Guided notes covering material from Topics 2.6 and 7.1 of the updated IB Biology syllabus for 2016 exams. Notes sequence and prompts are based on the Oxford IB Biology textbook by Allott and Mindorff.

1. IB Biology Chapter 2 Notes: Structure of DNA & RNA (2.6 & 7.1)NAME:
Word Definition
Nucleotide A monomer of DNA made of sugar, phosphate and nitrogen base
Deoxyribose The sugar that is in DNA. It is a five carbon sugar that forms a ring
Ribose The sugar that is in RNA. It is a five carbon sugar that forms a ring
Complementary When things match or go together. In DNA this refers to bases that bond together
on opposite strands of DNA. (C-G, A-T)
Antiparallel A term to describe how opposite sides of the DNA molecule run in opposite
directions (3’-5’ vs 5’-3’)
3’ (prime) The third carbon on the deoxyribose molecule.
5’ (prime) The fifth carbon on the deoxyribose molecule
Histone A protein that DNA is wrapped around
Nucleosome A unit of DNA/protein structure composed of 8 histones with DNA wrapped around
them.
Purines Large nitrogen bases found in DNA (double carbon ring); Adenine and Guanine
Pyrimidines Small nitrogen bases found in DNA (single carbon ring); Cytosine and Thymine
Nitrogen bases One part of a nucleotide. This is the variable part (adenine, thymine, cytosine, and
guanine)

2. 2.6.1 The nucleic acids DNA
and RNA are polymers of
nucleotides.
2.6.2 DNA differs from
RNA in the number of
strands normally present,the
base composition, and the
type of pentose.
2.6.5 Draw simple diagrams
of the structure of single
nucleotides and of DNA and
RNA, using circles,
pentagons,and rectangles to
represent phosphates,
pentoses,and bases.
2.6.3 DNA is a double helix
made of two antiparallel
strands of nucleotides linked
by hydrogen bonding
between complimentary base
pairs.
2.6.4 Crick and Watson’s
elucidation of the structure
of DNA using model-
making.
Label the simplified nucleotide:
What types of bonds link nucleotides?
How many different types of nucleotides are in DNA?
DNA RNA
Type of Pentose
sugar
Number of
strands
Nitrogen bases
Draw diagrams of DNA and RNA molecules:
DNA: RNA:
Outline the structure of the DNA molecule:




What were problems in Watson & Crick’s first model?
What were important revisions in the final model?

3. 7.1.2 Nucleosomes help to
supercoil the DNA.
7.1.11 Utilize molecular
visualization software to
analyze the association
between protein and DNA
within a nucleosome.
7.1.6 Some regions of DNA
do not code for proteins but
have otherimportant
functions.
7.1.7 Discuss Rosalind
Franklin’s and Maurice
Wilkins’ investigation of
DNA structure by X-ray
diffraction.
7.1.10 Analysis of results of
the Hershey and Chase
experiment providing
evidence that DNA is the
genetic material.
Describe the nucleosome structure:
What is ‘supercoiling?’
Highly-repetitive sequences:
What are ‘telomeres?’
How did Franklin and Wilkins visualize DNA structure?
What conclusions did they make based on their photograph?
Why did scientists initially think protein was the genetic material?
What type of virus did Hershey and Chase use and why?
How did Hershey and Chase determine DNA, not protein, was the genetic material?