plant,animal, medical btech Flashcards
(23 cards)
What is inbreeding in plant breeding?
Selecting the most desired offspring and breeding within a population to maintain traits.
Allows recessive traits to appear and be retained.
Define hybridisation (cross breeding).
The crossing of two plants that have genotypes.
Genotypes refer to the specific combinations of genes that determine the characteristics being bred for in the plants.
What is hybrid vigour?
Often produces a strain that grows better than either parent as inbred mutations are masked.
How are hybrids typically propagated?
Often hybrids are infertile, parent stocks are re-crossed each year or propagated by cuttings.
What is back-crossing?
Offspring exhibiting a desired characteristic are continuously crossed with just one parent.
What are the limitations of conventional breeding?
Powerful but slow, some boundaries are difficult to cross, loss of biodiversity.
What is a gene gun?
A method that uses microparticles coated with DNA that are shot into plant cells to deliver foreign DNA.
Describe how Agrobacterium tumefaciens causes tumors in plants.
Inserts its DNA into plant cells, causing tumours through natural transformation.
What is the Ti plasmid?
A special piece of DNA in Agrobacterium that helps insert bacterial DNA into plant cells.
List the three key types of genes on the Ti plasmid.
- Genes for plant growth hormones (cytokinins and auxins)
- Genes for making bacterial food
- Vir genes that help transfer bacterial DNA into plant cells
True or False: Agrobacterium is effective at infecting monocots.
False.
What is the advantage of glyphosate-resistant soybeans?
Allows crops to survive glyphosate application while killing weeds.
What is the main disadvantage of using genetically modified strains?
Decreased biodiversity.
Fill in the blank: Transgenic animals are created by introducing _______ into their genome.
foreign DNA.
What is the purpose of antisense RNA?
Blocks translation by binding to mRNA and preventing it from being read by ribosomes.
What is the typical progression in drug discovery?
- Lead compound
- Tissue culture
- Animal tests (preclinical trials)
- Human tests (clinical trials)
What was the outcome of the sulfanilamide incident?
Led to the establishment of the FDA to set international standards for food and medicine safety.
What ethical issue was highlighted by the Tuskegee syphilis study?
Lack of informed consent in human testing.
What is the purpose of Phase 1 clinical trials?
Check for safety and dosage.
What are the objectives of Phase 2 clinical trials?
Check for efficacy and side effects.
What is a chimera in the context of transgenic animals?
An organism that has a mixture of normal and recombinant cells.
How do researchers create a transgenic mouse?
By introducing foreign DNA through pronuclear microinjection or transformation of embryonic stem cells.
What is the significance of the dominant coat colour gene in transgenic mouse selection?
Used as a selectable marker to identify offspring expressing the transgene.
