OCR A Level Biology: Cloning and
Biotechnology Exam Question And
Answer
What are natural clones used for? - Horticulture
Examples of natural plant clones - Bulbs, runners, rhizomes, stem tubers
Other phrase for natural cloning - Vegetative propagation
How bulbs do natural cloning - Leaf base swells with stored food, buds form internally,
develop into new shoots and plants in the next season
How runners do natural cloning - Lateral stem grows away from the parent plant, roots
develop where the runner touches the ground, new plant develops, runner withers away
How rhizomes do natural cloning - Specialised horizontal stem swollen with food
running underground, buds develop, form new vertical shoots, become plants
How stem tubers do natural cloning - Tip of underground stem becomes swollen with
stored food, forms tuber, buds on tuber produce new shoots
How are natural clones used in horticulture? - Splitting of bulbs, removing young plants
from runners, cutting up rhizomes, all increase plant numbers cheaply
How to take a plant cutting - Select a non-flowering stem, angled cut across the stem
below a node, reduce the leaves, dip in rooting powder, put in watered soil, cover with a
plastic bag for a few days, water
Example of a simple cloning technique - Cuttings
Way of making artificial clones - Tissue culture
Process of tissue culture - Small samples of meristematic tissue tissue taken from virus
free plant from shoot tips or axial buds, sterile conditions, sterilised in bleach or sodium
dichloroisocyanurate, removed material now an explant, explant placed on sterile
culture medium, callus forms, callus divided into smaller clumps of cells, placed on new
culture medium, platelets grow, placed in compost
What's in the sterile nutrient medium for tissue culture? - Auxins, cytokinins, glucose,
amino acids
Callus - Group of undifferentiated genetically identical cells
, Difference between micropropagation and tissue culture - Micropropagation is a type of
tissue culture
Advantages of artificial plant cloning - Can grow plants which have low levels of fertility,
large number of plants with a known genetic code produced rapidly, can grow rare or
endangered plant species, can produce large numbers of seedless plants, disease free
plants because meristem is used
Disadvantages of artificial plant cloning - Skilled workers required, have to make sure
tissue isn't infected with a virus, infection possible during production, all plants at risk
when environment changes or when exposed to a disease, limits evolution, large
numbers of plants lost during production
Example of use of plant cloning in horticulture and agriculture - Sugar cane
How is sugar cane cloned? - Short lengths of cane with three nodes are cut, buried in
clear field in shallow trenches, covered with thin layer of soil
Examples of natural animal clones - Starfish, flatworms, sponges, Hydra, monozygotic
twins
How are starfish natural animal clones? - Entire animals can be regenerated from
fragments of the original
How are flatworms and sponges natural animal clones? - Fragment and form identical
animals as part of the natural reproductive cycle
How are Hydra natural animal clones - Produce buds on the side of the body, develop
into genetically identical clones
Process by which monozygotic twins occur - Embryo splitting
How can artificial clones in animals be made? - Artificial embryo twinning, somatic cell
nuclear transfer
How does artificial embryo twinning occur? - Cow treated with hormones so she super-
ovulates, ova fertilised naturally or by artificial insemination, early embryos gently
flushed out of the uterus, at day six the early embryo is split into smaller embryos, split
embryos grown in lab for a few days, implanted into a surrogate mother
Process of somatic cell nuclear transfer - Nucleus removed from somatic cell of an adult
animal, mature ovum enucleated, nucleus from somatic cell put into enucleated ovum,
given a mild electric sock to get it to divide, embryo that develops is transferred into the
uterus of a surrogate mother
Biotechnology Exam Question And
Answer
What are natural clones used for? - Horticulture
Examples of natural plant clones - Bulbs, runners, rhizomes, stem tubers
Other phrase for natural cloning - Vegetative propagation
How bulbs do natural cloning - Leaf base swells with stored food, buds form internally,
develop into new shoots and plants in the next season
How runners do natural cloning - Lateral stem grows away from the parent plant, roots
develop where the runner touches the ground, new plant develops, runner withers away
How rhizomes do natural cloning - Specialised horizontal stem swollen with food
running underground, buds develop, form new vertical shoots, become plants
How stem tubers do natural cloning - Tip of underground stem becomes swollen with
stored food, forms tuber, buds on tuber produce new shoots
How are natural clones used in horticulture? - Splitting of bulbs, removing young plants
from runners, cutting up rhizomes, all increase plant numbers cheaply
How to take a plant cutting - Select a non-flowering stem, angled cut across the stem
below a node, reduce the leaves, dip in rooting powder, put in watered soil, cover with a
plastic bag for a few days, water
Example of a simple cloning technique - Cuttings
Way of making artificial clones - Tissue culture
Process of tissue culture - Small samples of meristematic tissue tissue taken from virus
free plant from shoot tips or axial buds, sterile conditions, sterilised in bleach or sodium
dichloroisocyanurate, removed material now an explant, explant placed on sterile
culture medium, callus forms, callus divided into smaller clumps of cells, placed on new
culture medium, platelets grow, placed in compost
What's in the sterile nutrient medium for tissue culture? - Auxins, cytokinins, glucose,
amino acids
Callus - Group of undifferentiated genetically identical cells
, Difference between micropropagation and tissue culture - Micropropagation is a type of
tissue culture
Advantages of artificial plant cloning - Can grow plants which have low levels of fertility,
large number of plants with a known genetic code produced rapidly, can grow rare or
endangered plant species, can produce large numbers of seedless plants, disease free
plants because meristem is used
Disadvantages of artificial plant cloning - Skilled workers required, have to make sure
tissue isn't infected with a virus, infection possible during production, all plants at risk
when environment changes or when exposed to a disease, limits evolution, large
numbers of plants lost during production
Example of use of plant cloning in horticulture and agriculture - Sugar cane
How is sugar cane cloned? - Short lengths of cane with three nodes are cut, buried in
clear field in shallow trenches, covered with thin layer of soil
Examples of natural animal clones - Starfish, flatworms, sponges, Hydra, monozygotic
twins
How are starfish natural animal clones? - Entire animals can be regenerated from
fragments of the original
How are flatworms and sponges natural animal clones? - Fragment and form identical
animals as part of the natural reproductive cycle
How are Hydra natural animal clones - Produce buds on the side of the body, develop
into genetically identical clones
Process by which monozygotic twins occur - Embryo splitting
How can artificial clones in animals be made? - Artificial embryo twinning, somatic cell
nuclear transfer
How does artificial embryo twinning occur? - Cow treated with hormones so she super-
ovulates, ova fertilised naturally or by artificial insemination, early embryos gently
flushed out of the uterus, at day six the early embryo is split into smaller embryos, split
embryos grown in lab for a few days, implanted into a surrogate mother
Process of somatic cell nuclear transfer - Nucleus removed from somatic cell of an adult
animal, mature ovum enucleated, nucleus from somatic cell put into enucleated ovum,
given a mild electric sock to get it to divide, embryo that develops is transferred into the
uterus of a surrogate mother
