6.4 Flashcards
What are clones?
Genetically identical organisms or cells
Advantages of natural cloning
- cloning is relatively rapid so population can increase fairly quickly
- reproduction can be carried out even if there is only one parent, where sexual reproduction can’t happen
Disadvantages of natural cloning
- offspring may become overcrowded
- There will be no genetic diversity (apart from that caused by mutations in DNA replication)
- the population shows little variation
- an environmental change means the whole population is affected
What is vegetative propagation
plant clones being created from vegetative parts of a plant
what are 4 kinds of stems plants can produce clones
- Runners
- Stolons
- rhizomes
- suckers
what are runners and stolons
horizontal stems that grow on the surface of the ground that will produce a clone
What are rhizomes
horizontal stems the grow beneath the ground
what are suckers
new stems that grow from the
what are bulbs
fleshy underground stem from which grow leaves and they also have an apical bud that allows flowers to grow in spring
What are corms
similar to bulb but solid not fleshy
What plant reproduces asexually from its leaves
the kalanchoe
when does cloning happen in animals
when the zygote splits to become two separate cells resulting in twins
what are 3 ways of artificially cloning plants
cuttings
tissue culture
micropropagation
how do clone a plant through cuttings
to make a cutting, a stem is cut between two leafy joints (nodes) and may be dipped in rooting hormone and then is put in moist soil.
May also be useful to remove the bark from the end of the stem so pant produces a callus.
what other parts of the plant can cuttings be made
- root cuttings, where a section of the root is buried below the soil surface and so it produces new shoots
- scion cuttings, which are dormant woody twigs
- leaf cuttings, where a leaf is placed in the soil and it produces new stems
what is tissue culture
is a series of techniques used to grow plants from samples in a nutrient medium on sterile conditions
what is micropropagation
growing large numbers of new plants from meristem tissue taken from a sample plant
what are the steps of microporopagation
- meristem tissue taken, these are called explants
- explants are steralised using alcohol
- explants placed on sterile growth medium contains hormones
- a callus forms and it is divided into a large number of small clumps of undifferentitated cells
- small clumps of cells moved to different growth medium and small plantlets are formed
advantages of artificial cloning
- cloning is faster than growing from seeds
- cloning can happen where sexual reproduction can’t
- means plants are genetical identical so show desirable charictaristics
- all plants grown are uniform so easier to harvest
- using meristem as an explant ensures new plants are free from viruses
disadvantages of artificial cloning
- tissue culture is labour intensive
- expensive
- no genetic variation
what are totipotent cells
the can differentitate into any cells
what is embryo twinning/ splitting
splitting an embryo to create two genetically identical embryos
steps of embryo twinning/ splitting
- a zygote is created in IVF
- zygote is allowed to divide by mitosis to form a small ball of cells
- cells are seperated and allowed to continue dividing
- each small mass of cells is placed into the uterus of a surrogate mother
steps of somatic nuclear cell transfer
- an egg cell is obtained and its nucleus is removed
- a body cell of the adult to be cloned is obtained(called somatic cell)
- the somatic cell is fused with the egg cell by an electric shock
- electric shock also causes cell to start developing as if it had been fertilised
- cell undergoes mitosis
- embryo is placed in surragote mother
what is therapeutic cloning
new tissue and organs that can be grown as replacement parts for people who are not well
arguments for artificial cloning
- can produce a whole herd of animals with high yeild
- testing medical drugs on cloned cells and tissues avoids using them on animals or people for testing
- individuals form an endangered species can be cloned to increase numbers
arguments against artificial cloning
-cloned animals may be less healthy
-very expensive for a low success rate
advantages of using microorganisms in biotechnology
- cheap
- easy to grow
- reproduce quickly
- can be fed by-products from other food industires
- production can take place anywhere as not dependent on climate
- fewer ethical issues
how is biotechnology used in production of yogurt
fermented milk
bacteria convert lactose to lactic acid
the acidity denatures proteins causing coagulation
how is biotechnology used in the production of cheese
- bacteria converts lactose to lactic acid
- acidified milk is mixed with rennin
- rennin coagulates casein in presence of calcium ions
- curd forms that is pressed into moulds
how is biotechnology used in baking
- ingredients are mixed together to form dough
- the yeast in the dough respires anaerobically producing carbon dioxide bubbles causing dough to rise
- the dough is baked and any alcohol evaporates
how is biotechnology used in the production of alcoholic bevrages
wine
-yeast on surface of grapes respires anaerobically using sugar in crushed grapes
beer
-malting grains convert starch to maltose which is respired by yeast.