Chapter 10
DNA, RNA, and
Protein Synthesis
S U B T ITLE
10.1 Discovery of DNA
10.1 Discovery of DNA
LEARNING TARGETS
I will be able to:
• Relate how Frederick Griffith’s experiment showed how a hereditary
factor was involved in transformation
• Summarize how Oswald Avery’s experiment concluded that DNA is
responsible for transformation in bacteria
• Describe how Hershey and Chase’s experiment led to the conclusion
that DNA is the hereditary molecule in viruses
Frederick Griffith (1928)
I
science!
Frederick Griffith (1928)
• British
• Studied Streptococcus
pneumonia
Frederick Griffith (1928)
• Tried to create a vaccine
• Studied 2 strains:
• R strain – does not cause
pneumonia
• S strain – causes pneumonia
Frederick Griffith (1928)
• What does this image show?
Frederick Griffith (1928)
• Griffith concluded that the
heat killed S cells released
their genetic material to
the R cells
• transformation
• R cells became diseasecausing
Oswald Avery (1940’s)
• American
I
smores…..and
science!!
Oswald Avery (1940’s)
• Wanted to know if DNA, RNA, or protein was responsible
for transformation in Griffith’s experiment
Oswald Avery (1940’s)
• Wanted to know if DNA, RNA, or protein was responsible
for transformation in Griffith’s experiment
Oswald Avery (1940’s)
• 3 experiments
• Found out that when
DNA wasn’t present,
S cells couldn’t
transform R cells
Oswald Avery (1940’s)
Hershey and Chase (1952)
Hershey and Chase (1952)
Hershey and Chase (1952)
• American
• Determined that DNA is the hereditary molecule in viruses
Hershey and Chase (1952)
10.2 DNA Structure
10.2 DNA Structure
LEARNING TARGETS
I will be able to:
• Evaluate the contributions of Franklin and Wilkins in helping Watson
and Crick discover DNA’s double helix structure
• Describe the 3 parts of a nucleotide
• Relate the role of base-pairing rules to the structure of DNA
Rosalind Franklin and Maurice Wilkins
Rosalind Franklin and Maurice Wilkins
• Took x-ray diffraction photos of DNA crystals
• This information was then used by Watson and Crick
James Watson and Francis Crick (1953)
• Watson (American) & Crick
(British)
• Developed double helix model of
DNA structure
• Looks like a twisting staircase
James Watson and Francis Crick
• Howard Wolowitz (American)
DNA Nucleotides
• Nucleotides are the building
blocks (monomers) of ………?
DNA Nucleotides
• Nucleotides are the building
blocks (monomers) of ………?
• NUCLEIC ACIDS!!!!!!!!!!!
• If answered correctly…
https://www.youtube.com/watch
?v=3GwjfUFyY6M
DNA Nucleotides (3 parts)
• Made up of 3 parts:
1. 5 carbon sugar (deoxyribose)
2. Phosphate group
3. Nitrogenous base
• Sugar and phosphate groups are
identical in all nucleotides
• Bases are different
Nitrogenous Bases (4 types)
1. Thymine (T)
2. Cytosine (C)
• These are pyrimidines
• pyrimidines – have only 1 carbon
ring
3. Guanine (G)
4. Adenine (A)
• These are purines
• Purines – have 2 carbon rings
Erwin Chargaff (1949)
• American biochemist
• Noticed that amount of A =
amount of T
• Amount of C = amount of G
• This led to base-pairing rules
Base-Pairing Rules
• C always pairs with G
• A always pairs with T
• These are complementary
bases
• connected by hydrogen bonds
Base-Pairing Rules
Base-Pairing Rules
10.3 DNA Replication
10.3 DNA Replication
LEARNING TARGETS
I will be able to:
• Summarize the process of DNA replication
• Identify the role of enzymes if the replication of DNA
• Describe how complementary base pairing guides DNA replication
• Describe mutations that occur during DNA replication
10.3 DNA Replication
https://www.youtube.com/watch?v=dKubyIRiN84
DNA Replication
• Amount of DNA is
doubled in
preparation for cell
division
DNA Replication – 3 Steps
1. One DNA strand is
separated into two
strands
• Helicases – enzymes that
separate DNA strands
• What kind of bond is
being broken here?
DNA Replication – 3 Steps
1. One DNA strand is
separated into two
strands
• Helicases – enzymes that
separate DNA strands
• Almost like using a zipper
on a jacket
• Y shaped region where
strands are being
separated is called
replication fork
DNA Replication – 3 Steps
2. Complementary bases
are added to new
strands
• DNA polymerase –
enzyme that adds
nucleotides to new
strands
DNA Replication – 3 Steps
3. DNA polymerase falls
off
• Forms two new strands
Mutations
• Mutation – change in
nucleotide sequence of
DNA
Mutations
• Point Mutation – one
single nucleotide is
altered by addition,
subtraction, or deletion
• Addition – nucleotide is
added to the sequence
Mutations
• Point Mutation – one
single nucleotide is
altered by addition,
subtraction, or deletion
• Deletion – one nucleotide
is removed from sequence
Mutations
• Point Mutation – one
single nucleotide is
altered by addition,
substitution, or deletion
• Substitution – one
nucleotide is exchanged
for another
10.4 Protein Synthesis
10.4 Protein Synthesis
LEARNING TARGETS:
I will be able to:
• Outline the flow of genetic information from DNA to protein
• Compare the structures of DNA and RNA
• Summarize the process of transcription
• Compare the role of mRNA, tRNA, and rRNA
• Identify the importance of learning about the human genome
10.4 Protein Synthesis
https://www.youtube.com/watch?v=41_Ne5mS2ls
Protein Synthesis Overview
•Consists of transcription
and translation
•Transcription – info
transferred from DNA to
RNA
•Translation – RNA directs
assembly of proteins
RNA Structure
•single chain
•Sugar = ribose (not
deoxyribose)
•Has uracil (U) instead of
thymine (T)
•U-A and C-G base pairing
3 Types of RNA
1. mRNA – messenger
RNA
• Takes info from DNA in
nucleus to ribosome in
cytosol
3 Types of RNA
2. tRNA – transfer RNA
• Transfers amino acids
during translation
3 Types of RNA
3. rRNA – ribosomal
RNA
• Makes up part of the
ribosome
Transcription Steps
1. RNA polymerase
attaches to promoter
• Promoter – specific
sequence of
nucleotides where RNA
knows to attach
• what type of molecule
is RNA polymerase?
Transcription Steps
2. DNA unwinds
Transcription Steps
3. RNA polymerase
reaches termination
signal, and breaks off
• Complementary mRNA
is formed!
Transcription Steps
Worksheet 10.4 #1
DNA: T T A C G T C A C
RNA: ?
Transcription Steps
Worksheet 10.4 #1
DNA: T T A C G T C A C
RNA: A A U G C A G U G
Genetic Code
• Explains how a sequence of bases creates a specific
amino acid
Genetic Code
• 3 nucleotides (letters) codes for a specific amino acid (word)
• Codon – a 3 nucleotide (letter) sequence in mRNA that codes
for an amino acid
Codon Table
Codon Table
Translation Steps
1. mRNA attaches to
rRNA of ribosome
2. tRNA brings amino
acids to ribosome
• Don’t forget that amino
acids are the building
blocks of proteins!
• Anticodon on tRNA
starts the translation
process
Translation Steps
• Codon =
CGA
• Anticodon = GCU
Translation Steps
3. tRNA keeps bringing
amino acids to
ribosome
Translation Steps
4. Amino acids form
peptide bond
together
5. tRNA leaves
Translation Steps
6. Stop codon reached
and translation stops
7. Ribosome leaves and
protein forms
Translation Steps
Worksheet 10.4 #3
mRNA = A A U G C A G U G
Amino acids = ?
Translation Steps
Worksheet 10.4 #3
mRNA = A A U G C A G U G
Amino acids = asparagine alanine valine
Translation Steps
https://www.youtube.com/watch?v=B6O6uRb1D38
Human Genome
• We’ve figured out the order of 3.2 billion base pairs
in the 23 human chromosomes!!!!!!!!!!!!!!
• About 30,000 genes in human genome
• Can help find genes responsible for specific diseases
Bellwork
Answer the following questions:
What are the roles of helicase and DNA polymerase
during DNA replication?
What are the three parts of a nucleotide?
Write the complementary base pairs to
ATCCAGGACTA.