OCR A A-Level Biology: 6.2.1 Cloning and Biotechnology 117 Quiz Questions Correctly
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OCR A A-Level Biology: Cloning and Biotechnology
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OCR A A-Level Biology: Cloning And Biotechnology
What are clones? - ️️Genetically identical copies of an organism
What is a clone? - ️️Genes, cells or whole organisms that carry identical genetic material because they are derived from the same original DNA
(Genetically identical organisms)
What are examples of clones? - ️️Identical...
OCR A A-Level Biology: 6.2.1 Cloning
and Biotechnology 117 Quiz Questions
Correctly
What are clones? - ✔ ✔ Genetically identical copies of an organism
What is a clone? - ✔ ✔ Genes, cells or whole organisms that carry identical genetic material because
they are derived from the same original DNA
(Genetically identical organisms)
What are examples of clones? - ✔ ✔ Identical twins (when zygote splits)
Plant producing runners (asexual reproduction)
Binary Fission in bacteria
Mitosis (cells)
What are the advantages of natural cloning? - ✔ ✔ - Quick - allows organisms to reproduce rapidly
and take advantages of resources
- All offspring have genetic information to enable them to survive in their environment
- Can be completed if sexual reproduction fails or is not possible
- Reproduction can happen with only one parent
What disadvantages of natural cloning? - ✔ ✔ - The offspring may be overcrowded
- No genetic diversity (except those caused by mutation during DNA replication)
- Population shows little variation between individuals
- Selection by environmental problems is not possible
- Detrimental changes in environment will affect all of the population
What is vegetative propagation? - ✔ ✔ Reproduction from vegetative parts of a plant - usually an
over-wintering organ
i.e.
generation of multiple offspring from one plant without sexual reproduction through the vegetative
parts of plant (non-reproductive)
,Describe the process of vegetative propagation - ✔ ✔ Many parts of plant contain cells that retain
ability to divide and differentiate
Means plants able to clone themselves
What are the different forms of vegetative propagation? - ✔ ✔ (1) Runners or stolens - horizontal
stems lying on ground that can form roots
(2) Rhizomes - horizontal underground stems lying on the ground that can form roots and shoots
(3) Suckers - new stems arising from roots of plants
(4) Bulbs - underground swollen stem with stored food and a bud
(5) Corms - underground stem with scaly leaves and buds
(6) Tubers - underground stem, e.g. potatoes
(7) Leaf margin - new leaves that bud off existing leaves
What are feature(s) of each form of vegetative propagation that allows them to form clones? - ✔ ✔
(1) are horizontal stems that can form roots at certain points on surface of ground
(2) same as (1) but underground - some adapted as thickened over-wintering organs from which new
stems will grow in spring
(3) in all cases, original horizontal branch may die, leaving new stem as separate individual
(4) over-wintering mechanism for many perennial monocotyledonous plants; grows series of fleshy leaf
bases; also apical buds that grows into new plants in spring
(5) solid; remain in ground over winter; in spring buds grow to produce 1+ new plants
(6) e.g. one potato will grow into 1+ plants, each new plant can then produce many new tubers
(7) clones on leaf margin drop off
What is vegetative production? - ✔ ✔ Refers to production of structures in an organism that can
grown into new individual organisms - resulting offsprings are clone of original parent plant
One method of artificial vegetative propagation is taking cutting, outline this process - ✔ ✔ (e.g.
leaf/root/scion cuttings)
A stem is cut between leaf joints (node) and placed in moist soil. May require rooting hormone to help it
establish new roots
One method of artificial vegetative propagation is tissue culture/ micropropagation, outline this process
- ✔ ✔ (a method of tissue culture techniques)
, Involves taking very small pieces of plant (explants) and using plant growth substances to encourage
them to grow into whole new plants
What is a tissue culture? - ✔ ✔ Growing new tissues, organs or plants from certain tissues cut from a
sample plant
When is micropropagation used? - ✔ ✔ - Plant is rare
- Plant doesn't respond well to natural cloning
- Doesn't readily make seeds
- Needs to be pathogen free
Outline the process of micropropagation - ✔ ✔ 1) Plant material selected and cut into small pieces -
aka explants - using plant growth substances to encourage it to grow and develop into whole new plants
2) Explants sterilised with dilute bleach or alcohol
3) Explants placed on sterile growth medium (usually agar gel) containing suitable nutrients, e.g.
glucose, amino acids and phosphates + high conc. of plant growth substances auxin + cytokinin -
stimulates cell of each explant to divide by mitosis to form callus
4) Callus then divided to produce larger no. of small clumps of undifferentiated cells
5) Callus then stimulated to grow, divide, differentiate into different plant tissues, achieved by growing
plants in different growth media containing different growth media
6) Once tiny plantlets have been formed, are transferred to greenhouse to be grown in compost or soil
and acclimatised to normal growing conditions
In the process of micropropagation - why are explants sterilised? - ✔ ✔ Essential to kill any bacteria
and fungi as would thrive in conditions supplied to help plant grow well
What is callus? - ✔ ✔ A mass of undifferentiated totipotent cells
How is callus stimulated to grow, divide, differentiate into different plant tissues? - ✔ ✔ Achieved by
growing plants in different growth media containing different growth media with different ratios of
auxin and cytokinin (e.g. 100 auxin:1 cytokinin stimulates root to form and 4:1 stimulates shoots to
form)
What are the arguments for micropropagation? - ✔ ✔ - allows for rapid production of large number
of plants with a known genetic makeup giving good yield
- produce viable number of plants after genetic modification of plant cells
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