DNA and RNA StructureUnderstandings:
• The nucleic acids DNA and RNA are polymers of nucleotides. • DNA differs from RNA in the number of strands present, the base composition and the type of pentose. • DNA is a double helix made of two antiparallel strands of nucleotides linked by hydrogen bonding between complementary base pairs. |
|
Applications and skills:
• Application: Crick and Watson’s elucidation of the structure of DNA using model making.
• Skill: Drawing simple diagrams of the structure of single nucleotides of DNA and RNA, using circles, pentagons and rectangles to represent phosphates, pentoses and bases.
Guidance:
• In diagrams of DNA structure, the helical shape does not need to be shown, but the two strands should be shown antiparallel. Adenine should be shown paired with thymine and guanine with cytosine, but the relative lengths of the purine and pyrimidine bases do not need to be recalled, nor the numbers of hydrogen bonds between the base pairs.
• Application: Crick and Watson’s elucidation of the structure of DNA using model making.
• Skill: Drawing simple diagrams of the structure of single nucleotides of DNA and RNA, using circles, pentagons and rectangles to represent phosphates, pentoses and bases.
Guidance:
• In diagrams of DNA structure, the helical shape does not need to be shown, but the two strands should be shown antiparallel. Adenine should be shown paired with thymine and guanine with cytosine, but the relative lengths of the purine and pyrimidine bases do not need to be recalled, nor the numbers of hydrogen bonds between the base pairs.
|
|
Francis Crick, James Watson Rosalind Franklin, Maurice Wilkins
Application: Rosalind Franklin’s and Maurice Wilkins’ investigation of DNA structure by X-ray diffraction.
Martha Chase and Alfred Hershey
Skill: Analysis of results of the Hershey and Chase experiment providing evidence that DNA is the genetic material.
Skill: Analysis of results of the Hershey and Chase experiment providing evidence that DNA is the genetic material.
Controversy among the scientistsTheory of knowledge:
The story of the elucidation of the structure of DNA illustrates that cooperation and collaboration among scientists exists alongside competition between research groups. To what extent is research in secret ‘anti-scientific’? What is the relationship between shared and personal knowledge in the natural sciences? |
