Unit 3.5 Genetic Modification and Biotechnology

what is gel electrophoresis?

a lab technique used to seperate and isolate protein or DNA fragments

how does gel electrophoresis work?

samples are placed in a block of gel and an electric current is applied causing the samples to move through the cell

do smaller samples move faster or slower through the gel in electrophoresis. why?

faster because they’re less impeded by the gel

why do samples of different sizes separate?

they have different sizes so move at different speeds

what enzyme is used to cut DNA into fragments?

restriction endonuclease

Is DNA positively or negatively charged. why?

Negative due to the phosphate group

how does DNA seperation work?

DNA samples are placed in agarose gel and fragment size is calculated by comparing against industry known standard

what is a polymerase chain reaction (PCR)?

artificial method of replicating DNA under lab conditions

what are the three stages if a PCR?

1. denaturation - at around 95 degrees the DNA sample is heated to seperate it into two single strands that act as templates
2. annealing - at 55 degrees samples cool allowing DNA to bind to the 3’ end of the sequence
3. elongation - at 72 degrees a heat tolerant DNA polymerase (Taq) binds to the primer and copies the strand

what is DNA profiling?

a technique that examines variable portions of DNA to create a profile that’s unique to an individual

what is satellite DNA and where’s it found?

long stretches of DNA made of repeating elements called short tandem repeats and are found in the non-coding regions f an individuals genome

what is the process of DNA profiling?

1. DNA collected
2. amplifies using PCR
3. satellite DNA is cut with restriction enzyme to generate fragments
4. fragment length differs between individuals due to varying length so short tandem repeats
5. fragments seperated using gel electrophoresis to compare profiles

what is gene transfer?

transferring genes between species

what is the new organisms called when genes have been transferred?

transgenic

what it the process of transferring genes?

1. DNA is isolated from cell by centrifugation then the gene of interest is amplified by PCR, then theres a vector that will carry the gene usually a plasmid
2. digestion with restriction enzyme - the DNA and vector are cut using a restriction enzyme, it cuts the sugar phosphate backbone to create blunt ends or sticky ends
3. gene of interest is inserted into the plasmid then the gene and vector are spliced and DNA ligase joins the gene and vector by fusing the sugar-phosphate backbones together by a covalent phosphodiester bond

what’s the difference between sticky ends and blunt ends?

sticky ends have a few unpaired bases so scientist cut the vector to ft the sticky ends

blunt ends dont have any unpaired bases

advantages of genetically modified crops?

* nutritional value improved
* can grow in arid conditions
* improve food supply
* longer shelf life
* reduce economic cost and carbon footprint

disadvantages of genetically modified crops?

* new traits could have unknow effects
* may limit local environments biodiversity
* GM crops may not be labelled

what is a clone?

group of genetically identical organisms or a group of cells derived from a single original parent cell

how are somatic cell nuclear transfers done?

1. somatic cells are removed from adult donor and cultured
2. unfertilised egg is removed from female adult and nucleus removed
3. enucleated egg cell is fused with nucleus from adult donor
4. electric current is delivered to stimulate egg to divide and develop into embryo
5. embryo is implanted into uterus of surrogate and clone of donor will develop

name some natural methods of animal cloning

fragmentation

budding

parthenogenesis

binary fission

what is fragmentation?

new organisms grow from a seperated fragment of te parent organism

what is parthenogenesis?

new organisms are gown from unfertilised ova

what is budding?

cells split off the parent organisms generating smaller daughter organism

what is binary fission?

parent organism divides producing 2 genetically identical daughter cells

plant cloning methods

vegetative propagation

spores

waht is vegetative progation?

small pieces can be introduce to grow independently

what are spores?

type of asexual reproduction

what are the two type of artificial cloning?

reproductive cloning and therapeutic cloning

what is reproductive cloning?

embryo is implanted into surrogate

what is therapeutic cloning?

embryonic cells can be induced to differentiate to create specific tissues or grans to transplant

what is stem cutting?

seperated portions of plant stem that can regrow into a clone by vegetative propagation