DNA to PROTEIN
CHAPTER 12
 DEOXYRIBONUCLEIC ACID
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?
How are DNA and RNA similar?
 DNA is composed of nucleotides and RNA is
composed of nucleotides
How are DNA and RNA different?
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
DNA Replication
 Set up your DNA by applying the base pair
rules
Strand 1
A
T
C
G
G
Complementary Strand 2
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
PARTNER PRACTICE
 Person one uses their nucleotides as free
nucleotides
 Person two works with partner to replicate
their original strand

Discuss the enzymes as you model the
process
Do # 9 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
Figure 12–7 Structure of DNA
Section 12-1
Nucleotide
Hydrogen bonds
Sugar-phosphate
backbone
Key
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
Use your text to complete the diagram
and provide written details for the
process shown
Homework
 Complete labeling of notes cover
 Complete DNA replication labeling and
details
 Complete Section 10-1 Review – accuracy!
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
(DNA to mRNA)
Translation
(mRNA – tRNA to protein)
Concept Map
Section 12-3
RNA
can be
Messenger RNA
also called
Ribosomal RNA
which functions to
mRNA
Carry instructions
also called
which functions to
rRNA
Combine
with proteins
from
to
to make up
DNA
Ribosome
Ribosomes
Transfer RNA
also called
which functions to
tRNA
Bring
amino acids to
ribosome
Transcription
 #8 RNA polymerase reads one of the DNA
strands and makes a complementary mRNA
 #10 transcription details



Occurs in the nucleus
The gene sequence on DNA gets transcribed
Promoter region on DNA marks where
transcription should start and terminator region
marks where it should stop
mRNA
 RNA polymerase – key enzyme
 mRNA is a “copy” of the gene sequence and
can leave the nucleus
 mRNA finds its way to a ribosme and the next
step in making a protein can occur TRANSLATION
CLICK ON
PICTURE FOR
ANIMATION ON
TRANSCRIPTION
mRNA
 No T (thymine) so when it reads the
nucleotide A on DNA it matches it with ____?
 Do #11 in notes
#12 – TRANSLATION and 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
Copy down this DNA sequence
CAG GTG AAT TGG GGC CTC CAC TTT
 This is the template strand of DNA, complete
the complementary strand sequence below
the template.
 TRANSCRIPTION: read the template DNA
strand and write the complementary mRNA
 TRANSLATION: based on your mRNA,
determine the proper amino acid sequence
Copy this DNA sequence down
CAG GTG AAT TGG GGC CAC CAC TTT
REPEAT ALL THE STEPS AND DETERMINE THE
AMINO ACID SEQUENCE FOR THIS GENE!
COMPARE: what is the mistake?
 CAG GTG AAT TGG GGC CTC CAC
TTT
 CAG GTG AAT TGG GGC CAC CAC
TTT
One incorrect amino acid
GENOTYPE to PHENOTYPE
Figure 12–20 Chromosomal
Mutations
Section 12-4
Deletion
Duplication
Inversion
Translocation
Let’s Review
 DNA Structure is a _____ ______
 DNA is composed of __________
What are four that make up DNA?




A
T
C
G
Figure 12–5 DNA
Nucleotides
Section 12-1
Purines
Adenine
Guanine
Phosphate
group
Pyrimidines
Cytosine
Thymine
Deoxyribose
Figure 12–7 Structure of DNA
Section 12-1
Nucleotide
Hydrogen bonds
Sugar-phosphate
backbone
Key
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
Use your text to complete the diagram
and provide written details for the
process shown
Concept Map
Section 12-3
RNA
can be
Messenger RNA
also called
Ribosomal RNA
which functions to
mRNA
Carry instructions
also called
which functions to
rRNA
Combine
with proteins
from
to
to make up
DNA
Ribosome
Ribosomes
Transfer RNA
also called
which functions to
tRNA
Bring
amino acids to
ribosome
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