6.2.1 Biotechnology and cloning Flashcards
What is a clone?
A genetically identical copy.
What are some examples of cloning?
Binary fission.
Mitosis.
Budding.
What are the advantages of natural cloning?
Conditions that are good for the parent will be good for the offspring.
It can happen rapidly, no need to find a mate.
Reproduction can happen with one parent when sexual reproduction isn’t possible.
What are the disadvantages of natural cloning?
Vulnerability to changes in environment.
Overcrowding.
No genetic diversity (unless mutation).
Little variation.
Selection not possible.
What is vegetative propogation?
Plants form natural clones through vegetative propagation. They are produced via mitosis from undifferentiated meristem cells. Depending on the species it can be initiated from the roots, shoots and leaves.
What are the 7 types of vegetative propagation?
Runners.
Rhizomes.
Root suckers.
Bulbs.
Corms.
Tubers.
Leaves,
What is the difference between a runner and a rhizome?
Runners are above ground, rhizomes below.
What is a runner?
Eg spider plants or strawberry bushes. The runner forms from the stem and then shoots and roots then form away from the parent plant.
What is a rhizome?
Runners that are under the ground.
What is a sucker / basal sprout?
New stems that grow from the roots of the plant. The horizontal section dies off and the new plant remains, the sucker.
What is a bulb?
Overwintering mechanism (perennating organ) for many perennial monocotyledonous plants.
The perennating organ contains stored food from photosynthesis. They allow plants to survive adverse conditions and then produce a new shoot using energy from the food source. The new plants are clones to the parent plants. Genetically identical.
What is a corm?
Solid rather than fleshy like bulb. Underground stem with scaly leaves and buds. Croci and gladioli.
How do leaves produce clones?
Clones grow on leaf margins. They drop off and take root.
What are tubers and how do they produce clones?
New plants will grow out of swollen, modified roots called tubers. Buds develop. Eg potato.
What is the easiest way to make a clone of a plant?
Cuttings
What is the full process of taking a cutting?
Use a shoot from a healthy plant (with no flowers)
Cut the stem between nodes at a slant.
Dip in rooting powder with auxin.
Place in soil and add water.
Place in propagation box.
To reduce transpiration cover with a plastic bag.
New roots grow from tissues in the stem.
Why is taking cuttings not always the best method?
Time-consuming on a large scale, so can’t be used.
Lots of space required.
Some plants do not grow well by this method.
How can you create clones from bulbs?
Bulbs can be split and planted separately.
How can you create natural clones by runners?
Young shoots from runners can be taken and planted separately.
What are the agricultural advantages of vegetative propagation?
Some crops cannot reproduce sexually (if they’re seedless).
Young seedlings are less likely to survive than cloned plants.
Quicker than growing from a seed.
Known outcome- their shape/size/quality/yield is predictable.
It can be done at any time of year regardless of season.
What is the definition of micropropagation?
It is the production of a large number of plants from a small piece of plant material (produced via tissue culture).
When is micropropagation used?
When the desirable plant;
-Doesn’t produce many seeds,
-Doesn’t respond well to natural cloning.
-Is GM or selectively bred.
-Needs to be pathogen free
What is the process of micropropagation?
Cells are taken from the shoot tip or axial/axillary bud (in the leaf). These cells are called the explant.
Cells are sterilised with ethanol before being placed onto nutrient medium.
Explants placed on sterile nutrient/growth medium (contains glucose, phosphates, amino acids, hormones).
Hormones stimulate mitosis which causes a callus culture (ball of undifferentiated cells) to form.
This is divided to produce lots of small clumps of undifferentiated cells.
Transferred to a new agar medium - root growth hormone. Then shoot growth hormone.
Plantlets grow and are transferred into compost.
