7.1 DNA structure and replication

IB Syllabus Statements

Understandings:

Nucleosomes help to supercoil the DNA.
DNA structure suggested a mechanism for DNA replication.
DNA polymerases can only add nucleotides to the 3’ end of a primer.
DNA replication is continuous on the leading strand and discontinuous on the lagging strand.
DNA replication is carried out by a complex system of enzymes.
Some regions of DNA do not code for proteins but have other important functions.

Applications and skills:

Application: Rosalind Franklin’s and Maurice Wilkins’ investigation of DNA structure by X-ray diffraction.
Application: Use of nucleotides containing dideoxyribonucleic acid to stop DNA replication in preparation of samples for base sequencing.
Application: Tandem repeats are used in DNA profiling.
Skill: Analysis of results of the Hershey and Chase experiment providing evidence that DNA is the genetic material.
Skill: Utilization of molecular visualization software to analyse the association between protein and DNA within a nucleosome.

Explain how the structure of DNA makes it ideally suited to its function.
Outline how Rosalind Franklin’s X-Ray diffraction provided evidence that DNA is a double helix.
Outline how nucleosomes help DNA to supercoil.
Outline how the structure of DNA could suggest a mechanism for DNA replication.
What is meant by the statement “DNA polymerases can only add nucleotides to the 3’ end of a primer”?
Distinguish between DNA replication on the leading strand and the lagging strand.
Explain the roles of the different enzymes and protein involved in DNA replication in prokaryotes. Include helicase, DNA gyrase, single strand binding proteins, DNA primase, DNA polymerase I, and DNA polymerase III.
Outline some of the functions of DNA that does NOT code for proteins. Include regulators of gene expression, introns, telomeres and genes for tRNAs.
Outline Rosalind Franklin’s and Maurice Wilkin’s investigation of DNA structure by X-Ray diffraction.
Explain how nucleotides containing dideoxyribonucleic acid are used to stop DNA replication in preparation of samples for base sequencing (Sanger sequencing).
Outline why tandem repeats are used in DNA profiling.
Explain the results of the Hershey and Chase experiment that provided evidence that DNA is the genetic material.
Explain how molecular visualization software can be used to analyse the association between protein and DNA within a nucleosome.