Recombinant DNA Technology

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Recombinant DNA Technology
2012-09-18 08:35:43

Year 12 Human Biology 3ab - Recombinant DNA Technology
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  1. Define Recombinant DNA Technology
    • Recombinant DNA is DNA that has had a gene added to it from another source.
    • Producing recombinant DNA involves a process in which a segment of DNA containing the required gene from a particular organism is isolated and tranfsferred to another organism.
  2. Resrtiction Enzymes:
    enzymes that cut DNA strands at specific sequence of base pairs (nucleotides).  Many different types cut at different points
  3. Ligation:
    Joining short strands of DNA into longer lengths
  4. Gel Electrophoresis:
    Technique to seperate out strands of DNA according to length in a gel bed with the use of a small electric charge.  Small strand move further than larger strands so giving the bar-code effects
  5. DNA microarrays:
    A chip with attatched known DNA that is used to analyse unknown specimens of DNA in tens of presence and abundance.
  6. Describe Polymerase Chan Reaction:
    technique to replicate many identical strands of DNA from an original strand
  7. Steps of PCR:
    • Denature - seperate strands
    • Anneal - add primers
    • Extend (primers) - make copies
  8. Describe gene cloning (DNA cloning):
    the production of exact copies (clones) of a particular gene or DNA sequence using genetic engineering techniques.  The gene is inserted into cloning vectors, such as bacterial plasmids, which transfer the recombinant DNA to suitable host cells such as bacteria.  The bacteria cells can then make many copies containing the cloned target gene.
  9. Transgenic Organisms:
    organism whose genome has been altered by the transfer of gene(s) from another organism
  10. DNA Profiling:
    the determination of an organisms individual DNA sequence often using gel elctrophoresis (genetic fingerprinting)
  11. Gene Therapy:
    • Gene therapy attemps to correct defective genes for such disorders as Huntington's disease, cycstic fibrosis and Duchenne muscular dystrophy in 3 ways:
    •  - replace faulty gene with normal gene
    •  - provide a corrective gene
    •  - blocks the faulty gene activity
  12. Steps in producing recombinant DNA:
    • 1. the required gene is cut from a DNA molecule using a restriction enzyme.
    • 2. A bacterial plasmid is isolated and cut with the same restriction enzyme.  This ensures cut ends are complementary (same base sequences) to the ends of the required gene
    • 3. The required gene is joined to the plasmid using the enzyme DNA ligase in a process called ligation
    • 4. The resulting recombinant plasmid is returned to the bacterial cell.
    • 5. The bacteria reproduce and the required gene is cloned.
  13. DNA enzymes:
    • Ceratin enzymes, generally termed nucleases, are involved in the synthesis, binding and breaking up of DNA.
    • It it important to realise that the DNA enzymes in one species can be ysed to work on the DNA of other species.  This is because the structure of DNA is the same for all species.
  14. What are the Base pairs of a triple bond?
    Guanine and Cytosine
  15. What are the base pairs of a double bond?
    Adenine and Thymine
  16. What is DNA?
    • Phosphate and sugar molecules alternate to form the spiral lattice that holds the paired nitrogenous bases.
    • The code for the proteins can be altered by simply changing any single bases pair.  A sequence of three base pairs makes a codon which is a simple amino acid.
    • The sequence of amino acids (codons)makes up a gene which is a template for a protein.
  17. What do Genes do?
    • Genes contain the coded formula needed by the cell to produce proteins.  Proteins are the most common of the complex molecules in your body.  Types of proteins include:
    •  - structural proteins, 
    •  - messenger proteins, 
    •  - enzymes
  18. Structural Proteins:
    such as those which form hair, skin and muscle
  19. Messenger Proteins:
    such as hormones, which travel around your body controlling such things as the sugar content of your blood.
  20. Enzymes:
    which carry out most of the lide processes inside your body, for example making haemoglobin for your red blood cells
  21. Making Proteins
    • Protein synthesis requires two steps:

  22. DNA VS RNA:
     - sugar
     - bond with adenine
     - No. of strands
    • DNA:               
    • deoxyribose
    • thymine
    • two

    • RNA:
    • ribose
    • uracil
    • one
  23. Messenger RNA (mRNA)
    • Messenger RNA contains genetic information.  It is a copy of a portion of the DNA.  
    • It carries genetic information from the gene (DNA) out of the nucleus, into the cytoplasm of the cell where it is trasnlated to produce protein.
  24. Transfer RNA (tRNA)
    Transfer RNA functions to transport amino acids to the ribosomes during protein synthesis.
  25. Explain the processes of Transcription:
    • 1. An enzyme Helicase, enters the nulceus binding to the gene (protein) that needs to be copied.
    • 2. This causes an enzyme RNA polymerase to 'unzip' the DNA strand at that point and move along it until it reaches a sequence of bases called the promotor
    • 3. mRNA brings in complimentary (opposite) base pairs and attatches them to each base pair as the RNA polymerase moves along the strand until the whole length is complete.
    • 4. The completed complimentary strand travel detaches and travels to a ribosome.
  26. Explain the process of Translation:
    • 1. mRNA attatched to ribosome
    • 2. Ribosome travels along the mRNA reading the code
    • 3. tRNA brings complimentary amino acids from cytoplasm to attatch to the mRNA
    • 4. The complete strand is made becoming a protein.
    • This process can be repeated many times on many ribosomes so large amounts of a protein can be made from a single strand of DNA very rapidly.
  27. How genes work:
    • Gene expression is the process of converting information on a gene into a protein.
    • Hormones, vitamins, minerals, chemicals and pathogens either formed by the ells or entering the cells may switch on or off certain genes.  This determines which proteins are produced by the cell.
  28. Regulator genes:
    produce proteins that bind to operator genes and stop transcription
  29. Promotor Genes:
    A type of regulator gene that switches structural genes on.  It is the site where RNA polymerase binds and initiates transcription
  30. Operator Gene:
    Starts production of messenger RNA (mRNA) in structural genes
  31. Structural Genes:
    codes for the production of amino acids in proteins