Biotechnology Flashcards
What is recombinant DNA?
a molecule of DNA that contains nucleotides from different sources
What is exogenous DNA? Where is this DNA involved?
the DNA of another organism
involved in genetic engineering where DNA of one organism is manipulated in order to insert the DNA of another organism
What are genetically engineered organisms used for?
- study the expression of a particular gene within a species and between species
- investigate cellular processes
- study the development of a certain disease & discover new treatments
How is a Gel electrophoresis prepared?
- DNA is cut by a restriction enzyme
- Fragments of various sizes are produced, and the DNA is negatively charged
- Fragments move through an agarose gel medium towards the positive side
- Smaller pieces travel farther & larger pieces travel slower and lag behind
- A stain called ethidium bromide is applied to the DNA allowing the fragments to be visualized and the gel pattern analyzed
What is Gel electrophoresis? Where is it used?
a method where an electric current is used to separate DNA fragments according to the size of the fragment
used to study DNA fragments various sizes; used to analyze DNA samples and create a DNA fingerprint for identification
What is gene cloning? Where is it used?
used to make many identical copies of a gene; produces large numbers of recombinant DNA molecules
- bacterial cells are mixed with a recombinant plasmid DNA, some of the bacterial cells take up the recombinant plasmid DNA through transformation
used to create large amounts of recombinant DNA to be used in genetically engineered organisms (further studies)
What is DNA sequencing? Where is it used?
identifies the DNA sequence of cloned recombinant DNA molecules for further study
used to identify errors in DNA sequence, to predict the function of a particular gene, and to compare to other genes with similar sequences from different organisms
What is PCR - polymerase chain reaction? Where is it used?
makes copies of specific regions of sequenced DNA
used to copy DNA for any scientific investigation including forensic analysis and medical testing
What are transgenic organism
organisms that are genetically engineered by inserting a gene from another organism
Why is everyones DNA pattern different?
due to sections of junk DNA (introns)
- does not code from proteins
- made up of repeated proteins
- many sites on our 23 chromosomes with different repeat patterns
How can the results of the gel electrophoresis be used to identify different individuals?
each person may have different number of repeats
What are DNA fragments from gel electrophoresis compared by? and for which purpose?
compared by size
purpose: forensics, medical diagnostics, paternity, evolutionary relationships
What is CRISPR - clustered regularly interspaced short palindromic repeats?
a gene modification system that edits DNA using an enzyme isolated from bacteria, called Cas 9, which was originally used to protect from viruses
What are transgenic bacteria? What do they do?
- insulin, growth hormone, and substances that dissolve blood clots are made by transgenic bacteria
- transgenic bacteria slow down the formation of ice crystals on crops to protect them from damage, clean up oil spills more efficiently, and decompose garbage
What are transgenic plants? What do they do?
genetically modified crops (ex. soybeans, corn, canola, tomatoes, potatos; they have an increased tolerance to herbicides and/or greater resistance to disease and pest infestations
- contribute to increased crop yield, reduction in harvesting cost and pesticide use, and enhanced nutritional value and food quality
What are transgenic animals?
animals produced in laboratories for biological research (a foreign gene is deliberately inserted into their genome)
- some animals are used to study diseases and how to treat them
- ex. transgenic goats: produced a protein antithrombin III which is used to prevent human blood from forming clots during surgery
- Future transgenic organisms might be used as a source of organs for organ transplants
What are the 3 tools of biotechnology?
- endonucleases (restriction endonucleases)
- methylases
- DNA ligase
What are endonucleases?
- found in bacteria; cleave DNA at specific target sequences
- double cuts cause overhanging pieces of DNA called sticky ends (contain single stranded DNA)
- another piece of DNA cut with the same enzyme will be able to bond through complementary base pairing and create a recombinant DNA molecule
- ex. EcoRI - cuts DNA containing the sequence GAATTC
What are methylases?
- enzymes that add methyl groups (-CH3) to specific DNA sites
- this prevents restriction enzymes from cutting the DNA
- this can protect gene fragments from being cleaved within a coding region
What is DNA ligase used for in biotechnology?
- used for joining the cut strands of DNA together
- removes a molecule of water and reforms the sugar-phosphate bonds in the DNA backbone
- T4 DNA ligase isolated from a bacteriophage is commonly used for this purpose
How does CRISPR work?
- uses a guide RNA (gRNA) to target specific sequences
- Cas 9 acts as molecular scissors to cut the DNA at targeted sites, allowing scientists to edit, replace or delete specific genes
key parts:
- guide RNA: directs Cas 9 to the precise DNA sequence to be edited
- Cas 9: cuts the DNA at target location
- Donor DNA (optional): used to insert a new genetic sequence during editing
- CRISPR array: stores genetic memory of prior infections in the natural bacterial system
What are CRISPER’s benefits for society?
- medical advancements: can correct genetic diseases like sickle cell anemia or cystic fibrosis
- cancer research: helps identify and target genes driving cancer
- agriculture: creates disease-resistant and higher-yield crops
- environmental applications: modifies organisms to combat pests or pollution
What are CRISPR’s disadvantages for society?
- Ethical concerns: risk of misuse, such as “designer babies”
- Off-target effects: unintended edits could cause harmful mutations
- safety concerns: long-term consequences of gene-editing are unknown
- Accessibility: high costs may limit its benefit to wealthier populations
What can CRISPER not do yet?
- Precise targeting: prevent all off-target edits
- Fix all genetic diseases: some are too complex or involve multiple genes
- Long-term studies: provide definitive answers about safety over generations
- Edit mature cells effectively: editing certain cell types, like neurons, remains a challenge
