Ch 6 Flashcards
how do we map species genomes?
DNA sequencing
how can you identify the unique genetic makeup of individuals?
DNA profiling
what are the applications of recombinant DNA technology?
agriculture and environmental conservation
biotechnology
the use of living things to make new products or systems e.g. using yeast to ferment wine
Genetic engineering is…
change the genetic sequence of an organism using biotechnology techniques
what are organisms created to benefit human use called
Genetically Engineered Organisms (GMOs) or transgenic organisms
what do restriction enzymes do
cut DNA at specific restriction sites into smaller pieces called restriction fragments
different restriction enzymes have different restriction sites & most recognition sequences are complementary segments of DNA
what are sticky ends and blunt ends?
types of cuts formed from restriction enzymes, sticky ends have overhanging steps while blunt ends do not (clean cut)
what’s DNA ligase
an enzyme used to join different pieces of DNA together
What does PCR stand for and what are the steps?
Polymerase chain reaction
1 - denaturation
2 - annealing
3 - extension
why would you need PCR
Eukarotic somatic cells have only 2 copies of a gene of interest and prokaryotic cells only have one copy therefore only a small sample is available for analysis
PCR will increase the amount of DNA available for analysis
what components are required for PCR
DNA template to be copied
DNA polymerase
Buffer solution containing salts
A supply of nucleotides (A, G, C, T)
2 primers (these are the starting point where DNA polymerase can add new DNA nucleotides)
Denaturation
DNA is heated to 95oC, breaking H-bonds between the bases, causing denaturation (aka melting stage)
Annealing
temp is reduced to 50-60oC, allowing primers to anneal (join) to complementary sequences. Base pairing occurs and the formation of new H-bonds
Extension
temp is raised to 72oC, optimum temp for DNA polymerase used in PCR. Starting at primers, new DNA strands are synthesised…results in 2 copies of DNA.
what are the 3 ways we can visualise DNA
separate the fragments according to size (gel electrophoresis)
DNA fragments can be identified using a DNA probe
nucleotide sequence can be analysed using DNA sequencing
gene probe
a molecular tool that is used to search for a specific gene sequence within the genome
how does gel electrophoresis seperate DNA?
because the phosphate group of DNA is negatively charged, the molecule will migrate towards the positive electrode.
the SMALLER the fragment the further it migrates
DNA can be identified by comparing to known samples
how does DNA sequencing assist scientists
DNA sequencing determines the exact nucleotide sequence of a gene therefore helps scientists identify mutations (deletions/substitutions) in an individuals genome (eg. cystic fibrosis/sickle cell anemia)
what can transferring genes be used for
for gene therapy, useful genes resistant to disease etc…
a gene of interest can be inserted into a vector that will carry the gene/DNA to the desired organism
what vectors can be used for gene therapy
plasmids
viruses
liposomes
what process involves DNA being incorporated into the DNA of another organism
ligation
how can scientists isolate specific genes
using restriction enzymes
what are Short Tandem Repeats (STRs)
sections of non-coding DNA that are repeated many times
