biotechnology Flashcards
define clone
offspring produced by mitosis - genetically identical to parent organism
define asexual reproduction
generation of new individuals (mitosis) to make clones
define reproductive cloning
using artificial cloning to produce 2 or more individuals that are clones
define vegetative propagation
production of plant clones from non-reproductive tissues
define perennating organ
structures in plants that allow them to survive extreme conditions.
- contain stored food
- remain dormant in soil
describe the link between perennating organs and vegetative propagation
vegetative propagation takes place from perennating organs after adverse conditions.
When stores of food are used to grow new plants from the organ
what are the 4 ways in which plants naturally clone
- rhizomes
- stolons
- tubers
- bulbs
what are rhizomes
horizontal underground stems
what are stolons
horizontal above ground stems
what are tubers
swollen underground stems
what are bulbs
swollen, tightly packed, underground leaves
define horticulture
the branch of agriculture that deals with just plants
define agriculture
the cultivation and breeding of animals, plant, fungi or food or other resources
How is the production of natural clones exploited in horticulture
create new plants by:
- splitting up bulbs
- removing young plants from runners
- cutting up rhizomes
increases plant numbers cheaply and all have same genetics as parents
define taking cuttings
removing and planting short sections of stem of a plant in order to produce clones
how is taking cuttings used in horticulture
used to increase plant numbers (quicker than seed growing).
all are clones of parents - good stock
6 ways in which the success rate of taking cuttings can be increased
- use a non-flowering stem
- make oblique cut in the stem
- use hormone rooting powder
- reduce leaves to two or four
- keep cutting well watered
- cover the cutting with a plastic bag for a few days
how does using a non flowering stem increase success rate of taking cuttings
resources in plant aren’t needed to maintain cells of flowers so can be used to grow roots instead
how does making oblique cuts in the stem increase success rate of taking cuttings
larger surface area for roots to grow from
how does using hormone rooting powder increase success rate of taking cuttings
encourages the growth of new roots
how does reducing leaves to two or four increase success rate of taking cuttings
reduces transpiration rate as water uptake is low until new roots are developed
how does keeping cutting well watered increase success rate of taking cuttings
will die if not enough water and needs to establish roots to draw up enough water itself
how does covering the cutting with a plastic bag increase success rate of taking cuttings
reduces the loss of water through transpiration while new roots establish
5 examples of crops that are propagated by cloning
sugar cane, bananas, sweet potatoes, cassava, tea and coffee
advantages of propagating crops by cloning
large numbers of new plants (especially sterile plants such as seedless grapes)
reliable increasing numbers of rare plants / plants difficult to grow
known genetic profile - produce good quality crops every time
uniform plants - easy harvesting
disadvantages of propagating crops by cloning
produces a monoculture - all plants are susceptible to the same diseases or changes in environment.
labour intensive
pathogens can be passed from parents
advantages of production of individuals by seed
genetically diverse
low cost
favoured when low cosr and genetic variety is important
occurs naturally - no need for human intervention
disadvantages of production of individuals by seed
long growing time
need to maximise pollination
provide ideal requirements for germination
problems when plants difficult to grow from seed
when sexual reproduction is unreliable
dependent on seasons
advantages of taking cuttings
clones of parents
short growing time
favoured when need good crop quickly / when clones are wanted
guaranteed quality
disadvantages of taking cuttings
high cost
labour intensive
need to use non flowering stems and rooting hormone
plenty of watering
problems occur when susceptible to drying out and pathogens can be transferred
monoculture is a problem
define tissue culture
the method of growing plant cells in isolation from the parent plant in sterile conditions on a nutrient culture medium
define micropropagation
the process of making large numbers of genetically identical offspring from a single parent using tissue culture
define explant
the material removed from a parent plant for tissue culture
define callus
a mass of undifferentiated plant cells that have grown from an explant
why might micropropagation be used to clone plants
the desirable plant does not readily produce seeds
desirable plant doesn’t respond well to natural cloning
desirable plant is very rare
desirable plant has been genetically modified or selectively bred with difficulty
desired plant is required to be pathogen free
describe the process of micropropagation by callus tissue culture
- take a small sample of tissue from plant (meristem tissue from shoot tips) (sterile conditions to avoid contamination)
- explant is sterilised
- place in sterile culture medium containing plant hormones, cells proliferate by mitosis forming a mass of cells known as a callus
- callus divided and individual cells transferred to a new medium
- potted into compost to become small plants
9 examples of plants produces by micropropagation
potatoes, sugar cane, bananas, cassava, strawberries, grapes, chrysanthemums, douglas firs, orchids
aruguments for micropropagation
can grow plants that are naturally infertile
genetically modified for consumer tastes
known genetic profile
uniform crop
disease free
any season as tissue culture carried out indoors
arguments against micropropgation
conditions must be kept sterile - aseptic conditions
any infected cultures must be disposed of
expensive
if source material infected with virus, clones will be too.
large numbers of plants can be lost in the process
produces monoculture
labout intensive
explants and plantlets vulnerable to infection
what is mitotic parthenogenesis
development of an embryo from an unfertilised egg formed by mitosis rather than meiosis so has full number of chromosomes
how can animal damage lead to natural cloning
multiple pieces develop into new organisms
what is monozygotic twinning
one zygote splits and forms 2 embryos
what is budding
new organism develops from an outgrowth (bud) due to cell divison at a particular site.
what is fragmentation
when organism is split into fragments which each develop into mature, fully grown individuals
how can offspring be produces without a mate, but are not clones
parthenogenesis in which an egg is fertilised by another egg that are both from the mother. Different alleles/random assortment result in non-clones.
define monozygotic
monozygotic twins are formed from a single fertilised egg
describe how identical twins occur
It occurs when one egg is fertilised by one sperm and one zygote forms.
the early embryo splits in two and each half grows into a new individual.
state the two ways of artificially cloning animals
embryo splitting
somatic cell nuclear transfer
describe how animals are clones by splitting embryos
- gametes fuse forming zygote
- embryo develops to 16-cell stage
- embryo is separated to individual cells
- each cell now develops further into a separate and identical embryo
- surrogate mothers have uterus made ready by hormonal treatment
- each embryo is implanted into a surrogate mother
- surrogate mother carry clone to term. identical cloned offspring born
