Biotechnology and Manipulating Genomes

• Chain terminating nucleotides stop replication.
• Primer DNA provide base pairs to template DNA.
• Somatic gene therapy is when the allele is inserted into the area affected by the disorder.
• Reverse transcriptase (enzyme), endonucleases or other restriction enzymes can be used to cut open a section of DNA.
• The vector is then ligated with the target DNA using DNA ligase.
• A clone is a genetically identical cell/ organism.
• Vegatative propagation is the production of new plants from a single parent plant by the growth of new shoots from the root or stem, using runners/ statons, bulbs, tubers, corms, or leaves.
• Runners/ statons : strawberry plants
• Tuber : potato, sweet potato
• Bulb : onions
• Corms : crocus
• Leaves : kalanchoe leaves
• Natural clones : asexual reproduction by mitosis
• Advantages of natural clones:

  • rapid
  • asexual
  • if the conditions are good enough, then they can have offspring
• Disadvantages of natural cloning:

  • overcrowding
  • no genetic diversity
  • suceptible to environmental change
• Taking plant cuttings:

  1. cut at a slant between the nodes
  2. dip in rooting powder (auxins)
  3. plant in wet soil
  4. cover with a bag (to create warm and moist environment)
• Tissue cultures:

  • sterilise plants and petri dish
  • put it in a nutrient medium (nutrients and hormones)
  • add auxins and cytokin at different ratios to form roots and shoots
• Advantages of tissue cultures:

  • less room
  • less time
• Disadvantages of tissue cultures:

  • All vulnerable to changes in environment
  • less genetic biodiversity
• Micropropagation : growing lots of new plants from meristem of a sample plant
• Micropropagation:

  1. select the sample plant
  2. add shoot stimulating hormone (auxin)
  3. add root stimulating hormone
  4. transfer
• Totipotent stem cells can differentiate into any cell type in the body, except placenta cells
• Multipotent is an adult stem cell that can differentiate into several different types of cells, but only from the organ they've come from.
• Reproducting cloning:

  1. IVF creates zygotes woth desired characteristics
  2. Divide by mitosis
  3. Seperated and continue to divide
  4. Placed into a surrogate mother
• Uses of reproductive cloning:

  • elite farm animals
  • genetically modified animals
• Somatic cell nuclear transfer: A technique used to create cloned embryos that have the same genetic information as the donor
• SCNT:

  1. egg obtained and nucelus is removed (enucleation)
  2. normal body cell from the cloning adult is isolated
  3. the complete adult cell/ its nucleus is fused with the empty egg cell by applying shock
  4. triggers egg cell to develop
• SCNT uses:

  • repair damaged tissue/ organs
  • grow new organs
  • skin for a graft
• Growing cultures in fermentation vessels: growing conditions within the fermenter are manipulated and controlled to obtain precise growing conditions
• Growing cultures in fermentation vessels controls:

  • temperature
  • type/ time of addition of the nutrient
  • oxygen concentration
  • pH
• Culture : population of one type of organism
• Standard growth curve stages:

  1. lag : population size increases slowly as it's adjusting to a new environment
  2. log (exponential) : increases quickly in favourable conditions, little condition, lots of food
  3. stationary : death = birth, not enough nutrients
  4. death : death rate is larger than the rate of reproduction and population decreases
• Number of cells = initial number x 2 ^number of divisions
• Asepsis: absence of unwanted microorganisms
• Aseptic techniques: any measure taken during a biotechnological process to prevent contamination by unwanted microorgansims
• Disadvantages of unwanted microorgansims:

  • competes with culture for food
  • reduces useful yield
  • causes spoilage
  • produce toxic chemicals
  • destroys the culture/ its products
• Aseptic techniques :

  • washing hands
  • cleaning with ethanol
  • burning
• Continuous culture : microorganisms are continuously grown, nutrients are added, waste products taken out
• Colony : cells that have all come from the same original cell
• stock concentration of bacterial cells = colony count on agar plate / (dilution factor x amount plated)