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Chapter 9: Cloning in Plants and
Animals Revision…read more

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Vegetative Propagation
· Asexual reproduction in plants
· No genetic variation is introduced into the population
· In nature, offspring inherit well-adapted genes, so have a good chance of
surviving in that habitat
· Plants remain close to parents, creating a dense population
Elm Trees
Reproduce by suckering ­ new trees grow from the
roots of the parent
Only mitosis, so the offspring are clones
All susceptible to Dutch Elm disease:
· Elm Bark Beetles make tunnels through wood
· Fungus grows in tunnels made by beetles
· Secretes enzymes that absorb nutrients and digest
wood. Produces spores on walls of the tunnel
· Beetle larvae fly to other elm trees with spores on
their backs. Other trees are contaminated.…read more

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Tissue Culture / Micropropagation
Growth of lots of clones of a plant artificially.
1. Select a plant with desirable characteristics.
2. Take a tiny amount of plant tissue from the meristem
3. Use asceptic technique
4. Put the plant tissue in agar ­ rich in nutrients. Eg. Glucose & cytokinines
5. A callus will form (a ball of undifferentiated cells). Stem cells in plants do
not terminally differentiate, so eg. Root cells can undifferentiate and then
differentiate to form leaf cells.
6. Divide the callus up to produce several new plants.
7. Change the medium to one containing Auxins, to encourage root and
shoot growth.
8. Transfer plantlets to sterile soil, providing it with warmth and light until it
is strong enough to survive on its own.…read more

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Callus ­ a bundle of undifferentiated plant cells that seals a wound on a plant and
provides a barrier against pathogens.
Meristematic cells ­ Plant cells that are dividing by mitosis. Found at growing tips.
Auxins and Cytokinins ­ Hormones that stimulate cell growth and division.
Explant ­ The group of cells removed from the parent plant in tissue culture.
Can reproduce plants Can breed for desirable
that are hard to grow characteristics
from seed eg. Orchids.
Why clone
Save species from
Provides large numbers
of particular crop variety
in a short space of time…read more

Slide 5

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Advantages and disadvantages of Natural Plant
Advantages Disadvantages
· Allows a particular plant to · All plants are genetically
colonise an area identical, so could all be killed
· Well-adapted plants are able to off by the same disease
reproduce to make more well- · Plants cannot colonise areas
adapted plants where it is not usually found,
whereas plants that reproduce
by seed dispersal can.
Strawberry Plants and Spider Plants ­ Put out runners. Runners find
new spaces of ground. Eventually, the connecting shoot is severed and
a new plant has been created…read more

Slide 6

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Animal Cloning
Replace loved pets
characteristics eg. To create
Why clone
Cows with a higher animals with
milk yield certain
conditions to test
drugs on
Prevent extinction
of an endangered
species…read more

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