengths more faster than longer, so therefore move further
- Can be shown by a staining dye
DNA Probes
Short single stranded piece of DNA, complementary to the section being investigated
It is labeled with a radioactive marker or a fluorescent marker
They anneal to the section of DNA
DNA
Anti-parallel backbone strands
5’ (prime) end and a 3’ (prime) end
Grows from 3’ end only
Base pair rules
Primers
Short single stranded DNA sequences.
Needed as PCR cannot work with only one strand of DNA.
PCR (polymerase chain reaction)
- DNA mixed with nucleotides and DNA polymerase
- Heated to 95C, breaks hydrogen bonds holding strands together
- Primers are added
- Reduced to 55C, allowing primers to anneal
- DNA polymerase can now bind
- Temp raised to 72, optimum for DNA polymerase to extend
- New double strand made
Automated sequencing
A modified nucleotide is added, the polymerase enzyme will stop when it reaches this. As the base of the modified nucleotide is known they know the complementary strands bases. This is repeated.
Restriction enzymes
They cut the DNA at specific points. They cut at restriction sites. This is normally catalysing a hydrolysis reaction breaking the sugar-phosphate backbone in different places. This gives a staggered end, leaving out a sticky end.
Sticky end
Formed when DNA is cut. It is a short run of unpaired exposed bases.
DNA ligase
Catalyses a condensation reaction which joins the backbones together
Transgenic
Contains DNA that has been added to its cells as a result og genetic engineering
Bacterial conjugation
Genetic material may be exchanged. Bacteria can do this themselves and this can result in antibiotic resistance spreading quickly.
Somatic Gene therapy: augmentation
Adding genes. Treats diseases that are caused by a faulty allele leading to loss of a functional polypeptide.
Somatic Gene therapy: Killing cells
Cancers can be treated by eliminating the cells
Germline gene therapy
Each early cell in an embryo is a stem cell. It could potentially become a new individual, therefore germline.
Engineering a gene into a sperm, egg, or early embryos means every cell has a copy of the new gene.
Somatic: issues
- Introduced into target cells, tecniques needed
- Short lived, repeated
- Difficulties getting allele into genome in functioning state
- Restricted to patient
Germline: issues
- Straightforward
- All cells has it
- Unethical (unknown if it has worked,or not, or changed something else)
- Can be passed on child
Liposomes
Small spheres of lipid bilayer containing a functioning allele. They can pass through the lipid bilayer of cells and therefore act as vectors.
Xenotransplantation
Transplanting of cells, tissues or organs between animals of different species
Allotransplantation
Transplanting of cells, tissues or organs between animals of the same species
