Module 6: Cloning And Biotechnology Flashcards
What is a clone
a genetically identical organism or cell
What is natrual plant cloning known from non reproudcive tissues known as
vegatative propogation
What are the different types of ways that plants can natrually clone themselves
Rhizomes: stem structures that grow horizontally underground, away from parent plant. These have nodes where new shoots can develop
Stolons: also known as runners, grow above ground. These have nodes where new shoots can develop (examples inculde strawberries)
Suckers: shoots that grow from sucker buds, present in roots of parent plant. An example of this is a elm tree
Tubers: large underground plant structures that act as food store, covered in eyes and each eye can sprout to form a new plant (example is potatoes)
Bulbs: underground food stores, new bulbs can develop from orginal bulbs to form individual plants
How can vegetative propgation be used in horticulture or agriculture
- Can take cuttings
- Use grafting: when you join shoot from one plant to the growing stem of another plant
- Layering: when you bend a stem downwards, so it enters the soil and grows a new plant
Why do plants do vegetative propogation
- only need one parent so its faster
- all are genetically identical, no genetic variation so if conditions are favourable then its good, as they can survive and reporduce
- downside is if conditions change then they may die
How can we produce clones from cuttings
- use a scalpel from stem at 45 degrees
- remove leaves leaving just one at the tip
- Dip lower end of cutting in rooting powder
- Place cutting in plant with suitible growth meidum
- Place pot in a warm and suitlbe condition (moist soil, humid air which reduces transpiration stress), can cover pot with plastic bag to achieve this
- When cutting forms its own roots can plant elsewhere so it can grow
Where else can you take cuttings of a plant apart from the stem
- Root cutting, use kind of the same method, dip in rooting powder and place in suitble growth medium
- Leaf-cutting (split vein cutting): when you remove a complete leaf and large veins on lower leaf using a scalpel, then place on growth medium, with broken veins facing down
How is tissue culture carried out
- Cells from orginal plant taken from root and stem (where the meristem is)
- Cells steralised using bleach ethanol to kill any micro-organisims (bacteria and fungi will compete from nutrients decreasing growth rate)
- Explant placed in medium containing amino acids, glucose and high conc of plant horomones . Carried out in aspectic conditions, and cells proudce mass of cells called a callus
- Callus is divided up and placed in new medium contaiing nutrients and hormones, this stimulates development of plantlets
- Young planlets are taken out to grow
What is micro-propogation
- when tissue culture is used to produce many plants quickly
- cells are taken and subcultured and this is repeated several times
What are the arguments for and against artifical plant cloning
advantages
1 quick ;
2 disease-free / virus-free , stock created ;
3 plants have same feature / uniform plants created ;
4 can reproduce infertile plants ;
5 can reproduce plants that are hard to grow from seed ;
6 create whole plants from GM cells ;
7 production , not determined by seasons /
at any time / anywhere in the world ;
8 (plantlets small) can be transported easily /
grown in small space ;
9 can save rare species from extinction ;
disadvantages
Against
10 expensive / labour intensive , process ;
11 process can fail due to microbial contamination ;
12 all offspring susceptible to same ,
pest / disease /
named environmental factor (e.g. drought) ;
13 no / low / little , genetic variation ;
Give an example of a natrual clone in vertbrates
Monozygotic twins
Explain the process of artifical embryo twinning
- Egg cell with desirable traits is extracted from animal and is fertilised with sperm with desirable characteristics in a petri dish
- Fertilised egg is left to divide forming an embryo in vitro
- individual cells from embryo are separated and placed in separate Petri dishes, allows more embryos to form
- implanted in female animal
- embryos develop in surrogates and when offspring are born all of them are genetically identical
Give examples of natrual cloning in invertibrates
Hydra: produce buds on side of the body which can form into new hydra
Starfish: can generate entire starfish from fragments of their body
Explain the process of somatic cell nuclear transfer (SCNT)
- A somatic cell is taken from sheep A (or animal A) and the nucleus is extracted
- An oocyte (unnucleated egg cell) is taken from sheep B or animal B, its nucleus is removed to form an enucleated oocyte
- Nucleus from sheep A is inserted into an enucleated oocyte from sheep B
- Nucleus and enucleated oocyte are fused together using an electric shock and stimulated to divide by electrofusion, this produces an embryo
- Embryo is implanted into a surrogate mother and a lamb is born and is a clone of sheep A
Why is the clone made in somatic cell transfer not fully identical
In enucleated egg cell there is still mitochondrial DNA
What are the uses of animal cloning
- Can be used for research purposes, for example, can test drugs on cloned animals, as they are all genetically identical, genetic differences are removed
- Therapeutic cloning: clone yourself, obtain stem cell, and this means that you won’t reject your own cells (NOT allowed though)
- Used in agriculture so farmers can increase the number of animals with desirable characteristics to breed from
- Some animals have been modified to produce a useful substance (for example a goat has been genetically modified to produce a beneficial protein in milk could be cloned
- cloning can be used to save endangered animals from extinction
What are the arguments for and against animal cloning
for
- Desirable genetic characteristics are always passed onto clones
- Animals can be cloned any seasons, so you wouldn’t need to wait for breeding seasons
- can help us develop new treatments for disease
- provides a way of growing infertile animals
- can increase the number of rare animals and endangered populations which helps preserve biodiversity
Against
- Undesirable characteristics can be passed onto clones
- no genetic variability so a single disease could kill all of them
- production of clones is time-consuming and expensive
- un ethical as clones may not live as long
- using cloned human embryos as a source of stem cells is controversial some people say ts destroying human life
What is meant by the term biotechnology
use living organisms (yeast or bacteria) or parts of living organisms (enzymes) to produce food, drugs or other products
Why do we use living organisms and parts of living organisms in industrial processes
- can be grown any time of year
- they are cheap
- due to their short life cycle, they grow rapidly
- ideal growth conditions (pH, o2 levels etc) can be easily created
- can genetically engineer them to carry out reactions they wouldn’t normally do
- no welfare or ethical conditions issues to consider
- products easy to isolate
How is biotechnology used to make bread
- Yeast respires aerobically, so the Co2 it produces is used to make bread used
- the yeast usually used is called Saccharomyces cerevisiae
Commerial process
- active yeast is added to flour and is left in warm environment to prove
- Dough is knocked back, kneaded and allowed to rise again
- cooked in hot oven so co2 bubbles expand, causing it to rise further
How is biotechnology used to make beer
In beer, yeast respires anaerobically
-this produces ethanol
Commercial process
-Malting: barley germinates, enzymes are produced that break starch into sugars for yeast to respire
-Mashing: malt mixed with hot water, enzymes break down starch producing wort;
Fermentation happens
Beer is conditioned for 4-29 days
Beer is then filtered and pasteurised
How is biotechnology used to make cheese
Cheese making invoices lactic acid bacteria
-converts lactose in milk into lactic acid which makes it turn sour and contributes to it solidifying
Commerical process
Milk pasteurised - heated to 95°C for 20 seconds to kill off natural bacteria
Milk is homogenised – fat droplets evenly distributed
Bacteria and chymosin enzyme are added
-Originally we use to use rennet which contains chymosin from the lining of calves stomach but now yeast have been genetically modified to produce the enzyme
Milk separates into solid curds and liquid whey (coagulation)
How is biotechnology used to make yoghurt
Involves use of lactic acid bacteria to clot the milk and cause it to thicken
Commercial process
- milk pasteurised by heating
- Add bacteria culture and incubate (Lactobacillus)
- Sample it
- Then you can add flavours, colours
How is biotechnology used to make food (single cell protein)
- Micro-organims can be used to proudce proteins for human consumption
- Mycoprotein is used in quorn
- the fungus used to proudce the protein is called Fusarium venetanumn
How does it work
- single celled fungus grown in large fermenters using glucose syrup as food
- then itrs combined with albumen
- compressed and formed into meat subsituates