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Goal 3.01b: Protein Synthesis
and Gene Regulation
Central Dogma
From Gene to Protein
Bodies  Cells  DNA
 Bodies are made up of cells
 All cells run on a set of instructions
spelled out in DNA
neveryetmelted.com
i.ivillage.com
…to be different heights?
What makes it possible for different people…
www.learnwell.org
… to have different faces?
www.saidaonline.com
…to have different colored eyes?
symonsez.files.wordpress.com
Those
proteins
give us our
looks.
Makes this protein…
Each DNA
makes a
specific
protein.
or this protein…
cr4.globalspec.com
or this protein!
gamespot.com
Remember…
 Bases match together
A pairs with T
A : T
 C pairs with G
C : G
 weak bonds
Now it is time to find out how DNA
between bases
manages to create so many different
join 2 strands
kinds of organisms using
 can separate easily
only FIVE pieces of information!

What do we know?
 DNA

DNA is the genetic information
 Proteins
proteins run living organisms
 enzymes

 all chemical reactions in living organisms are
controlled by enzymes (proteins)

structure
 all living organisms are built out of proteins
 DNA is the instructions for making proteins
What else do we know?
 DNA


DNA is in the nucleus
want to keep it there =
protected
 Proteins


made by a “protein
factory” in cytoplasm
ribosomes
 Need to get gene (DNA)
information from
nucleus to cytoplasm



need a messenger!
need a copy of DNA
mRNA
DNA
• deoxyribose sugar
• nitrogen bases
– G, C, A, T
• T = thymine
–T:A
–C:G
• double stranded
RNA
• ribose sugar
• nitrogen bases
– G, C, A, U
• U = uracil
–U:A
–C:G
• single stranded
A brief overview of what happens…
transcription
DNA
mRNA
protein
translation
trait
nucleus
cytoplasm
The problem with DNA…
DNA (double helix) is too big
to go through the pores in
the nuclear envelope.
RNA (single helix) is small.
DNA gives its information to
mRNA (messenger RNA) to
carry out of the nucleus.
TOO BIG!
Just right.
TRANSCRIPTION
• Making mRNA from DNA
• DNA strand is the
template (pattern)
– match bases
• U:A
• G:C
• Enzyme
– RNA polymerase
mRNA
TRANSCRIPTION
Making mRNA from DNA
T G G T A C A G C T A G T C A T CG T A C CG T
U
U
U
U
U
T G G T A C A G C T A G T C A T CG T A C CG T
TRANSCRIPTION
• Double stranded DNA unzips
T G G T A C A G C T A G T C A T CG T A C CG T
TRANSCRIPTION
Free-floating
nucleotides
• Use RNA polymerase
• Match free floating RNA
bases to DNA bases on one of
the DNA strands
AG
A
G
C
U
A
G
G
U
U
C
A
C
G
A
U
A
C
RNA
A C C polymerase G
A
U
T G G T A C A G C T A G T C A T CG T A C CG T
U
C
TRANSCRIPTION
We are transcribing DNA into RNA.
U instead of T is matched to A
DNA T A C G C A T T T A C G T A G C G G
l I I I I I I I I I I I I I I I I I
mRNA A U G C G U A A A U G C A U C G C C
Transcription Animation
http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/transcription.swf
What do we know NOW?
 DNA

instructions remain in nucleus
 mRNA

A C C A U G U C G A U C A GU A GC A U G GC A
has the instructions for building
proteins from DNA
 Proteins

built as chains of amino acids
 What reads RNA?
need a mRNA reader!
 rRNA in ribosomes

From gene to protein
CELL
cytoplasm
Transcription
Protein
Trait
aa
aa
DNA
Translation
aa
aa
aa
mRNA
aa
aa
nucleus
ribosome
A C C A U G U C G A U C A GU A GC A U GGC A
rRNA
mRNA leaves
nucleus through
nuclear pores
rRNA inside the ribosomes
synthesize amino acids to
make a protein using
instructions on mRNA
What do we ALSO know now?
 mRNA
ribosome
A C C A U G U C G A U C A G U A G C A U GaG C A

has the instructions for building proteins
from DNA
 Proteins

a
a
a
a
a
a
ribosome
What brings the right amino acid to attach to the
protein chain?
 need an amino acid transporter!


tRNA
a
Peptide bonds
built as chains of amino acids linked by
a
peptide bonds
 What reads mRNA?

a
a
a
From gene to protein
cytoplasm
Transcription
CELL
Protein
Trait
aa
aa
DNA
Translation
mRNA
nucleus
aa
aa
aa
aa
ribosome
A C C A U G U C G A U C A GU A GC A U GGC A
tRNA
aa
tRNA carries the correct
amino acid (based on the
mRNAcode) to the ribosome.
Let’s build a flow chart!
Protein Synthesis
TRANSCRIPTION
DNA gives mRNA blueprints for making a specific protein.
mRNA carries the blueprints out of the nucleus to the cytoplasm
and finds a ribosome.
TRANSLATION
rRNA reads the mRNA inside the ribosome.
tRNA brings the correct amino acid to the mRNA.
An amino acid chain is built: PROTEIN.
Protein give us our traits.
BUILD DNA AND DISCOVER GENES!
http://learn.genetics.utah.edu/content/begin/dna/
1. What is DNA?
2. What is a Gene?
3. Build a DNA Molecule.
How does tRNA know which
amino acid to bring?
• When mRNA leaves nucleus it has a blueprint
of DNA’s instructions.
• mRNA goes to ribosomes in cytoplasm
• Ribosomes read the blueprint on mRNA.
mRNA
ribosome
A C C A U G U C G A U C A GU A GC A U G GC A
aa
aa
aa
aa
aa
aa
aa
aa
Using the template…
DNA
TACGCACATTTACGTACGCGG
mRNA
AUGCGUGUAAAUGCAUGCGCC
?
protein
Met Arg Val Asn Ala Cys Ala
How can you code for 20 amino acids with only
4 nucleotide bases (A,U,G,C)?
mRNA codes for proteins in triplets
DNA
TACGCACATTTACGTACGCGG
Codon = set of 3 bases
mRNA
ribosome
AUGCGUGUAAAUGCAUGCGCC
AUGCGUGUAAAUGCAUGCGCC
UAC
Amino
acid
?
Anticodon = set of 3 bases
Met Arg Val Asn
Cys Ala
Ala
AUGcode is UNIVERSAL!
The
• Since all living
organisms…
– use the same DNA
– use the same code
book
– read their genes the
same way
What amino
acids are
coded for by
these
codons?
UGA
ACU
AAC
GAG
The mRNA code
• For ALL life!
– Uses only 4 bases for
ALL life. (strongest
support for a common
origin for all life)
• Code is redundant
– several codons for each
amino acid
– mutation insurance!
 Start codon


AUG
methionine
 Stop codons

UGA, UAA, UAG
mRNA
DNA
TACGCACATTTACGTACGCGG
AUGCGUGUAAAUGCAUGCGCC
Transcription and Translation Builder
http://learn.genetics.utah.edu/content/begin/dna/transcribe/
tRNA
tRNA
tRNA
Ala
tRNA
Arg
Pro
Val
Leu
Met
Transcription in Real Time (view as class) http://www.dnalc.org/resources/3d/TranscriptionBasic_withFX.htmll
Step Through Translation
http://bcs.whfreeman.com/thelifewire/content/chp12/1202003.html
You Transcribe and Translate a Gene!
http://learn.genetics.utah.edu/content/begin/dna/
1. Transcribe and Translate a Gene
2. What makes a firefly glow?
DNA Translation Real Time and Interactive
http://www.dnai.org/a/index.html
A Quick Review….
DNA
1. What is this molecule?
3.Whattranscription
is this process?
2.What is this molecule?
mRNA
amino
6.What
are
theseacids
molecules?
Can you tell
the story?
4.What is this
structure?
ribosome
5.What is this
protein
molecule?
7.What is this
tRNA
8.What istranslation
this process?
29:08 Central Dogma Biologix__Translation_and_Protein_Synthesis
molecule?
Substitution/Point Mutation = one base is changed and one
amino acid is changed.
DNA
TAC GCA TGG AAT  TAC GCA
T TGG AAT
mRNA
AUG CGU ACC UUA  AUG CAU ACC UUA
Protein
Met Arg Thr
Leu  Met
His
Thr Leu
Insertion Mutation = one base is inserted and everything
downstream is changed.
DNA
TAC CGT
GTA ATG
TGG GAA
AAT T
TAC GCA TGG AAT  TAT
mRNA
AUG CGU ACC UUA  AUA GCA UAC CUU A
Protein
Met Arg Thr
Leu  Ile
Ala
Tyr Leu
http://highered.mcgraw-hill.com/sites/0072556781/student_view0/chapter11/animation_quiz_4.html
EXPLAIN DIVERSITY…
• Each organism has a unique sequence of DNA.
• The DNA sequence determines the order of amino
acids in the organism’s proteins.
• The order of amino acids determines the shape that
the protein made will take.
• The shape of the protein determines what it can do.
• What the protein does determines everything about
the organism.
• Gene Regulation determines when a sequence of DNA
will be put to use and when it won’t.
Gene Regulation…Keeping Control!
Every species has
its own number of
chromosomes in
each cell.
Notice:
More is not always
better... Sometimes
it’s just more.
Organism
Number of
Chromosomes
Cat
32
Chimpanzee
48
Dog
78
Cow
60
Human
46
Horse
64
Pea plant
14
Corn plant
20
Mosquito
6
Honeybee
32
Sugarcane
80
Sand dollar
62
Remember…a section on a
chromosome that codes for a
specific trait is called a GENE.
And…
There are lots and lots of
genes on each chromosome!
The job of a gene is to control
the production of proteins.
Not every gene is expressed
(turned on) at the same time.
Gene Regulation = what
controls when a gene is
expressed and when it is not.
In bacteria, genes are in groups
called Operons.
Example: E. coli that’s in our
digestive system helps us
break down milk.
Baby features (birth – 5 yrs)
Teen features (12 yrs – 17 yrs)
Adult features (17 yrs – 60 yrs)
Child features (5 yrs – 12 yrs)
Elderly features (60 yrs – death)
Each Operon codes for a
specific protein.
Start Codon = set of
three nucleotide bases
where transcription
begins.
Stop Codon = set of
three nucleotide bases
where transcription
ends.
RNA
polymerase
3’
5’
Promoter Sequence =
area “upstream”
(toward the 5’ end)
from the gene where
the RNA polymerase
attaches.
Terminator Sequence
= area “downstream”
from the gene where
the polymerase
detaches.
Has to have a CAP to start.
Are You Lactose
Intolerant?
Here’s how we
metabolize
milk…
Lac operon
http://sumanasinc.com
/webcontent/animation
s/content/lacoperon.ht
ml
Can NOT have a Repressor.
Beadle and Tatum
One gene, one protein.
Beadle and Tatum Experiment
http://wps.prenhall.com/wps/media/objects/1552/1589869/web_tut/21_04/21_04_01a.swf
Gene Therapy: Introduction
What is Gene Therapy?
Using parts of a gene from a healthy cell to fix a
damaged or sick cell.
How
Gene Therapy
Works
(Interactive)
http://www.edu365.cat/aul
anet/comsoc/Lab_bio/sim
ulacions/GeneTherapy/Ge
neTherapy.htm
Don’t hate me
Blame
it on
because
I’mmy
Any
GENES!
beautiful…
Questions?
Assignment:
Coach Book L15
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