6.2.1 - Cloning and Biotechnology Flashcards
What is a clone?
a genetically identical organism
-produced by asexual reproduction
What is vegetative propogation?
asexual reproduction in plants where a structure (eg. stem, root, leaf, bud) which can differentiate into a fully grown plant
-produces a clone
Name some examples of natural vegetative propagation
- using rhizomes (eg. bamboo, raspberries, nettles, etc)
- using runners (eg. strawberries, spider plants, etc)
- using suckers (eg. elm trees)
- using tubers (eg. potatoes)
- using bulbs (eg. daffodils, tulips, etc)
How do plants undergo vegetative propagation using rhizomes?
a rhizome is a stem-like structure that grow horizontally underground from the plant, which produces nodes that shoots and roots can develop from
eg. bamboo, raspberries, nettles
How do plants undergo vegetative propagation using runners?
runners are stem-like structures that grow horizontally above ground from the plant, which produces nodes that shoots and roots can develop from when the nodes are in contact with the ground
eg. strawberries, spider plants, etc
How do plants undergo vegetative propagation using suckers?
suckers are shoots that grow from sucker bulbs (undeveloped shoots)
eg. elm trees
How do plants undergo vegetative propagation using tubers?
tubers are swollen underground food stores attached to plant’s stem which has eyes that new plants can sprout from
eg. potatoes
How do plants undergo vegetative propagation using bulbs?
bulbs are swollen leaf bases that acts as food stores
new bulbs can develop from a bulb and grow to form new plants
eg. daffodils, tulips, etc
How can plant cuttings be used to clone plants?
- a section of stem is cut from the plant
- cutting is placed in rooting powder (containing plant hormones like auxins and cytokines which stimulate root growth)
- cutting is planted into a pot containing compost/growth medium
- when the cutting has developed roots, it can be planted into soil
What is grafting?
when a plant shoot is placed into a slit in the base of another plant (a graft) so that their tissues grow together to produce a plant with both plants characteristics
- base is chosen for its characteristics (eg. tall/short plant) which are required for the shoot
eg. used with fruit plants
What is micropropagation?
the process of making large numbers of cloned (genetically identical) plants from a single parent plant using tissue culture
What happens in tissue culture?
- tissue samples (containing many cells) are taken from the plant
- tissue samples are transferred to a sterile agar plate
- plant hormones are added to the agar plates (to stimulate cells to divide)
- each group of cells divides to form a callus
- each callus is separated into a number of groups of cells so more clone plants can be produced
- plantlets are produced and transferred to pots containing soil and are grown around 20°C for maximum growth
- lots of clone plants are produced
When is tissue cultured/micropropagation used?
- to clone endangered/rare plants (conservation)
- to grow genetically engineered plants
- to grow plants that don’t readily reproduce
- to grow pathogen-free plants (eg. strawberries, bananas, potatoes)
- to produce plants which produce medicines
- for agriculture and horticulture
- for commercial uses (to produce orchids, grapes, sugar cane, potatoes, bananas, strawberries, etc)
What are the arguments for artificial plant cloning?
- lots of plants are produced quickly (quicker than growing from seed)
- desired characteristics are always passed on
- tissue culture allows plants to be reproduced in any season (environment is controlled)
- less space required for tissue culture
- infertile plants can be grown
- plants producing seedless fruits can be grown
- disease-free plants can be grown
What are the arguments against artificial plant cloning?
- plants produced are all genetically identical so are susceptible to disease and climate change
- expensive (high energy use)
- requires skilled workers
- explants are susceptible to contamination (need sterile conditions)
- large numbers can be lost in the process
How are clones produced naturally in animals?
embryo splits to produce identical twins
Excluding twins, how can animals naturally produce clones of themselves?
- by fragmentation -in star fish
- by binary fission -in flatworms
- by budding -in hydra
these are all invertebrates so not too complex to clone
How can animal clones be artificially produced?
- artificial embryo twinning
- somatic cell nuclear transfer (SCNT)
How are clones produced artificially using artificial embryo twinning?
- embryo is produced by IVF (egg cell is extracted from a female and fertilised in a petri dish and left to divide to form an embryo) or artificial insemination (animal is given hormones to super ovulate and sperm is added so that egg is fertilised, which is then removed from the uterus)
- embryo cells are separated (around day 6) and then grown to produce multiple embryos
- embryos are implanted into surrogate mothers
- embryos develop in surrogate mothers and clones are born
Why are embryos implanted into different surrogate mothers during artificial cloning?
single pregnancies have fewer risks
What does SCNT stand for?
somatic cell nuclear transfer
How are clones produced artificially using somatic cell nuclear transfer (SCNT)?
- a nucleus is separated from a somatic cell of the donor
- an egg cell is taken from another animal and its nucleus is removed (the cell is enucleated)
- the nucleus from the donor is fused with the enucleated egg cell using an electric shock
- the fused cell divides and forms an embryo
- the embryo is transferred to a surrogate mother and develops and a clone is born
Why is somatic cell nuclear transfer classed as asexual reprouction?
there is no fertilisation involved
Why are different breeds of sheep used for the egg cell in somatic cell nuclear transfer?
to prove cloning was successful and that the clone has genetic material of the other sheep
Why does the cloned animal produced by somatic cell nuclear transfer not have the exact same genetic material as the donor?
the cloned animal’s mitochondrial DNA comes from the egg cell
What are the arguments for artificial animal cloning?
- desired characteristics are always passed on
- infertile animals can be reproduced
- SCNT can be used to clone specific animals, such as rare/endangered animals, pets, high value animals, etc
- artificial twinning enables production of many high yielding animals
- in SCNT, genetically modified animals can be cloned
What are the arguments against artificial animal cloning?
- SCNT is an inefficient process (rare to produce a viable clone + many embryos fail to survive)
- no genetic diversity so are susceptible to disease and climate change
- clones might not live as long as natural offspring
- people disagree with genetically modified animals, particularly as food sources
What is biotechnology?
the industrial use of living organisms (or parts of living organisms) to produce food, drugs or other products for human use
-usually using microorganisms
Why are microorganisms used in biotechnological processes?
- short life cycle (grow rapidly)
- easy to create their ideal growth conditions (nutrients, temp, pH, moisture levels, etc)
- economical to use because they can be grown on a range of cheap materials
- can be grown at any time of year
Name some examples of biotechnological processes which use microorganisms
- brewing
- baking
- cheese making
- yogurt production
- penicillin production
- insulin production
- bioremediation
What microorganism is involved in brewing?
yeast
What are the steps in brewing?
- malting: barley germinates, which produces enzymes that break starch into sugars and malt is produced
- mashing: malt is mixed with hot water and enzymes break malt into wort (which is sterilised and cooled)
- fermentation: yeast uses wort for anaerobic respiration and produces ethanol
What microorganism is involved in baking?
yeast
What are the steps in baking?
- active yeast is added to ingredients and is mixed and left in a warm environment to rise (yeast produces CO2, which causes the bread to rise)
- dough is kneaded
- dough is cooked in hot oven (more CO2 produced causes it to rise more)
What microorganism is involved in cheese making?
bacteria chymosin enzyme (in rennet)