plant cloning

Question 1

what is biotechnology

Answer 1

the use of living organisms to provide a product or service to humans

Question 2

what is cloning?

Answer 2

making genetically identical copies or cells of whole organisms

Question 3

why is cloning an example of biotechnology?

Answer 3

the clones are used by humans for applications such as skin grafting

Question 4

describe sexual reproduction in plants

Answer 4

• 2 parent plants
• female gamete (ovum) in ovary of flower is fertilised by male gamete (pollen)
• product is seeds which are genetically different

Question 5

describe asexual reproduction in plants

Answer 5

• 1 parent
• produces genetically identical clones

Question 6

why is it useful for plants to be able to reproduce sexually and asexually?

Answer 6

• sexual increases genetic variation for natural selection
• asexual is rapid with good yield & reliably increases rare or endangered animals

Question 7

by what process does asexual reproduction occur?

Answer 7

vegetative propagation

Question 8

what is vegetative propagation?

Answer 8

growth of new plants from existing vegetative structures (non reproductive tissues eg roots/leaves)

Question 9

what do plants that undergo vegetative propagation produce?

Answer 9

structures containing meristem

Question 10

what grows from meristem

Answer 10

new, genetically identical plants

Question 11

what is meristematic tissue?

Answer 11

regions of plant cells capable of continuous division and growth

Question 12

what are perennating organs?

Answer 12

storage organs (e.g. tubers, rhizomes and corm), and buds

Question 13

what are perennating organs important for?

Answer 13

• enables plants to survive adverse conditions
• contain stored food from photosynthesis
• can remain dormant in soil

Question 14

summarise the steps in cauliflower plant cloning

Answer 14

• sterilise forceps
• clean work surface
• use scalpel to cut mini floret explants and place in petri dish
• place explants in SDICN to sterilise
• swirl every 2-3 mins for 15 mins
• use forceps to strain liquid from SDICN into a beaker
• transfer explant to agar gel
• press stalk into gel and incubate for 10 days

Question 15

describe how the steps used in cauliflower cloning prevent contamination

Answer 15

• sterilise work surface with ethanol
• use sterilised forceps to place explant in bleach
• pour bleach over forceps to sterilise again
• agar jelly contains bleach
• lids of culture bottle never put directly on work surface

Question 16

explain the purpose of sucrose in the agar gel

Answer 16

• provides respiratory substrate
• explant has no leaves for photosynthesis

Question 17

explain the purpose of murashige & skooge medium (minerals) in agar gel

Answer 17

• contains many minerals
• act as nitrogen source (ammonium nitrate)

Question 18

explain the purpose of agar in agar gel

Answer 18

• gelling agent
• holds substance together

Question 19

explain the purpose of SDICN in agar gel

Answer 19

• gentle bleach
• does not need to be rinsed

Question 20

why is it necessary to place explants in a well lit area?

Answer 20

• allows photosynthesis to occur when leaves grow
• glucose reserves are used up and the explant needs to meet nutritional needs through photosynthesis

Question 21

what are the advantages of using clones to cultivate new plants?

Answer 21

• many clones from one parent
• inexpensive on industrial scale
• multiple copies of endangered plants produced
• crop plants will be uniform in size / appearance

Question 22

what are the disadvantages of using cloning to cultivate new plants?

Answer 22

• disadvantageous traits from parent will be passed onto clones (eg. susceptibility to genetic disease)
• monoculture farming decreases biodiversity

Question 23

explain the purpose of kinetin in agar gel

Answer 23

• plant hormones that promote mitosis
• callus of totipotent cells can form

Question 24

what is a callus

Answer 24

proliferated cells that have formed a mass of identical cells