Download Intro to DNA * Refresher Tasks

Intro to DNA – Refresher
Tasks
 Draw the structure of DNA.
 Identify the 4 base pairs found in DNA.
 List are the major differences between DNA &
RNA.
 Identify the chemical components of DNA.
 Identify the role DNA plays in our bodies.
Lesson Goals – Intro to DNA
 Identify and describe the chemical
components of DNA.
 Discuss the experiments leading to the
identification of DNA as the molecule that
carries genetic code.
 Describe the steps leading to the
development of the double – helix model of
DNA.
Chargaff’s rule
 Percentages of bases in five organisms:
Source of
DNA
A
T
G
C
Streptococcus
29.8
31.6
20.5
18.0
Yeast
31.3
32.9
18.7
17.1
Herring
27.8
27.5
22.2
22.6
Human
30.9
29.4
19.9
19.8
E.coli
24.7
23.6
26.0
25.7
 Analyze the data from Chargaff’s studies. What do you
notice about the ratio of base pairs between the vastly
different organisms?
 Use math: if an organism has 33% A bases, what does this
mean about the amount of G in the organisms genetic
sequence.
Assessment Questions
 List the chemical components of DNA.
 Why are hydrogen bonds so essential in the
structure of DNA?
 Describe the discoveries that led to the
modelling of DNA
 Describe Watson and Crick’s model of the
DNA molecule.
 Did Watson and Crick’s model account for the
equal amounts of thymine and adenine in
DNA? Explain.