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DNA replication
DNA replication
DNA replication
DNA replication
DNA replication
DNA replication
DNA replication
DNA replication
DNA replication
DNA replication
DNA replication
DNA replication
DNA replication
DNA replication
DNA replication
DNA replication
DNA replication
DNA replication
DNA replication
DNA replication
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DNA replication


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  • 1. Unit B5 & 6: Cell Biology (DNA Replication ) Authored by Michelle Choma ©
    • Students who have fully met the prescribed learning outcomes (PLO’s) are able to:
    • B5. Describe DNA replication.
    • Describe the three steps in the semi-conservative replication of DNA:
      • “ unzipping” (DNA helic ase )
      • complementary base pairing (DNA polymer ase )
      • joining of adjacent nucleotides (DNA polymer ase )
  • 2. This is it!! Short one Eh!?
    • Describe the purpose of DNA replication.
    • Identify the site of DNA replication within the cell.
    • B6. Describe recombinant DNA.
    • Define recombinant DNA.
    • Describe a minimum of three uses for recombinant DNA.
  • 3. Introduction
    • Recall the structural composition and functions of DNA. See B4
  • 4. DNA Replication
    • Purpose :
    • Before a cell divides, it needs to double the number of chromosomes (containing genes/traits, codons/protein codes)
      • i.e. the DNA is duplicated for each new daughter cell.
  • 5. Location :
    • Nucleus, mitochondrion (and plant chloroplasts); requires 2 enzymes helic ase and DNA polymer ase .
    Helicase DNA Polymerase
  • 6. Products :
    • 2 DNA molecules; 1 identical to original.
    • This is known as semiconservative replication , which produces two “half-old and half-new” DNA strands.
  • 7.  
  • 8. 3 basic steps:
    • 1.) Unzipping
    • 2 strands of DNA unwind AND unzip the H-bonds between N-base pairs using helic ase .
  • 9. Next step
    • 2.) Complementary base pairing
    • New nucleotides present in the nucleus (T, C, A, G) bond with the complementary pairs on the parental strand
      • i.e. A-T, G-C, T-A, and C-G using DNA polymer ase
  • 10.  
  • 11.  
  • 12. And lastly….
    • 3.) Joining of adjacent nucleotides
    • Adjacent nucleotides join/form a bond with the help of DNA polymer ase (“proof-reader”) to form new sugar-phosphate backbones resulting in 2 identical DNA molecules. This is referred to as semi-conservative .
  • 13.  
  • 14. Recombinant DNA (rDNA)
    • Definition:
    • DNA/genome from two different organisms are spliced together to obtain a desired trait/characteristic or perform a specific function; the manipulation of a genome from two or more sources, such as bacteria, plants or animals.
      • E.g. Bacteria nucleic acid containing a human hormone gene and producing biotechnology products, i.e. insulin, growth hormone.
  • 15.  
  • 16. Uses:….there are lots!
    • Production of hormones (insulin, growth hormone), human proteins (interferon, antibodies) and vaccines from bacteria.
    • Development of pest-resistant, frost-resistant, disease-resistant, altered oil content and ripening etc. in crops. Plants can also be engineered to produce human hormones, proteins, and antibodies.
    • Production of DNA probes for paternity/maternity, body ID at crime scenes, evolutionary relationships etc.
  • 17. Some more
    • Transgenic animals, or genectically altered organisms (GMO’s) to increase productivity, produce pharmaceuticals, produce organs, research in cancer/tumour cells etc.
    • Transgenic bacteria used for vaccines, biofilter airborne pollutants, synthesize hormones, enzymes for making cheese, clean oil spills, extract precious metals in mining.
    • In medicine for the diagnosis and treatment of genetically inherited disorders, e.g. cystic fibrosis
    • To give an organism a metabolic capability it did not possess before.
    • To create more copies of a specific gene so it can be studied.
  • 18. What do this fish and
  • 19. This ice cream have in common?
  • 20. mmmmm……smooth ice cream
    • “ Anti-freeze” gene from arctic pout are inserted into a yeast which then generates the anti-freeze protein
    • This protein is added to ice cream to make it smoother (smaller ice crystals)
    • Hmmmm…. Is this a good idea? What do you think?