“DNA to Protein” Unit Notes
Review from 10.1 (pg. 185): DNA
Objectives:
 Explain the principal function of DNA
 Describe the structure of DNA
 Define complementary base pairing
 Explain the role of complementary base pairing in the replication of DNA
 Summarize the main features of DNA replication
“What is a Gene?” Animation
DNA codes for genes.
What is a gene?
About how many genes do
humans have?
How many of these genes code
for making hemoglobin? What is
hemoglobin?
What can happen if a gene is
mutated?
Give an example of a mutated
hemoglobin gene. What do these
red blood cells look like with this
mutated gene?
“What is a Protein?” Animation
What is a protein?
Thousands of different proteins that work together to perform the
specific job of the cell.
Every cell contains…
Ex: Bone cells have proteins that function together to make the cell a
bone cell!
“Anatomy of a Gene” Website
The shortest gene in humans is
______ nucleotides and the longest
gene is _____ nucleotides.
Shortest:
Longest:
What percent of our genome (all
our DNA) is made up of genes?
Some of our genome makes noncoding genes which do what?
Most of our genome does NOT
code for anything at all!!!
Why is this part of our genome
still important?
10.2 (pg. 190): RNA
Objectives:
 Explain the primary functions of RNA
 Compare the structure of RNA with that of DNA
 Describe the structure and function of each type of RNA
 Summarize the process of transcription
DNA is made up of
nucleotides consisting
of what 3 things?
DNA codes for genes
that contain the
information needed to
make what?
The genes on the DNA
are located where in
eukaryotes?
What are the building
blocks of proteins?
Amino acids are found
where in the cell?
Thus proteins must be
made where in the cell?
RNA is responsible
for…
RNA is made up of:
What is the full name
for RNA?
1.
How is RNA different in
structure from DNA?
2.
3.
**Why do you think
RNA can leave the
nucleus but DNA can’t?
1.
What are the 3 types of
RNA?
2,
3.
What does mRNA look
like and what does it
do?
What does tRNA look
like and what does it
do?
What does rRNA look
like and what does it
do?
Transcription
Promoter
RNA Polymerase
Termination Signal
Steps of Transcription:
What is the DNA
template?
In a eukaryote, how
many promoters are
there per gene?
1. RNA polymerase binds to the promoter and unwinds the DNA
2. RNA polymerase cuts the hydrogen bonds between the nitrogen
bases (A-T, C-G)
3. New nucleotides pair up (A-U, C-G)
4. RNA polymerase bonds the nucleotides together
5. A termination signal is reached and the new RNA strand is
released
DNA Strand:
RNA Strand:
ATCGGAAT
What gets made in
transcription (the
products)?
After the mRNA gets
made, where does it
go?
“Anatomy of a Gene”Website
Exon
Intron
Humans have on
average about how
many introns per gene?
(Not all genes have
introns, though)
mRNA splicing
What proteins control
the cutting out or
splicing of introns?
Homework:
Complete this on a separate sheet of paper in complete sentences. Don’t forget your
name!
1. Define transcription and list the main steps involved. Draw and label a picture to
help support your definition.
2. List the 3 roles of RNA polymerase in transcription. Compare this to the 3 enzymes
you learned about in DNA replication.
3. Create a Venn Diagram comparing and contrasting DNA and RNA.
4. Describe the structure and function of each of the 3 types of RNA.
5. Name the rule that ensures the transcribed RNA molecule is carrying the right
message/code.
6. Discuss why it matters which DNA chain in the double helix is used for
transcription.
10.3 (pg. 193): Protein Synthesis
Objectives:
 Describe the genetic code
 Distinguish between a codon and an anticodon, and state where each is found
 Explain the roles of the start codon and stop codons
 Summarize the process of translation
Protein Synthesis
The amount and type of
proteins in a cell
determine:
Proteins are polymers
made up of many
monomers. What are the
monomers or building
blocks of proteins?
Polypeptides
Proteins are also called:
Amino acids are joined
together by what bonds?
How many different
amino acids are there?
What does the sequence
of amino acids determine?
How can only 20 amino
acids code for thousands
of different proteins?
Codon
Each codon codes for a
specific…
How many possible
codons are there?
Start codon
Stop codon
They can be composed of 1 or more polypeptide chains.
Amino acid abbreviation:
What does GCU codon
represent?
Amino Acid name:
Amino acid abbreviation:
What does CGU
represent?
What does AUG
represent?
Translation
Where does translation
occur in the cytoplasm?
What carries amino acids
in the cytoplasm to the
ribosome?
Anticodon
Amino Acid name:
Amino acid abbreviation:
Amino Acid name:
Describe the pairing of
tRNA anticodon with the
mRNA codon.
What are ribosomes made
up of?
What do ribosomes do?
1.
What are the 3 binding
sites in ribosomes?
2.
3.
Transcribe the DNA
sequence:
TACTATCCGATT
Translate the mRNA
sequence
Steps of Translation
More than 1 ribosome can
translate a mRNA strand.
What is the distance apart
of the ribosomes?
1. mRNA leaves the nucleus and goes to the ribosome
2. INITIATION: ribosome subunits and a tRNA join together at the start
codon and begin reading the mRNA
3. ELONGATION:
 mRNA is read in groups of 3 called codons
 A message is sent to the tRNA to pick up an amino acid and
bring it to the ribosome
 The anticodon on the tRNA matches with the codon on the
mRNA and the tRNA drops off the amino acid
 The next codon moves in and the process is repeated
4. TERMINATION: stop codon is reached and the protein is released; the
ribosome complex falls apart
Homework:
Complete the questions on a separate piece of paper in complete sentences.
1. Compare and contrast transcription and translation in a Venn Diagram.
2. Distinguish a codon from an anticodon.
3. Describe the function of tRNA in translation.
4. Decipher the amino acids that are coded for by the codons AUG, AGU, CCU, and GUG.
5. Explain the significance of the start and stop codons. Do all polypeptides begin
with the Methionine (MET) amino acid?
6. Explain what translation of the mRNA transcript UAACAAGGAGCAUCC would produce.
Chapter 11:
Gene Expression
Gene Expression
Does every single cell
produce every single
possible protein? Why
or why not?
Why is gene expression
controlled?
Genome
Gene Expression in Prokaryotes
Prokaryotes do not have a
________ and are singlecelled organisms.
Lactose is a double-sugar
(disaccharide) made up of
which two single-sugar
molecules
(monosaccharides)?
Operon
What is the lac operon in
E. coli?
Structural genes
Promoter
Operator
When were the genes for
the enzymes responsible
for breaking down lactose
expressed (turned on)?
Repression
In the absence of lactose,
what attached to the
operator? What did it do
to the operon?
Activation
Inducer
When lactose is present in
the E. coli cell, what does
it do to the repressor
protein? How does this
affect the operon?
By controlling gene
expression…
E. coli conserves resources and produces only those proteins that are needed
Eukaryote Gene Expression
Why are eukaryotes more
complex than
prokaryotes?
Why is eukaryote gene
expression more
complex?
Tightly coiled DNA is
called heterochromatin.
Draw this with tightly
coiled DNA around
histone proteins.
Euchromatin:
Draw it:
Heterochromatin:
How does the degree to
which DNA is coiled affect
gene expression?
How can the pattern of
introns and exons code for
new protein structures?
What is pre-mRNA and
what happens to it before
translation?
Cell differentiation