SL Content Statements

• D1.1.1

  DNA replication as production of exact copies of DNA with identical base sequences

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  Students should appreciate that DNA replication is required for reproduction and for growth and tissue replacement in multicellular organisms.
  

• D1.1.2

  Semi-conservative nature of DNA replication and role of complementary base pairing

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  Students should understand how these processes allow a high degree of accuracy in copying base sequences.
  

• D1.1.3

  Role of helicase and DNA polymerase in DNA replication

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  Limit to the role of helicase in unwinding and breaking hydrogen bonds between DNA strands and the general role of DNA polymerase.
  

• D1.1.4

  Polymerase chain reaction and gel electrophoresis as tools for amplifying and separating DNA

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  Students should understand the use of primers, temperature changes and Taq polymerase in the polymerase chain reaction (PCR) and the basis of separation of DNA fragments in gel electrophoresis.
  

• D1.1.5

  Applications of polymerase chain reaction and gel electrophoresis
  

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  Students should appreciate the broad range of applications, including DNA profiling for paternity and forensic investigations.
  NOS: Reliability is enhanced by increasing the number of measurements in an experiment or test. In DNA profiling, increasing the number of markers used reduces the probability of a false match.
  

AHL Content Statements

• D1.1.6

  Directionality of DNA polymerases
  

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  Students should understand the difference between the 5' and 3' terminals of strands of nucleotides and that DNA polymerases add the 5' of a DNA nucleotide to the 3' end of a strand of nucleotides.
  

• D1.1.7

  Differences between replication on the leading strand and the lagging strand

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  Include the terms “continuous”, “discontinuous” and “Okazaki fragments”. Students should know that replication has to be initiated with RNA primer only once on the leading strand but repeatedly on the lagging strand.
  

• D1.1.8

  Functions of DNA primase, DNA polymerase I, DNA polymerase III and DNA ligase in replication

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  Limit to the prokaryotic system.
  

• D1.1.9

  DNA proofreading

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  Limit to the action of DNA polymerase III in removing any nucleotide from the 3' terminal with a mismatched base, followed by replacement with a correctly matched nucleotide.