Cloning and Biotechnology

• Define the terms "clone", "asexual reproduction", "reproductive cloning", and "vegetative propagation".

  Clone - Offspring, produced by mitosis, that is genetically identical to the parent plant [organism]Asexual reproduction - The generation of new individuals, often naturally, using mitosis, to produce clones.Reproductive cloning - Using artificial cloning methods to produce 2 or more individuals that are clones of each other.Vegetative propagation - The production of plant clones from non-reproductive tissues.
• Define the term "perennating organ" and describe the link between perennating organs and vegetative propagation

  Perennating organ - Plant structures which allow them to survive adverse conditions. They contain stored food and can remain dormant in the soil.Vegetative propagation takes place from perennating organs after adverse conditions when they stop being dormant and the stores of food are used to grow new plants from the organ.
• Describe 4 ways in which plants naturally clone.

  Rhizomes - horizontal underground stemsStolons - horizontal above ground stemsTubers - swollen underground stemsBulbs - swollen, tightly packed, underground leaves
• Define the terms "horticulture" and "agriculture"

  Horticulture - The branch of agriculture that deals with just plantsAgriculture - The cultivation and breeding of animals, plants or fungi for food or other resources
• Describe how the production of natural clones is exploited in horticulture

  Creating new plants by splitting up bulbs, removing young plants form runners and cutting up rhizomes.Increases plant numbers cheaply and all have same genetics as parents - known and favoured characteristics
• Define the term "taking cuttings" and describe how the process is used in horticulture

  Removing and planting short sections of stem of a plant in order to produce clones of that plant.Used to increase plant numbers (quicker than growing from seed) all clones of parents - good stock so will crop well.
• Describe 6 ways in which the success rate of taking cuttings can be increased


  Use a non-flowering stem - resources not needed to maintain cells of flowers so can be used to grow rootsMake an oblique cut in the stem - larger surface area for roots to grow fromUse hormone rooting powder - encourages the growth of new rootsReduce leaves to two or four - reduces surface area so reduces transpiration rate as water uptake very low until new roots are well developedKeep cutting well watered - will die if not enough water and needs to establish roots before it can draw enough up itselfCover the cutting with a plastic bag for a few days - reduces loss of water while new roots establish
• Give 5 examples of crops that are propagated by cloning

  Sugar cane, Bananas, Sweet potatoes, cassava, tea and coffee
• Describe the advantages and disadvantages of propagating crops by cloning

  Pros: Large numbers of new plants esp. of sterile plants such as seedless grapes (please consumers), Reliably increasing numbers of rare plants and/or plants difficult to grow from seed, Allows stocks to be built up quickly, Known genetic profile so known to produce good quality crops, Uniform plants makes harvesting easier and produces uniform quality cropsCons: Produces a monoculture - all plants susceptible to same diseases or changes in growing conditions, labour intensive, pathogens can be passed from parents
• Draw a table to compare production of new individuals by seed with producing new individuals by taking cuttings

  Seed: Genetically diverse, long growing time, low cost, need to maximise pollination and provide ideal requirements for germination and seedling growth, favoured when low cost and genetic variety important, problems occur when plants difficult to grow from seed e.g. orchids or when sexual reproduction is unreliable, occurs naturally so no need for human intervention, dependent on seasonsCuttings: Clones of parents, short growing time, high cost/labour requirements, need to use non flowering stems and rooting hormone with plenty of watering, favoured when need good crop quickly and when plant has a high success rate for cuttings or clones are wanted, problems occur as are susceptible to drying out and pathogens can be transferred, there is guaranteed quality, monoculture is a problem
• Define the terms "tissue culture", "micropropagation", "explant" and "callus"


  Tissue culture - The method of growing plant cells, in isolation from the parent plant under sterile conditions in or on a nutrient culture medium of known compositionMicropropagation - The process of making large numbers of genetically identical offspring from a single parent plant using tissue culture techniquesExplant - The material removed from a parent plant for tissue cultureCallus - A mass of undifferentiated plant cells that has been grown from an explant
• Describe 5 reasons why micropropagation might be used to clone plants

  The desirable plant does not readily produce seeds - sexual reproduction not feasible so micropropagation is an alternativeThe desirable plant doesn't respond well to natural cloningThe desirable plant is very rare - sexual reproduction unlikely if different individual needed to pollinateThe desirable plant has been genetically modified or selectively bred with difficulty - produces viable numbers of identical plantsThe desired plant is required to be 'pathogen-free' - grown in sterile conditions and original explant is sterilised
• Describe the process of micropropagation by callus tissue culture.

  Take a small sample of tissue from plant - often meristem tissue from shoot tips and axial buds - in sterile conditions to avoid contamination.This explant is sterilised.Plac in sterile culture medium containing a balance of plant hormones (auxins and cytokines). Cells proliferate by mitosis forming a mass of identical cells known as a callus.Callus divided up and individual cells/clumps transferred to new medium which stimulates growth of plantlets.These are potted into compost to become small plants which are planted out to grow and produce a crop.
• Give 9 examples of plants that are commonly produced by micropropagation

  Potatoes, sugar cane, bananas, cassava, strawberries, grapes, chrysanthemums, Douglas firs, orchids
• Describe the arguments for and against micropropagation

  Pros: Can grow plants that are naturally infertile, rare or endangered, genetically modified or seedless for consumer tastes, known genetic profile, uniform crop, disease free, any season as tissue culture carried out indoorsCons: Conditions must be kept sterile - aseptic conditions and any infected cultures must be disposed of, expensive, if source material infected with virus clones will be too, large numbers of plants can be lost in the process, produces monoculture, labour intensive, explants and plantlets vulnerable to infection by moulds and other diseases during production
• Describe 5 examples of natural cloning in animals

  Mitotic parthenogenesis - Development of an embryo from an unfertilised egg formed by mitosis rather than meiosis so has full number of chromosomesDamage - Animal damaged - multiple pieces develop into new organismsMonozygotic twinning - one zygote splits and forms 2 embryosBudding - New organism develops from an outgrowth or bud due to cell division at a particular site. Attached until mature.Fragmentation - organism split into fragments which each develop into mature, fully grown individuals.
• Explain how, in some species, offspring may be produced without a mate but are not clones

  Parthenogenesis in which an egg is 'fertilised' by another egg or similar gamete, both from the mother. Due to the different alleles and random assortment and crossing over of meiosis which created the egg, the offspring although genetically similar will not be clones.
• Define the term "monozygotic" and describe how identical twins occur

  Monozygotic twins are formed from a single fertilised egg. It occurs when one egg is fertilised by one sperm and one zygote forms. At some point the early embryo splits in two and each half grows into a new individual.
• State the two ways of artificially cloning animals

  Embryo splitting and Somatic Cell Nuclear Transfer (SCNT)
• Describe the process of cloning animals by splitting embryos

  Gametes fuse to form zygote. Embryo develops to the 16-cell stage.Embryo is separated to individual cells.Each cell now develops further into a separate and identical embryo. Surrogate mothers have uterus made ready by hormonal treatment: increased vascularization, and uterus wall thickness prepares for pregnancy.Each embryo is implanted into a surrogate mother.Surrogate mothers carry cloned embryos to term. Identical cloned offspring born.
• Describe the process of cloning animals by nuclear transfer

  A donor cell is taken from the adult organism to be cloned. It can be male or female, and allows production of another organism of a species using all possible genetic material and without needing a breeding female of the species.Egg donor is super ovulated with hormones to produce many eggs, harvested from the ovaries. This may be from a closely related species to that providing the nuclear material.The nucleus from the donor cell is removed and the cytoplasm discarded.The nucleus is removed from the donor egg - it is enucleated.Donor nucleus and enucleated oocyte are fused by the application of an electric current causing membranes to fuse.The fused cell begins to divide normally forming an embryo. Surrogate mother has uterus made ready by hormonal treatment.Embryo is placed in the uterus of surrogate mother. This may be an animal of a closely related species.Embryo develops normally in the surrogate mother's uterus.Cloned organism is born with identical nuclear genetic material to the donor animal, but with different mitochondrial DNA from the organism that provided the oocyte.
• Describe the arguments for and against animal cloning

  Pros: Artificial twinning enables high yielding farm animals to produce many more offspring than normal reproduction. Guarantees success of passing on desired characteristics. If used to prevent rare animals from going extinct will prevent loss of genes or alleles from the species. Infertile animals can be reproduced. SCNT allows scientists to clone specific animals eg pets or top racehorses. SCNT allows GM embryos to be replicated and develop, giving many embryos from one engineering procedure.SCNT has the potential to enable rare, endangered and even extinct animals to be reproduced.Cons: Animals become genetically uniform, increasing susceptibility to disease. Animals may have low quality of life or shortened life span. Many cloned embryos fail to develop and miscarry, or produce malformed offspring. Not just desirable characteristics are passed on to clones. Difficult, time-consuming and expensive. SCNT has been relatively unsuccessful so far in helping endangered or extinct animals. SCNT is very inefficient - in most animals it takes many eggs to produce a single cloned offspring. Work force must be highly trained which is expensive.
• Define the terms "biotechnology" and "microorganism", and give examples of each

  Biotechnology - The industrial use of living organisms, or parts of living organisms, to produce food, drugs or other products. e.g. yoghurt, bread, beerMicroorganism - a microscopic organism e.g. bacteria, fungi
• Describe the reasons why microorganisms are so useful for biotechnological processes

  Grow rapidly in favourable conditions - generation time as little as 30minsOften produce proteins or chemicals that are given out into mediumCan be genetically engineered relatively easilyGrow well at relatively low temperatures (compared to chemical engineering etc.)All the conditions for optimum growth can be met in a fermenterTend to generate products that are in a more pure form than those generated via chemical processesCan often be grown using nutrient material that would otherwise be useless or even toxic to humans.
• Describe the processes of brewing, baking, cheese making and yoghurt production as examples of biotechnology

  Brewing - yeast respires anaerobically using glucose from grain and producing CO2 and ethanol.Cheese - Chymosin enzyme from rennet or GM yeast and lactic acid bacteria. Chymosin clots the milk. Bacteria convert lactose into lactic acid - sour and solidifying.Yoghurt - Lactic acid bacteeria clot milk and cause it to thicken as well as lowering the pH and causing a sour taste.
• Describe one example of a microorganism being used to directly make food for human consumption

  Single-cell proteinFungal hyphae converted into meat-like products
• Describe the advantages and disadvantages of using microorganisms to make food for human consumption

  Pros: Growth is not dependent on seasons, production can occur throughout the year to meet demand. Carbon and energy sources for microorganisms are relatively cheap. Factories containing fermenters are not as extensive as farms and can be established where the necessary infrastructure and raw materials exist. Has little natural flavour so can be made to taste like anything. Much easier to carry out genetic engineering and selective breeding on microorganisms than plants and animals. Microorganisms are high in protein and low in fat content. Microorganisms carry out multi step processes using many enzymes which is cheaper than separating it all out. There are fewer ethical issues than with livestock. Cheap and efficient in converting biomass to human food. Waste materials used as substrates.Cons: Viruses can infect bacteria and fungi. If this happens the production plant is shut down and sterilised. If other bacteria enter the fermenter they may compete with the bacteria being cultured so yields are not as high and further purifying may be necessary. Many people dislike the idea of eating microorganisms grown on waste. Microorganisms can produce toxins if the conditions are not maintained at the optimum. Microorganisms need to be carefully separated from the culture medium and then processed heavily to made the food products. Need sterile conditions that are carefully controlled which adds to the cost. Some people object to the use of genetically modified organisms in their food. The fungus extracted from the fermenter to make Quorn is high in nucleic acids which have to be removed before the food is safe - high processing costs reduce profit margins.
• Describe how penicillin is produced commercially, including the name of the microorganism and the conditions needed for the microorganism to grow well

  Fungi from Penicillium genus e.g. Penicillium chrysogenum. Penicillin is produced by the fungus to stop bacteria competing for resources. The fungus is grown under stress in a fed-batch process where nutrients are added throughout to replace the depletion.
• Describe how human insulin can be produced on a large scale using biotechnology

  GM bacteria - the gene for human insulin inserted into their DNA. Grown in a large scale industrial fermenter.
• Define the term "bioremediation" and describe two different approaches to bioremediation

  The use of microorganisms to break down pollutants or contaminants in the soil or water.Either using naturally occurring organisms and supporting them with extra nutrients and enhanced growing conditions to encourage the process OR using GM organisms, modified to be able to break down toxins they would not normally encounter.
• Describe two ways of culturing microorganisms in a laboratory

  Broth - liquid medium - grow throughout volume so much higher populations, can stir it to redistribute nutrients etc. and easy to transfer by pouring.Agar - solid medium - good for counting and isolating colonies so used for experiments and studying.
• Define the terms "contaminant", "aseptic technique", and "asepsis"

  Contaminant - Any unwanted microorganismAseptic technique - The measures taken to minimise the risk of contaminants entering cultures of microorganismsAsepsis - The absence of unwanted microorganisms
• Describe 3 aseptic techniques and measures used at laboratory and starter culture level

  Loop in bunsen flame before inoculationBunsen flame draws air up away from cultureMinimise opening time and only partially open the lid
• Describe 3 aseptic techniques and measures used at large-scale culture level.

  Steam sterilises fermenter between batchesNutrient medium sterilised to prevent addition of contaminantsConstant checks for contaminantsStainless steelFiltersMinimise additions to culture
• State 5 reasons why contaminants are a problem in industrial fermentation

  They may compete with the culture microorganisms for nutrients and spaceThey may reduce the yield of useful products from the cultureThey may cause spoilage of the productThey may produce toxic chemicalsThey may destroy the culture microorganisms and their products
• Define the terms "fermentation", "culture", "pure culture", "mixed culture", and "closed culture"

  Fermentation - The culturing of microorganisms both aerobically and anaerobically in fermentation tanks to produce any useful substance.Culture - A growth of microorganismsPure culture - A growth of microorganisms consisting of a single species.Mixed culture - A growth of microorganisms consisting of several speciesClosed culture - The growth of microorganisms in an environment where all conditions are fixed and contained. No new materials are added and no waste products of organisms are removed.
• Draw, label and annotate a graph of the standard growth curve for microorganisms in a closed culture.

  
• Suggest how adding nutrients or removing waste products during different phases would affect the shape of the standard growth curve

  Adding nutrients to the exponential phase extends it so stationary phase is at a higher population level (no effect on gradient)Adding nutrients to stationary phase extends it if the decline is due to nutrients running out.Adding to death phase may slow decline if nutrients running out is the issue.Removing waste at exponential phase extends it so stationary phase is at a higher population level (no effect on gradient)Removing waste at stationary phase extends it if decline due to waste build upRemoving at death phase could slow decline if there are enough nutrients
• Name 5 factors that may prevent exponential growth in a culture of bacteria, and for each explain why they become limiting

  SpaceNutrients e.g. glucose/respiratory substrateBuild up of toxic waste products - effect on pH or other toxicityTemperature - enzymespH - enzymesOxygen - aerobic respiration
• Describe a step by step method to investigate the effect of one factor on the growth of microorganisms

  Set up identical colonies in different conditions of temperature Set up serial dilutions of nutrients or pH at a set temperatureWhen counting the assumption is made that each of the colonies on an agar plate grows from a single viable microorganism. Serial dilutions are used of the original culture broth until you can count the number of individual colonies in a given volume. This then has to be scaled back up.