Applications of Reproduction and Genetics - Finished Flashcards
What is the definition of a clone?
Genetically identical individuals from a single parent.
Give an example of natural cloning in plants
Asexual reproduction - Spider plants/ Strawberries (runners)
Daffodils (Bulbs)
Give an example of natural cloning in animals
Identical twins. Blastocyst splits forming two identical smaller blastocysts
Give examples of how reproduction is used in industry
Embryo Splitting (Cattle) Sperm from the prize bull and an egg from the prize cow make a zygote which produces an embryo made up of undifferentiated cells. The embryo is split to make more identical embryos which are then implanted into lower quality cows. The calves will be good quality calves because their genes are from the prize animals
What was Dolly the Sheep?
A cloned sheep
What was dolly the sheep cloned from?
Megan - A sheep who was genetically modified to produce HGH - Megan was cloned to ame sure that the HGH producing gene was passed onto her offspring
How do you clone?
Nuclear transplantation-
Take a body cell from the sheep that you want to clone and an egg cell from another healthy sheep. Take the nucleus out of the egg cell and place the nucleus from the body cell in its place.
Trigger the division of the cells with chemical and electrical stimulation
If it works it should form an embryo which is then implanted into a third sheep.
What is one disadvantage of Nuclear Transplantation?
Doesn’t reset the “biological / Chromosomal clock” to 0
Animal has a shorter lifespan because it’s chromosomes are old.
What are stem cells?
Undifferentiated/unspecialised cells capable of dividing and specialising into any specialised cells
Embryonic stem cells are the best source of stem cells because they can be specialised. Give an advantage and disadvantage.
Advantage - potential to become any human cell type
Disadvantage - End of a potential life
In what diseases are stem cells used for treatment?
Alzheimer’s - regrow brain tissue
Parkinson’s
Diabetes - Into pancreas to grow tissue that makes insulin
Why do we use adult stem cells?
To overcome the problem of controversy surrounding embryonic stem cells
Means there is not loss of potential life.
Give and advantage and disadvantage of the use of adult stem cells
Advantage - No issue of tissue rejection (assuming the stem cells come from the same person)
Disadvantage - Cells are only part specialised
What is micropropogation?
cloning of plants
What does Totipotent mean?
Potential to become any other plant cell type
What plant cells are NOT totipotent?
Xylem and Phloem
What is micropropogation used for?
It is used to culture lots of agriculturally/horticulturally important plants - Bananas
What is the plant equivalent of a stem cell?
Meristematic tissue (Meristem - Growing point of a plant)
What is a callus?
Undifferentiated cell mass
What does micropropogation involve?
1- Cut a growing point of a plant
2- Place meristem onto agar (o2 h2o and nutrients)
3- Callus can be split to get more pieces and grow more calluses
4- Calluses grow in a medium containing plant hormones. Callus tissues differentiate growing into roots and leaves - NOW CALLED AN EXPLANT
5- Then grows until can be planted into the ground
Give some advantages of micropropogation
- Genetic stability as produced by mitosis, guaranteed to be the same
- HUGE PRODUCTION RATE - Small space required so you can produce 10,000’s of clones
- Quick process
Give some disadvantages of micropropagation?
- Genetically identical - All susceptible to same diseases or change in conditions
- Microbial contamination
What does transgenic mean?
Transferal of genes/DNA from one species to another
Give examples of GM plants
GM soya - resistant to herbicide
Tomato - “Flavrsavr” contains fish DNA - transcribed into mRNA - sequences block a naturally occurring mRNA that produces ripening enzyme
Banana’s - Vaccines
crops - Natural insecticides - cotton
What is a marker gene?
Used to show that a plant has taken up genes
- Plants - Herbicide resistance gene
- Bacteria - Glow in the dark gene
How is a gene transferred into another plant?
- Identify gene to be transferred
- cut the gene out using restriction enzymes (from viruses)
- use agrobacterium bacteria to insert gene into plasmids (crown gall forming gene - tumour gene)
- Expose a plant callus to agrobacterium - insert its plasmids into plant tissue - inserts the DNA
What are the advantages of GM crops?
Insert beneficial genes - Improved storage, Health benefits, reduced use of agrochemicals (no bioaccumulation)
Increased yields/ economical value
What are the disadvantages of GM crops?
Passes genes onto related species (pollen)
Long term health risks
Negative effect on wildlife? (Bees)
What is the Human Genome Project?
Project to identify all of the DNA/alleles/genes in an individual
sequence the DNA
Who was involved in the HGP?
Governments
Drug Companies - wanted to identify Parkinson’s, Alzheimer’s and Diabetes genes and make treatments -> ££££
What is Somatic Cell Therapy?
Gene therapy , used to treat Cystic Fibrosis
What is cystic fibrosis?
caused by recessive gene which causes thick mucus in the lungs which block airways and cause bacterial build up.
In cystic fibrosis the transport protein pumps that pump salt into the lngs doesn’t work meaning water does not diffuse into the lung and thin the mucus.
How is cystic fibrosis treated by somatic cell therapy?
Breathe in the dominant normal allele, wrapped in liposome - can cross cell membrane.
What is a problem with somatic cell therapy?
Only treats certain organs
What is the advantage of using germ-line therapy/ germinal cell therapy?
treats the embryonic stage - very few cells - easier to treat?
What is genetic engineering used for?
bacteria producing HUMAN insulin
How does a restriction enzyme work?
Cuts after a specific sequence of bases AATT. Leaves sticky ends. Gene and the sticky ends are inserted into the plasmid using DNA ligase and the Sticky ends join with the plasmid.
How is an insulin gene identified/made?
Use mRNA complimentary to the DNA sequence
mRNA converted to (single strand of DNA) by reverse transcription (enzyme - reverse transcriptase - viral enzyme)
Single strand of DNA converted to 2 strands of DNA (DNA molecule) (enzyme - DNa polymerase)
Insulin gene!
Insert into plasmid
ONLY GOOD IF YOU NEED ONE GENE OR ONE POLYPEPTIDE
