LS: I will be able to distinguish the difference between DNA
and RNA.
LS: I will be able to explain the historical process of the
discovery of DNA.
Types of Nucleic Acids
Ribonucleic Acid
(RNA)—Single Stranded
Deoxyribonucleic Acid
(DNA)—Double Stranded
Main Goal
To store genetic information that will
eventually be translated into a protein
What is a
Nucleotide?
3 Parts of a nucleotide:
 Nitrogen base
 5 carbon
sugar(deoxyribose/ribose)
 Phosphate Group
The basic building blocks
for DNA or RNA
Nucleotides
There are 4 nitrogen bases making up 4 different nucleotides
Purines
Adenine
Guanine
Thymine
Pyrimidines
Cytosine
Contributors to the
Discovery of DNA
Rosalind Franklin never truly received the credit she deserved.
She was the first to use X-Ray diffraction to produce an image of
a DNA molecule, which implied a helix shape and the shape
depended on the level of hydration.
Erwin Chargaff created Chargaff's Rule: DNA will have an equal
number of guanines and cytosines because they bond together, as
is true for adenine and thymine. This led to his suggestion that
nitrogen bases paired “Complimentary” to one another.
Watson and Crick are famous due to winning
the Nobel Prize in 1962 for putting together all
of the data collected to show the final structure
of DNA—a double helix
More on Chargaff's Rules
DNA contains the same
amount of adenosine as
thymine
DNA contains the same
amount of cytosine as
guanine
What does this imply about the nitrogen bases
and how they bond?
DNA is like a _________
ladder…called a Double Helix.
The sides are alternating
sugar and phosphate groups
The rungs are the nitrogen
bases.
A always forms a double
Hydrogen bond with T
G always forms a triple
Hydrogen bond with C
The relationship of DNA, Genes,
and Chromosomes
https://www.youtube.com/watch?v=hT1XnGk6Wc
RNA compared to DNA
https://www.youtube.com/watch?v=0ElozX1k8M
What is RNA?
A helper molecule of DNA
Have the ability to leave the nucleus
RNA stands for RiboNucleic Acid,
and its sugar is Ribose
RNA is single stranded
RNA uses Uracil (U) instead of the base
Thymine (T)
What are the bonding rules for the
RNA bases?
When nitrogen bases pair together it is called
Complimentary Base Pairing.
DNA Sample Strand:
T A C C G C T A C C A T
What will the complimentary strand of DNA be?
What will the complimentary strand of RNA be?
What differences and similarities have you discovered about
DNA and RNA?
Compare and Contrast them in the Venn Diagram below:
DNA
RNA
Check your Understanding…
1. Another name for Ribonucleic Acid: ________
2. Another name for Deoxyribonucleic Acid: ______
3. In DNA Adenine always pairs with _______?
4. In both DNA and RNA Guanine always pairs with
_______?
5. In RNA adenine pairs with _______?
6. In both DNA and RNA, the backbone of the
molecules is made up of ________ and _______.