Essential Idea
The structure of DNA allows efficient storage of genetic information.
Understandings
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
Crick and Watson’s elucidation of the structure of DNA using model making.
Skills
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.
Key Vocabulary
Nucleic acid
Deoxyribonucleic acid (DNA)
Ribonucleic acid (RNA)
Nucleotide
Nitrogenous base
Sugar (Deoxyribose or Ribose)
Phosphate
Helix
Antiparallel
Textbook Reading and/or Activities
Click HERE for a pdf of chapter 2.
Pages XYZ
Nature of Science (p. XYZ)
Challenge Yourself (p. XYZ)
Worked Example (p. XYZ)
Notes
A detailed set of notes, prepared by Bob Smullen, examining all of the IB learning expectations.
i-Biology Notes (Not available)
A detailed set of notes, prepared by Stephen Taylor, examining U1 - U8 and A1 - A4.
A series of questions, prepared by Stephen Taylor, to help check your understanding of DNA replication. This is VERY GOOD practice.
A detailed set of notes, created by Chris Paine, examining all of the IB learning expectations.
A series of questions, created by Chris Paine, to help check your understanding of the IB learning expectations. This is VERY GOOD practice.
A detailed set of notes, prepared by Jacob Cedarbaum, examining U1 - U3 and A1 (slides 1-17), of the IB learning expectations.
2.6 Study Questions (NEW Syllabus)
A series of questions, prepared by Jacob Cedarbaum, to help check your understanding of the IB learning expectations. This is VERY GOOD practice. Answers (OLD).
Outlines the structure and function of DNA and RNA.
Learning Activities
Molecular Workbench - Proteins & DNA
An interactive online module enabling you to explore the structure and function of nucleic acids. Only review the nucleic acids section (p.7-12). Trouble using the module? Use these screen shots to see what you're missing.
A detailed animation, produced by John Kyrk, outlining the molecular structure of DNA and its relevant properties.
Supplemental Reading
Title
Description
This video outlines the process by which Watson and Crick were able to determine the structure of the DNA double helix. It includes the contributions of a number of other scientists at the time (Franklin, Chargaff and Pauling), each of whom were trying to solve the same mystery.
This alternative (silly) video describes the similarities and differences between DNA and RNA in a way that is simple to understand.
Should Watch Videos
This video describes the molecular structure of DNA and RNA examining similarities and differences. It also examines the process by which DNA is copied and is used to guide the production of proteins.
This video outlines and compares the molecular structure of the most common nucleic acids.
Must Watch Videos