Cloning and Biotech Flashcards
1
Q
two types of cloning
A
- natural
- artificial
2
Q
name for natural cloning in plants
A
vegetative propagation
3
Q
perennating organs
A
organs which store food from photosynthesis and can remain dormant in the soil
4
Q
purpose of perennating organs
A
- asexual reproduction
- survival between growing seasons
5
Q
reproductive vs non-reproductive cloning
A
- reproductive produces a whole organism
- non-reproductive producer cells or tissues
6
Q
examples of reproductive cloning
A
- asexual reproduction in plants
- artificial propagation in plants
- artificial embryos splitting
- somatic cell nuclear transfer
7
Q
applications of non-reproductive cleaning
A
- treating genetic disorders
- treating degenerative conditions
- treating damaged caused by trauma
8
Q
types of natural plant clones
A
- bulbs
- runners
- rhizomes
- stem tubers
9
Q
examples of bulbs
A
- daffodils
- onions
- shallots
- crocus
10
Q
bulbs
A
- leaf bases swell with stored food from photosynthesis
- buds form internally which develop into new shoots and new plants in the next growing season
11
Q
examples of runners
A
- strawberry
- spider plant
12
Q
runners
A
- a lateral stem grows away from the parent plant
- roots develop where the runner touches the ground
- new plant develops
- runner with his away leaving the new plant independent
13
Q
examples of rhizomes
A
- marram grass
- ginger
14
Q
rhizomes
A
- specialised horizontal stem running underground
- swollen and stored with food
- develop and form new vertical shoots which become independent plants
15
Q
example of stem tubers
A
- potato
16
Q
stem tubers
A
- tip of an underground stem becomes swollen with stored food to form a tuber or storage organ
- buds on the storage organ developed to produce new shoots (eyes on a potato)
17
Q
how are natural clones used in horticulture
A
- splitting up bulbs, removing young plants from runners, cutting up rhizomes
OR - take cuttings of short sections of stems from many plants
- plant directly in the ground or in pots
- apply rooting hormone to base of the cutting
18
Q
six advantages of using vegetative propagation
A
- rapid production of plants
- affordable
- uniformity (plants all equally suited to environment)
- ability to colonize an area
- regenerate after damage (withstand insects, grazers, fire etc)
- back up if sexual reproduction fails
19
Q
disadvantages of vegetative propagation
A
- low genetic variation
- less stable and more effective by disease and climate change
- colonising weeds are disadvantages to other plants and humans
- slow spread and colonisation to new areas (don’t travel as far as pollen and seeds)
20
Q
why is an oblique cut in the stem made during vegetative propagation?
A
increase the surface area for rooting powder to stimulate root growth (under greater surface area for roots to grow from)
21
Q
why are leaves reduced a two or four for vegetative propagation?
A
- minimise water loss from transpiration
- lower energy demand
22
Q
why are cuttings useful for investigating the effect of growing conditions on plants?
A
- cuttings are genetically identical which serves as a control variable
- any changes in growth are a result of growing conditions
23
Q
micropropagation
A
the process of making very large numbers of genetically identical offspring from a single parent plant using tissue culture techniques
24
Q
why would you use micropropagation?
A
when the desirable plant:
- does not readily produce seeds
- doesn’t respond well to natural cloning
- is very rare
- has been genetically modified or selectively bred with difficultly
- is required to be pathogen-free by growers (e.g. strawberries, bananas, potatoes)
25
two propagation methods
- cuttings
- grafts (cut plant and attached to new plant)
26
steps in callus culture (and general principles of micropropagation and tissue culture)
- (using aseptic techniques) take a small sample of meristematic tissue from the shoot tips and axial buds of the parent plant
- surface sterilize the sample by immersing it into sterilising agents (does not need to be rinsed off)
- place the explant in a sterile culture medium containing a balance of plant hormones to stimulate mitosis
- cells proliferate, forming a massive identical cells known as a callus
- callus is divided into individual cells or clumps which are transferred to a new culture medium to stimulate growth of plantlets
- plantlets of potted into compost where they grow into small plants
- young plants are planted out to grow and produce a crop
27
what is put in a culture medium to culture plant tissue?
- auxins
- cytokinins
- water
- nitrates
- sucrose
28
what can be used to surface sterilise plant samples?
- bleach
- ethanol
- sodium dichloroisocyanurate
29
three types of tissue culture in plants
- meristem culture
- callus culture
- cell suspension culture
30
cell suspension culture and purpose (general)
- cells from callus culture can be suspended in a liquid medium in a bioreactor
- differentiated cells produce lots of a certain chemical rather than having to produce lots of the plant
31
32
five advantages of artificial plant cloning
- uniformity (same harvest time so all crops can be harvested at the same time)
- increase plant yield (rapid production)
- produce disease free crops by genetically modifying cuttings
- reproduce plants that are sterile or seedless (e.g. bananas)
- reliably increases the numbers of rare or endangered plants
33
four disadvantages of artificial plant cloning
- monoculture (lack of genetic variation/less stable)
- relatively expensive
- labour intensive and requires expertise
- aseptic conditions required for micropropagation
- contamination (parent plant can transfer pathogens or genetic disease to a large number of clones)
34
examples of natural clones in animals
- fragmentation (e.g. starfish)
- hydra produce buds which develop into clones
- some insects can reproduce asexually
- monozygotic twins
35
two types of artificial cloning in animals (general)
- reproductive cloning
- non-reproductive cloning
36
in SCNT, why are different breeds of animals used as the cell donor, the egg donor and the surrogate?
to make it easier to identify the original animal at each stage
37
steps in SCNT
- take a sample of somatic cells from an adult animal and culture them
- enucleate the somatic cells (optional)
- enucleate a mature ovum/egg cell (oocyte) from a different animal of the same species
- use a mild electric shock to fuse the somatic cell or just it's nucleus and the egg cell (electrofusion) and stimulate it to divide by mitosis
- embryo can be split up to produce multiple clones or increase the chance of success
- transfer the embryo into a surrogate
38
where does the DNA of a clone come from when using SCNT?
- DNA comes from the somatic cell
- mitochondrial DNA from the egg cell
39
two types of reproductive cloning (and why is it called reproductive cloning?)
- somatic cell nuclear transfer
- artificial embryo splitting
(the end result is a live animal)
40
uses of SCNT
- pharming
- produce genetically modified animals which grow organs that have the potential to be used in human transplants
41
when would you use SCNT compared to artificial embryo splitting?
- SCNT used to clone adults
- artificial embryo spitting used to clone embryos
42
uses of artificial embryo splitting
produce maximum offspring from a pedigree animal (e.g. for farmers)
43
steps in artificial embryo splitting
- animal with desirable traits is treated with hormones to stimulate superovulation which releases more mature ova the normal
- ova may be fertilised naturally or by artificial insemination with the sperm from a male with desirable traits
- early embryos gently flushed out of uterus OR mature eggs removed and fertilised in a lab
- embryo split to produce several smaller embryos whilst all cells are still totipotent
- embryos grown in lab for a few days to ensure all is well
- embryos implanted into a different mother (single pregnancy carries fewer risks than twin pregnancies)
44
how many embryos are implanted into each surrogate?
- depends on how many embryos the species naturally produces
- e.g. only one embryo implanted into cattle as it poses fewer risks but multiple embryos are implanted into pigs because they have a larger litter size
45
six arguments for animal cloning
- artificial twinning increases offspring of high yielding farm animals
- artificial twinning allows first cloned embryos to be assessed before remaining frozen clones are implanted into surrogates
- SCNT enables multiple GM to be produced from one engineering procedure (important in pharming and therapeutic cloning)
- SCNT allows replacement of specific pets, pedigree animals or top race horses
- SCNT has potential to enable rare endangered or extinct animals to be reproduced
- clowned mice have been developed to live a normal lifespan
46
five arguments against animal cloning
- SCNT is a very inefficient process and requires many eggs to produce a single cloned offspring
- many cloned animal embryos failed to develop, miscarry all produce malformed offspring (this may lead to physical suffering and euthanasia which are unethical and it is not our place to decide to take life)
- many animals produced by cloning how shortened life spans (due to being the same age as the somatic cell)
- cloning pets or pedigree animals does not mean they will be the same as they will be affected by different environmental factors
- increasing population of rare, endangered or extinct animals by SCNT has been relatively unsuccessful so far
47
another name for non-reproductive cloning and its purpose
- therapeutic cloning
- make cells tissues and organs to replace those that have been damaged by disease, accident or age
48
three techniques to produce cells to be cloned for therapeutic cloning (and why are they useful)
- cancer cells
- replacing faulty genes in gene therapy
- stem cells
49
five potential uses of stem cells
- regenerate heart tissue damaged by heart attack
- production of liver to replace one damaged by disease
- repair nervous tissue damaged by multiple sclerosis
- repair of nervous tissue following a broken neck
- repair brain tissue in Parkinson's disease or Alzheimer's
50
advantages of using stem cells
- reduce chance of rejection
- no donor shortage
- stem cells are totipotent so have great potential
51
advantages of using cancer cells in therapeutic cloning
- immortal
- divide repeatedly and indefinitely
52
ways of setting up a gene bank
- freeze mature egg cells
- freeze sperm
- freeze embryos created by IVF/SCNT
- freeze tissue (used in SCNT)
- zoo/reserve
53
why is it necessary to treat the surrogate mother with hormones? (3 marks)
- synchronisation
- must be in correct phase of (fertility) cycle
- grow and maintain uterine lining
- for embryo implantation
54
explain how a procedure such as SCNT can help save an endangered species of mammal. (4 marks)
- doesn't require eggs from endangered species
- doesn't require female of endangered species for pregnancy
- avoids risk of pregnancy for endangered species
- can reproduce infertile individuals
- adult cells from a range of existing adults can be used to maintain genetic biodiversity
- embryos can be cloned
- increases rate of reproduction therefore growing population size
55
clone
a genetically identical copy of a singular parent cell or organism that can occur naturally via mitosis or asexual reproduction or artificially
