Biotechnology Flashcards
What is biotcehnology and 2 biotechnology techniques
- provide evidence for evolution
- the use of biological processes to produce useful products
- Polymerase Chain Reaction (PCR)
- Gel Electrophoresis
What is PCR?
- Polymerase Chain Reaction
- a technique used in molecular biology for producing multiple copies of DNA from sample.
- used in DNA fingerprinting, identifying diease
- allows small amounts of DNA to be replicated, producing testable amounts to use in analysis techniques
Description of three steps of PCR?
- PCR mimics the natural process of DNA replication that occurs prior to cell division
1. Denaturing: two strands of DNA separated
2. Annealing: short sections of DNA(primers) are bound to the separated strands
3. Extension: the short sections of DNA are extended to produce longer strands - sequence repeated 20-30 times - in a process called thermocycling
- takes two to three hours to produce about a billion copies of DNA
What is Denaturation?
- dna strands are headed to 94-96C, which break down hydrogen bonds holding strands together
- separates strand without disrupting individual strands
what is Annealing?
- temp decreased to appx 50-60C
- allows short strands of DNA called primers to bind to single DNA strands
- primers are complementary to either end of the targeted section of DNA to be copied, initiates replication
What is Extension?
- mixture heated to 72C
- Starting at primer, DNA polymerase reads DNA code and complementary strand is built, doubling number of strands.
- doubles number of strands, chain reaction = DNA amplififcation
What is Taq polmerase
- druing denaturing step, dna polymerase destroyned due to high temp
- a heat loving bacterium called Thermus Aquaticus forms a enzyme called Taq polymerase
- does not denature when heated,
What is an restriction enzyme
- cut DNA at specific base sequences leaving strands of various lengths which are distinctive from one person to the next.
- ## each enzyme has specific recognition site (dna sequence) which it will cut
Different restriction enzymes(sticky ends orblunt end) how they cut DNA
STICKY END
- dna cut is staggered
- sticky end is a stretch of unpaired nucleotides overhanging
- exposed strand can only re-join to DNA with complimentary-based pair-can be from different organism
- complimentary overhangs
BLUNT END
- cuts straight across DNA
- both ends terminate in base pair
- no overhangs
What is gel electrophoresis?
- process used to seperate charged molecules based on their size by pushing them through a gel
- technique able to separate DNA strands based on their length
Describe process of gel electrophoresis? 6 steps
- dna placed in wells in a semi-solid gel that is immersed into a solution of an electrolyte
- electrolytes at either end of gel
- negative electrode closest to DNA, positive opposite side
- electric current passes through gel, negatively charged DNA moves towards positive electrode
- smaller DNA piece move faster and further than larger ones
- the resulting pattern of bands is an individuals unique DNA profile, often called DNA fingerprint
What are 3 uses of gel electrophoresis?
- identifying hereditary diseases
- paternity tests,
- forensics
How does dna move in gel electrophoresis
-Dna will move through the gel rather than difuse through the solution
- DNA needs to be accurately filled in wells using micropipettes
How is a dna profile produced?
- using restriciton enzymes to cut DNA into smaller lengths that are separated by gel electrophoresis, using an electrical current to move DNA segments through gel at a rate proportional to their length
What is a dna ladder?
- often run at the same time as samples
- contains segments of DNA with known lengths
- results from unknown sample is compared to DNA ladder to determine length od DNA strands in the sample
