Module 6 - Cloning & Biotechnology Flashcards
What is a clone?
Clones are a genetically identical to their one parent. They are formed by asexual reproduction (mitosis in eukaryotes; binary fission in prokaryotes).
Name some examples of natural clones
1) Identical twins 2) leaves - Vegetative propagation 3) Runners - Vegetative propagation 4) Tubers - Vegetative propagation 5) Bulbs - Vegetative propagation
What is vegetative propagation?
The production of structures in a plant that can grow into new plants which are genetically identical to the parent (clones). i.e natural plant cloning. How do you think this is possible? Many parts of the plants contain tissues that have not differentiated, so can divide to form a range of different cell types.
Advantages and disadvantages of natural clones
ADV: Quick, Possible when sexual reproduction isn’t possible, All offspring have genes to survive environment. DIS: Overcrowding, No genetic variation.
summarise how a plant cutting is taken.
- the stem is cut at a node (two leaf joints). 2. remove bark if present to avoid the formation of a callus. 3. add rooting powder depending on plant species (some will take root less easily). 4. the cut end of the stem is buried into soil. 5. new roots will begin to grow into the soil. 6. this process is also possible from root cuttings, scion cuttings (in woody twigs) and leaf cuttings.
Describe the production of artificial clones by micropropagation and tissue culture
• Tissue from apical buds (an explant) taken because it is meristematic and therefore undifferentiated and can still undergo mitosis. • Surface is cleaned using sterilising agent to ensure aseptic conditions so that no bacteria can grow as it could compete with the plant tissue. • Explant is placed onto nutrient medium to encourage mitosis this produces a callus (mass of undifferentiated cells). • The callus is subdivided and placed in a new nutrient medium which will encourage differentiation of tissue. It contains: • >auxins ‐ stimulate formation of root hairs • >cytokinins ‐ stimulate shoot growth • >magnesium ‐ helps the plant make chlorophyll • >nitrates needed for protein synthesis • >sucrose ‐ converted to glucose for respiration • The callus cells will grow into plantlets and can be then placed sterile soil
Describe some advantages and disadvantages of artificial cloning
Advantages of clones (rather than seeds)… • genetically identical • maintains favourable characteristics • quicker to produce • more likely to survive • more produced • disease free • easily genetically manipulated • can be used for cloning infertile plants • easy to transport/store Disadvantages of clones (rather than seeds)… • Genetically identical ‐ all susceptible to same diseases • Loss in genetic diversity • Farmers have to buy the plants from suppliers • Patented property ‐ high cost ‐ can’t replicate them yourself
What are two methods which can be used to artificially clone animals?
1) Embryo twining 2) Somatic cell nuclear transfer
Describe the production of artificial clones by embryo twining
- A zygote is created by IVF. 2. It is allowed to divide to form a small ball of cells. 3. These cells are separated and continue to divide. 4. Each of these cells is placed into a surrogate mother. This method is used for: - Cloning elite farm animals - Scientific research
Why is a clone is not entirely genetically identical to the nucleus donor?
DNA is also found in mitochondria Only get DNA from nucleus in clones (not their cytoplasm) Mitochondrial DNA is found in cytoplasm.
How are surrogates prepared for implantation of an emryo?
- Hormone treatments
- To prepare uterus for implantation by causing the lining to thicken so there is an increased blood supply for the placenta
How are eggs collected for IVF?
Treated with hormone (FSH)
Superovulation
Collect eggs from ovaries
What is meant by therapeutic cloning?
Therapeutic cloning means news tissues and organs can be grown and replaced in patients where damaged e.g. skin grafts, pancreatic cells producing insulin, spinal cord damage.
Arguments for and against the artfificial cloning of animals
For:
- Produces genetically identical copies of very high value individuals.
- Testing medicinal drugs on cloned cells and tissues avoids using animals or people for testing.
- Can produce cells and tissues genetically identical to the donor, for use in repairing damage caused by disease or accidents.
- Individuals from an endangered speices can be cloned to increase numbers.
Against:
- Lack of genetic variation may expose a herd to disease.
- The success rate of adult cloning is very poor and the method is a lot more expensive than conventional breeding. Cloned animals may be less healthy and have shorter life spans.
- There are ethical issues regarding how long the emrbyo survives and whether it is right to create life or simply destroy.
Explain how cloning might help preserve a species
increases rate of reproduction ;
does not require species∔ eggs ;
so does not require fertile female ;
does not require female for pregnancy / uses surrogate ;
female not put at risk in, travel / mating / pregnancy ;
successfully formed embryo can be, subdivided / cloned ;
can use adult cells from all existing animals to maintain diversity
Describe and explain as many factors that you need to be controlled when using fermenters to maximise product yield
- Temperature is kept constant by cooling water
- PH- optimum PH for enzymes to have the fastest rate of reaction
- Stirrer- provide a good flow of oxygen for aerobic reactions taking place
- Carbon, nitrogen, vitamins and minerals needed for growth
- Sterile air for aerobic conditions to avoid contamination and prevent other products being formed
Describe and explain the normal growth curve
Sationary phase- growth has stopped. The rate of reproduction and death rate are equal.
Death phase- the death rate is higher than the reproductive rate. The competition meant the nutrients available cannot not sustain the rate of reproduction.
