6.4 Cloning and Biotechnology Flashcards
Define clone.
Genetically identical organisms or cells.
Define vegetative propagation?
Reproduction from vegetative parts of a plant- usually an over-wintering organ.
What are clones produced by?
Clones are produced by asexual reproduction in whihc the nucleus is divided by mitosis.
What does mitosis produce?
Mitosis creates 2 identical copies of DNA, which are separated into 2 genetically identical nuclei before the cell divides to form 2 genetically identical cells.
What differences do 2 cells produced from mitosis have?
These cells may not be physically or chemically identical as, after division, they may diffrentiate to form 2 different types of cell.
What is produced when an organism reproduces asexually?
A clone.
Give 2 examples or organisms that reproduce asexually?
Both single-celled yeasts reproduce by budding and bacteria reproduce by binary fission. Both processes involve exact replication of DNA, so the cells produced are genetically identical.
How is an offspring produced by cloning identical to the parent?
They’re genetically identical.
What are the advantages of reproduction by cloning?
- If conditions for growth are good for the parent, they will be good for the offspring.
- Cloning is relatively rapid- so the population can increase quickly to take advantage of the suitable enviromental condiations.
- Reproduction can be carried out , even if there is 1 parent and sexual reproduction is not possible.
What are the disadvantegs for cloning?
- The offspring may become overcrowded.
- There will be no genetic diversity(except that caused by mutation during DNA replication).
- Population shows little variation.
- Selection is not possible.
- If the enviroment changes to be less adventageous, the whole population is susceptible.
How is the differentiation of plant and animal cells different?
The differentiation of many plant cells is not as completer as in animals.
Why are plants able to reproduce by cloning?
Many parts of a plant contain cells that retain the ability to divide and to differentiate into a range of different cells.
What process does natural cloning involve?
Vegetative cloning.
What is vegetative cloning?
The is the process of reproduction through vegetative parts of the plant, rather than through specialsed reproductive structures.
What are the stems called on a plant that grow horizontally and can grow roots?
- Runners or stolens if they grow on the surface of the ground.
- Rhizomes if they grow underground.
How are some rhizomes adapted?
Some rhizomes are adapted as thickened over-wintering organs from which one or more new stems will grow from in the spring.
What is the new stem that grows from a root of another plant called?
Suckers
What is a sucker?
New stems that grow from a plants root. In all cases, the orginal horizontal branch will die, leaving the new stem as a separate individual.
What is an over-wintering mechinism for many perennial monocotylendonous plants?
Bulbs.
For what sort of plant are bulbs an over-wintering mechanism for?
perennial monocotylendonous plants.
What does a bulb consist of?
They consist of an underground stem which grow from a series of underground bases. There is also an apical bud, which will grow into a new plant in the spring.
How many apical buds does a bulb contain.
Bulbs often contain more than one apical bud and both will grow into a new plant.
What is the difference between a corm and a bulb?
Corms are solid while bulbs are fleshy.
What is a corm?
A corm is an underground stem with scaly leaves and buds.
How many plants will a corm produce?
A corm will produce 1 or more new plants.
What plants reproduce using corms?
- Croci
- Gladioli
How does a Kalanchoe plant reproduce asexually?
Clones hrow on the leaf margins. The immature plants drop off the leaf and take root.
What is a tuber?
A tuber is a type of underground stem. Potatoes are tubers. One tuber will grow into 1 or more plants. Each new plant can then produce many new tubers for later that year.
What are some examples of vegetative parts of a plant?
- Bulbs
- Corms
- Tubers
When do mammals clone?
When identical twins are formed. This occurs when a fertilised egg (zygote) divides as normal, but the 2 daughter cells then split to become 2 separate cells. Each cell grows and develops into a new individual.
What animals commonly reproduce asexually to produce clones?
- Water flea (Daphnia pulex)
- Greenfly (Acyrthosiphon pisum)
Define micropropogation?
Growing large numbers of new plants from meristem tissue taken from a sample plant.
Define tissue culture.
Growing new tissues, organs or plants from certain tissues cut fro a sample plant.
What is the easiest way to create clonmes of a plant?
Through taking cuttings.
How would you take a cutting of a plant.
Cut between 2 leaf joins (nodes). The cut end of the stem is then placed in moist soil. New roots will grow from the tissues in the the stem-usually from the node, but may grow from other parts of the buries stem.
How can it be made easier to get a cutting to root?
- Dipping the end of the cut stem in rooting hormone helps to stimulate root growth.
- Also helpful to wound or remove the bark from the cut end of the stem as this encourages the plant to produce callus.
What parts of a plnt can a cutting be made from?
- Root cutting, in which a section of the root is buried kust below the soil surface, and produced new shoots.
- Scion cuttings, which are dormant woody twigs.
- Leaf cuttings, in which a leaf is placed on moist soil. The leaves gevelop new stems and new roots. Some leaves may produce many new plants from one cutting.
What are some disadvantages of taking cuttings?
The process can be time-conduming and can take up a lot of space. Also some plants do not responf well to taking cuttings.
How are many houseplants commercially clones?
Via tissue culture techniques.
What is tissue culture?
Tissue culture is a series of techniques used to grow cells, tissues or organs from a small sample of cells or tissue.
How is tissue culture carried out?
Tissue culture is carried out on a nutrient medium under sterile conditions.
During tissue culture, how can cells be encouraged to differentiate?
CElls can be encouraged to differentiate by the application of plant growth substances at the correct time.
What is tissue culture widely used in commercially to increase the number of new plants?
Tissue culture is used in micropropogation.
What does micropropogation involve?
It involves taking a small piece of plant tissue (the explant) and using growth substances to encourage it to grow into a whole new plant.
What are the steps of micropropogation?
- Suitable plant material is selected and cut into small pieces. These are called explants. Explants could be tiny pieces of leaf, stem , root or bud. Meristem tissue is often used, and this is always free from virus infection.
- The explants are sterilised using using dilute bleach or alcohol. This is essential to kill any bacteria and fungi, as these would thrive in conditions to help the plant grow well.
- The explants are placed on a sterile growth medium (usually agar gel) containing suitable nutrients such as glucose, amino acids and phosphates.
- The gel also contains high concentrations of the plant growth substances auxin and cytokinin. This stimulates the cells of each explant to divide by mitosis to form calllus (a mass of undifferentiated, totipotent cells).
- Once a callus is formed, it is divided to produce a larger number of smaller clumps of undifferentiated cells.
- These small clumps of cells are stimulated to grow, divide and differentiate into different plant tissues. This is achieved by moving the cells to different growth media. Each medium contains different ratios of auxin and cytokinin.
- Once tiny plantlets have been formed, these are transferred to a greenhouse to be grown in compost or soil and acclimatised to normal growing conditions.
In micropropogation, what is the small piece of plant tissue used called?
The explant
In micropropogation, what does the agar gel contain to promote the cells to expand to divide by mitosis to form callus?
High concentrations of auxins and cytokinins.
What is callus?
A mass of undifferetiated, totipotent cells.
What is totipotent?
Stem cells that are able to differentiate into any type of cell.
In micropropogation how do they get clumps of cells to grow, divide and differentiate into different plant tissues?
By moving the cells to different growth media- each media contains different ratios of auxin and cytokinin.
In micropropogation, when stimulating clumps of cells to grow, divide and differentiate into different plant tissues, what does the first medium the plant is put in contain? What does his cause?
It contains the ratio 100 auxin:1 cytokinin and this stimulates roots to form.
In micropropogation, when stimulating clumps of cells to grow, divide and differentiate into different plants tissues, what does the second medium the plant is put in contain? What does this contain?
It contains the ratio 4 auxin : 1 cytokinin, which stimulates the shoots to form.
What are the advantages of artificial cloning?
- Cloning is a relativley rapid method of producing new plants compared to growing plants from seed.
- Cloning can be carried out where sexual reproduction is not possible.
- The plants selected will be genetically identical to the parent plant.
- If the original plant had an unusual combination of characteristics due to selective breeding or genetic modification, then this combination can be reunited without the risk of losing that combination through sexual reproduction.
- New plants will be uniform in their phenotype.
- Using the apical bud (meristem) as an explant for tissue culture ensures plants are free from viruses.
In artificial cloning, why is the fact cloning can be carried out where sexual reproduction is not possible an advantage?
Plants that have lost their ability to breed sexually can be reproduced. Plants that are hard to grow from seed can be reproduced.
In artifcial cloning, why is it an advantage that plants selected will be genetically identical to the parent plant?
They will display the same desirable characteristics such as a yield, resistance to a common pest or disease, or a particular colour of flower.
What are the disadvantages of artificial cloning?
- Tissue culture is labour intensive.
- It is expensive to set up facilites to perform tissue culture successfully.
- Tissue culture can fail due to microbial contamination
- All the cloned offspring are genetically identical and are therefore susceptable to the same pests and diseases.
- Crops are grown in monocultures allow the rapid spread of a disease or pest between closely planted crop plants.
- There is no genetic variation, except that introduced by mutation.
How could you carry out an investigation on cloning cauliflower?
- Cut a mini-flouet from a cauliflower. Cut the floret into small 3-5mm piece, these are the explants.
- Transfer the explants to a sterilising solution, such as sodium dichlorisocyanurate and swirl the solution peridically.
- After 15mins, transfer the explants onto a sterile nutrient agar surface in a specimin tube. Use aseptic techniques to avoid contamination.
- Incubate in a warm lab. Growth and greening of some tissues should be visable within 2 weeks.
Define embryo twinning?
Splitting an embryo to create 2 genetically identical embroys.
Define enucleation?
Removal of the cells nucleus.
Define somatic cell nuclear transfter?
(SCNT) is a technique that involves transferring the nucleus from a somatic cell to an egg cell.
What can most cloning in animals be described as?
Artifical
What does successful cloning start with?
Totipotent cells.
Where can totipotent cells be found in animals?
Only truy totipotent cells are found in very early embryo cells.
What does reproductive cloning produce?
Reproductive cloning produces a large number of genetically identical animals.
What is reproductive cloning useful for?
- Elite farm animals produced by selective breeding or genetic modification. e.g. a good bull can supply sperm for artificial insemination.
- Genetically modified animals developed with unusual characteristics.
What are the 2 main tyechniques used to achieve reproductive cloning?
- Embryo twinning
- Somatic cell nuclear transfer (SCNT)
How does the process of embryo splitting for reproductive cloning taje place?
- A zygote is created by in vitro fertilisation (IVF)
- The zygote is allowed to divide by mitosis to form a small ball of cells.
- The cells are separated and allowed to continue dividing.
- Eacxh small mass of cells is placed into the uterus of a surrogate mother.
What is embryo splitting used for?
The techniche has been used to clone elite farm animals or animals for scientific research.
What will the offsprings phenotype and genotype be like for an animal that has undergone embyo splitting?
The precise genotype and phenotype of the offspring will depend of the egg and sperm used. So, the precise phenotype will be unknown untill the animals are unkown.
What is trhe diagram showing?
Embryo splitting
What is the only way to clone an adult?
Somatic cell nuclear transfer (SCNT).
What is the advantage of SCNT?
The phenotype is known before cloning starts.
What mammal was the process SCNT first used on?
In 1996, to produce dolly the sheep.
How does somatic cell nuclear tansfer occur?
- An egg is obtained and it’s nucleus is removed, known as enucleation.
- A normal body cell (somatic cell) from the adult to be clones is isolated and may have its nucleus removed.
- The complete adult somatic cell or its nucleus fused with the empty egg cell by applying an electric shock.
- The shock also triggers the egg cell to start developing as though it had been fertilised.
- The cell undergoes mitosis to produce a small bundle of cells.
- the young embryo is placed into the uterus of a suragte mother.
What does the diagram show?
Somatic cell nuclear transfer (SCNT).
What is non-reproductive cloning?
Non-reproductive cloning is the production of cloned cells and tissues for other purposes than reproduction.
What is an example of non-reproductive cloning?
Theraputic cloning.
What is achieved through theraputic cloning?
New tissues and organs can be grown as replacement parts for poeple who are not well.
What are some examples of tissues and organs that can be grown via theraputic cloning?
- Skin can be grown in vitro to act as a graft over burned areas.
- Cloned cells have been used to repair damage of the spinal cord of a mouse to restore the capability to produce insulin to the pancreas.
- There is the potential to grow whole organs to replace diseased organs.
What is an advantage of using a patients own cells for theraputic cloning?
Glowing tissues from a patients own cells will mean the tissues will be genetically identical and so avoid rejection , which is a problem when transplanting donated organs.
What can clonong genetically identical embroys be used for in scientific research?
Research into the action of genes that control develpoment and differentitation. They can also be used to grow specific tissyes or organs for use in tests on the effects of medicinal drugs.
What are the 6 arguments for artificial cloning in animals?
- Can produce a whole herd of animals with a high yeild or that show an unusual characteristic.
- Produces genetically identical copies of very high value individuals retaining the same characteristics.
- using genetically identical embryos and tissues allows the effects of genes and hormones to be assessed with no interference from different genotypes.
- Testing medicinal drugs, avoids testing animals or humans.
- Produces tissues identical to the donor.
- Individuals from an endangered species can be cloned to incerase numbers.
What are 6 arguments against artificial cloning in animals?
- Lack of genetic variation may expose a herd to pests.
- Animals may be produced with little regard for their wellfare.
- The success rate of adult cell cloning is very poor and the methird is a lot more expensive than conventional breeding.
- Clones may be less healthy and have a shorted lifespan.
- There are ethical issues regarding how long the embryo survives and weather it is right to create a life then destoy it.
- It does not increase genetic diveristy.
Define biochenology?
biotechnology is the use of living organisms or part of living organisms in an industrial process.This could be to produce food, drugs or other products.