DNA/RNA
DNA
RNA
Watson & Crick
Maurice Wilkins & Rosalind Franklin
 Rosalind Franklin
Chargaff’s Rule of Ratios
From analytic studies Edwin Chargaff
(1952) determined that the:
 Amount of Adenine always equals
the amount of Thymine
 Amount of Cytosine always
equals the amount of Guanine
 The amount of A-T is independent
of the amount of C-G
Erwin Chargaff, an American biochemist
DNA: replication and protein
synthesis
Where have we seen DNA being
replicated?
MITOSIS
AND
MEIOSIS
Building blocks of DNA: Nucleotides
The sugar
Deoxyribose
The phosphate
The nitrogenous bases
The Purines
Why are these called nitrogenous bases?
The nitrogenous bases
The Pyrimidines
How are the pyrimidines different from the
purines?
Four different Nucleotides
BASIC
STRUCTURE
DNA is a polymer formed by base
pairing: Base pairing rule
The Double Helix
A. The overall shape of DNA is described as a double
helix (a twisted ladder).
B. What force holds the two strands together?
DNA Nucleotides
Section 12-1
Purines
Adenine
Guanine
Phosphate
group
Pyrimidines
Cytosine
Thymine
Deoxyribose
DNA Replication
 ANIMATION
 ANIMATION DETAILED
Enzymes involved in DNA replication
 Helicase – opens the double helix to allow for
replication
 DNA polymerase – reads the original DNA
strand and lays down complementary bases
 Ligase – glues the newly formed DNA
together
DNA replication practice
 You are DNA polymerase. Helicase has opened the
DNA strand – read each side and produce the
complementary copies.
__________________________________
AGGTAACCGGTTACGATTAT
TCCATTGGCCAATGCTAATA
AGGTAACCGGTTACGATTAT
TCCATTGGCCAATGCTAATA
12.2 (part 2) - The Structure of DNA
 Solving the Structure of DNA
 Three scientists who worked to solve the structure of DNA were
Rosalind Franklin, James Watson, and Francis Crick. Franklin
found clues. These clues helped Watson and Crick explain the
structure and properties of DNA.
12.2 (part 2) - The Structure of DNA
 A Venn diagram is made up of overlapping circles. It is a useful
tool for comparing two or even three topics. In the space where
the circles overlap, write the features that the topics share. In
the space where the circles do not overlap, write the features
that are unique to each topic.





built a three-dimensional model of DNA
helped determine the shape of a DNA molecule
photographed DNA using X-ray diffraction
showed that DNA is a double helix
studied DNA’s structure and properties
12.2 (part 2) - The Structure of DNA
 Complete the Venn diagram using phrases
from the word box.
photographed DNA
using X-ray
diffraction
- studied DNA’s
structure and
properties
helped determine
the shape of a DNA
molecule
showed that DNA is
a double helix
built a threedimensional model of
DNA
How are DNA and RNA similar?
 DNA is composed of nucleotides and RNA is
composed of nucleotides
IN YOUR NOTES TO PRACTICE
BASE PAIRING RULES AGAIN
__________________________________
A G T C C G T T A G T
T C A G G C A A T C A
Let’s Review
 DNA Structure is a _____ ______
 DNA is composed of __________
What are four that make up DNA?




A
T
C
G
How are DNA and RNA different?
 DNA…
 Nucleotides = deoxyribose sugar
 Double helix structure
 Stays inside nucleus
 RNA…
 Nuleotides = ribose sugar
 Single-strand structure
 Located both inside and outside of nucleus
 Uracil instead of thymine
How are DNA and RNA different?
Transcription
 mRNA – stands for messenger RNA



it is the copy of the DNA message for making
a protein
Occurs in the nucleus
Promoter region on DNA marks where
transcription should start and terminator region
marks where it should stop
mRNA
 Transcribes DNA message and carries it to
ribosome
 RNA polymerse is the enzyme that produces
it
CLICK ON
PICTURE FOR
ANIMATION ON
TRANSCRIPTION
mRNA
 No T (thymine) so when it reads the
nucleotide A on DNA it matches it with ____?
Protein Synthesis= transcription and
translation
 DNA contains all the information for your
traits – the genes
 These genes are blueprints and need to
remain safe – kept inside the nucleus
 Copies can be made though – a messenger
Genotype  Phenotype
DNA mRNA tRNA PROTEIN
Transcription
Translation
tRNA
 Once mRNA is made it attaches to a
ribosome
 tRNA = transfer RNA and they carry amino
acids
 Amino acids are the building blocks of
proteins (remember?)
Translation
 Ribosomes are the site of protein synthesis
 Click here to see mRNA and tRNA work
together at that ribosome to build a protein
Codon = mRNA
Anti-codon = tRNA
Comparing RNA & DNA
DNA
Nucleotide
Deoxyribose
RNA
X
X
Ribose
X
Single-stranded
Double-stranded
Nitrogenous
bases
X
X
X
X
X
Comparing RNA & DNA
DNA
Thymine
RNA
X
Uracil
Template for synthesis of
nucleic acid
Double helix
Replication
Transcription
X
X
X
X
X
X
Comparing RNA & DNA
DNA
RNA
Exact Copy
X
Messenger
More Than 1
Form
Found in
Nucleus
X
X
X
Leaves Nucleus
X
X
Does not Leave
X
Figure 12–7 Structure of DNA
Section 12-1
Nucleotide
Hydrogen bonds
Sugar-phosphate
backbone
Key
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
Figure 12–14 Transcription
Section 12-3
Adenine (DNA and RNA)
Cystosine (DNA and RNA)
Guanine(DNA and RNA)
Thymine (DNA only)
Uracil (RNA only)
RNA
polymerase
DNA
RNA
Do Now
Begin - RNA Concept Map
can be
also called
which functions to
from
also called
to
which functions to
to make up
also called
which functions to
RNA Concept Map
RNA
can be
mRNA
rRNA
also called
which functions to
Messenger
RNA
Carry instructions
from
DNA
also called
Ribosomal
RNA
tRNA
which functions to
also called
which functions to
Combine with
protein
Transfer RNA
Brings amino acids
to the ribosome
to
to make up
Ribosomes
Ribosomes
Chromosomal Mutations
Deletion
Duplication
Inversion
Translocation