6.2.1 - biotechnology and cloning

    Cards (50)

    • Natural clones of plants can be produced by vegetative propagation
    • vegetative propagation is when part of a plant is separated then develops into a new plant genetically identical to the original.
    • for cloning, a plant cutting is when the stem is cut between the leaf and the nodes. The cutting is then replanted and allowed to grow, sometimes with the use of plant hormones.
    • to produce artificial clones of plants we can either use
      tissue culture
      micropropagation
    • tissue culture is when the sample is placed on various nutrient containing mediums to encourage cell division and shoot growth
    • micropropagation is when material produced from tissue culture is rapidly multiplied to produce large numbers of plants.
    • + of using plant cloning in agriculture is that large numbers of plants can be produced regardless of weather conditions.
    • negative of using plant cloning in agriculture is that it reduces genetic variation, making them more susceptible to disease.
    • natural cloning in animals is monozygotic twins.
      where the embryo splits during development to produce two genetically identical individuals.
    • We can produce artificial clones of animals by either
      embryo splitting
      somatic cell nuclear transfer
    • somatic cell nuclear transfer is when differentiated cells from parent are fused with an enucleated egg cell. the cell develops into an embryo and can be implanted into a womb.
    • embryo splitting is the process of splitting an embryo into two embryos to produce two clones.
    • + of cloning in animals is that it can preserve endangered species. and that it is a quick process suited to the growing population of earth.
    • negatives of cloning in animals is that is gives cells a low genetic diversity. and cloned animals often suffer from health problems and genetic disorders.
    • Microorganisms are suited for use in biotechnological processes because they have rapid growth in a variety of environmental conditions. they can be genetically engineered and it reduces the use of chemicals so is beneficial to the environment.
    • microorganisms are used in biotech processes:
      • Making food - baking, brewing, yoghurt, cheese
      • medicine - penicillin, insulin
      • Environmental - removing pollution. Bioremediation.
    • + of using microorganisms to produce food:
      • Production rate easily varied
      • not dependent on climate
      • long lasting
      • uses waste products
    • disadvantages of using microorganisms to produce food:
      • lack of flavour
      • proteins must be isolated and purified
      • contains different amino acids to animal proteins
    • aseptic techniques should be used to culture microorganisms.
    • aseptic techniques are when everything is kept completely sterile so that no unwanted microorganisms are present in the culture.
    • the three steps of growing microorganisms are:
      1. sterilisation - using aseptic techniques
      2. inoculation - microorganism introduced to agar
      3. incubation - placed in warm environment for 24-48 hours to grow
    • the two types of fermentation are
      batch fermentation
      continuous fermentation
    • Batch fermentation is in a closed environment. Maintains the culture in the stationary phase - then left to death phase. Whole batch is removed and sterilised so a new batch can be added.
    • continuous fermentation is when the products are continually removed so maintains culture in exponential phase.
    • Batch fermentation favours secondary metabolites.
    • continuous fermentation favours primary metabolites.
    • Growth conditions are manipulated inside fermenter to maximise yield by:
      • temperature maintained at optimum
      • sufficient nutrient supply
      • aerobic conditions to prevent products of anaerobic respiration
      • ph kept constant to maximise enzyme activity
    • growth curve of microorganisms in a closed culture has 4 phases:
      1. lag phase = cells increase in size and take in nutrients. constant population.
      2. exponential phase = cells divide. population increases exponentially.
      3. stationary phase = nutrient levels decrease, slowing growth rate. population stabilises.
      4. death phase = population declines as the cells start to die.
    • Formula for bacterial growth
      N = N0 x 2^n
      N = number of bacteria in population
      N0 = initial number of bacteria in population
      n = number of divisions
    • An immobilised enzyme is an enzyme attached to an inert material in order to restrict its movement and hold it in place during a reaction.
    • Methods of immobilising enzymes are:
      1. bonding = binds with support Ionically ( adsorption ) or covalently
      2. entrapment = placed in a semipermeable material that allows diffusion of substrate and product
      3. membrane separation = partially permeable membrane separates enzyme from substrate
    • some uses of immobilised enzymes are:
      • glucose to fructose conversion
      • semisynthetic penicillin production
      • lactose to glucose / galactose conversion
      • pure samples of amino acids
      • dextrins to glucose conversion
    • + of immobilised enzymes
      product is not contaminated by enzyme so does not need to be purified
      enzymes can be reused
      enzymes are protected from harsh environment
    • negatives of using immobilised enzyme:
      expensive
      reaction rate is slower as enzymes cannot move
    • To produce clones from cuttings:
      Use a healthy shoot; cut stem at a slant between nodes; dip in rooting powder; place in soil and add water; to reduce transpiration cover with plastic bag.
    • Grafting is joining the shoot of one plant to the growing root or stem of another plant
    • Adv of cloNing:
      • clone seedless fruit
      • can have desired trait
      • quick growth
    • dis adv of cloning:
      • low genetic diversity
      • unlikely to survive a disease
    • Tissue culture is growing plants from a cell based medium
    • mitosis and asexual reproduction produces natural clones
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