Lecture 7 Flashcards
(38 cards)
What are the three essential features of a plasmid cloning vector?
Origin of replication (self-replication in host cells)
Dominant selectable marker (e.g., drug resistance gene)
Unique restriction sites for DNA insertion
Mnemonic: Picture a circular “plasmid” wheel with sections labeled “Replication,” “Resistance,” and “Insertion.”
What is positive selection in genetic manipulation?
Positive selection allows cells that have taken up a recombinant plasmid to grow (e.g., using antibiotic resistance).
Mnemonic: Imagine healthy green bacteria thriving on a petri dish labeled “Antibiotic,” while non-resistant bacteria die.
What is negative selection in genetic manipulation?
Negative selection identifies cells that lose something, such as toxin gene expression or β-galactosidase activity.
Mnemonic: Picture a red “STOP” sign on cells losing a trait, while others continue growing.
What is alpha complementation?
Alpha complementation detects recombinant plasmids by disrupting β-galactosidase activity.
Cells with active β-gal produce blue colonies.
Cells with disrupted β-gal (recombinant plasmid) produce white colonies.
Mnemonic: Picture a blue petri dish turning white where DNA is successfully inserted.
What is biofortification, and why is it important?
Biofortification enhances the nutritional content of crops to address micronutrient deficiencies (e.g., vitamin A, iron).
Mnemonic: Visualize rice grains glowing yellow with added nutrients, labeled “Vitamin A, Iron.”
What is Golden Rice?
Golden Rice is engineered to produce β-carotene (provitamin A), preventing blindness and child mortality in regions dependent on rice as a staple.
Mnemonic: Picture a bowl of bright yellow rice with an orange carrot logo.
What are the challenges of Golden Rice?
Opposition from groups like Greenpeace
Issues with technology transfer (patents, agreements)
Difficulty engineering local rice varieties
Mnemonic: Visualize a tangled web of paperwork around a golden rice stalk.
How is recombinant insulin produced?
Recombinant insulin is produced in E. coli vats using human DNA, eliminating allergic reactions seen with bovine insulin.
Mnemonic: Picture a bacterial factory labeled “Insulin Factory,” with vials labeled “Humulin.”
What are other medicinal recombinant proteins?
Examples include:
Factor VIII (haemophilia)
TPA (heart attack treatment)
Human growth hormone (pituitary dwarfism)
Mnemonic: Picture labeled medicine bottles with tags: “Clotting,” “Heart,” and “Growth.”
What are the risks of recombinant proteins in E. coli?
Post-translational modifications like glycosylation may be absent or incorrect in bacteria.
Mnemonic: Imagine a jigsaw puzzle where one piece doesn’t fit due to a missing glycosylation tag.
What is recombinant erythropoietin (EPO)?
EPO, a glycoprotein stimulating red blood cell production, requires expression in human cells or yeast to ensure proper glycosylation.
Mnemonic: Picture red blood cells being assembled by a robotic yeast arm.
What is genetic engineering?
Genetic engineering modifies DNA in living organisms to create new traits, often producing GMOs (e.g., bacteria that produce insulin).
Mnemonic: Imagine a scientist holding a glowing “gene wand” over a petri dish.
What are the types of artificial selection?
Selective breeding: mating for desired traits (e.g., racehorses).
Hybridization: combining traits from different organisms (e.g., Burbank potato).
Inbreeding: maintaining traits within a genetic line (e.g., purebred dogs).
Mnemonic: Picture a trophy shelf with a racehorse, a potato, and a dog statue.
What is cloning, and how is it performed?
Cloning creates a genetic copy of an organism.
Steps:
Remove the nucleus from an egg cell.
Insert a nucleus from a diploid body cell.
Stimulate the egg with electricity.
Implant it in a surrogate mother.
Mnemonic: Visualize a glowing egg with a lightning bolt charging it.
What are the benefits and risks of cloning?
Benefits:
Exact copies of organisms
Increased food supply
Medical transplants
Risks:
Reduced genetic diversity
High failure rate
Expensive
Mnemonic: Picture a conveyor belt of identical sheep labeled “Success” and one breaking down labeled “Failure.”
What is gene therapy?
Gene therapy delivers therapeutic genes to correct or treat disease, either in vivo (directly into the body) or ex vivo (modified cells reintroduced).
Mnemonic: Picture a tiny “gene capsule” being injected into a cell.
What is CRISPR/Cas9?
CRISPR/Cas9 is a genome-editing tool that uses a guide RNA to target specific DNA sequences for cutting or modification.
Mnemonic: Imagine scissors cutting a DNA strand, guided by a glowing “RNA map.”
What are vectors in gene therapy?
Vectors deliver therapeutic genes and include:
Lentivirus (LV)
Adenovirus (AV)
Adeno-associated virus (AAV)
Mnemonic: Picture a delivery truck with “LV,” “AV,” and “AAV” logos, unloading DNA packages.
What are the limitations of current gene therapy?
Gene therapy corrects somatic cells but does not prevent transmission to offspring. Germline modification is required for heritable changes.
Mnemonic: Visualize a family tree with a glowing red “X” over inherited diseases.
What are the three essential features of a plasmid cloning vector?
Origin of replication – Ensures self-replication in host cells.
Selectable marker gene – Confers traits like drug resistance (e.g., antibiotic resistance).
Unique restriction sites – Allows DNA insertion at specific locations.
Mnemonic: Visualize a circular plasmid with “Replication,” “Resistance,” and “Insertion” labeled.
What is positive selection in genetic manipulation?
Cells that take up the recombinant plasmid grow in the presence of a selective agent (e.g., antibiotics). Non-recombinant cells die.
Example: Antibiotic resistance genes in plasmids.
Mnemonic: A green petri dish with recombinant cells thriving while others are crossed out.
What is negative selection in genetic manipulation?
Identifies cells that lose a specific function or trait, such as toxin gene expression or β-galactosidase activity.
Mnemonic: A red “STOP” sign over cells losing specific functions.
What is alpha complementation?
Detects recombinant plasmids by disrupting β-galactosidase activity.
Active β-gal produces blue colonies.
Recombinant plasmids disrupt activity, producing white colonies.
Mnemonic: A petri dish with blue and white colonies.
What is biofortification?
Nutritional enhancement of crops to address micronutrient deficiencies.
Example: High-iron rice, Golden Rice (vitamin A), vitamin C-rich crops.
Mnemonic: Rice glowing yellow (β-carotene) with labels for vitamins.
