Download Protein Synthesis

Warm-Up:
• Make a little chart like the one below & complete
Macromolecule
Nucleic Acid
Protein
Building
Block
Job in the
body
Protein Synthesis
AKA How do your genes determine your
traits?
3210.4.3
• Recognize the interactions between DNA and
RNA during protein synthesis.
Remember that Proteins:
• Speed up reactions
(enzymes) for
metabolism
• Build & repair
tissues
• Protect your body
So really…Proteins are what
determine all of your traits!
________________ are the building
blocks of proteins
The order of
these building
blocks
determines the
job of the
protein.
So….
If proteins make your body - they
must come from somewhere…
But what could possibly provide
enough instructions to make all of
them?
DNA is the genetic code
• The order of the
letters (A,T,C,G)
determines what
protein is made
(which determines
the trait)
• Every 3 bases
make a codon (the
code for one
amino acid)
DNA is decoded in a process
called protein synthesis.
The DNA instructions
are first turned into an
RNA copy and then
those instructions are
used to make a protein.
Where is DNA kept?
Where is protein made?
What is RNA?
• nucleic acid
• “disposable”
copy of DNA’s
instructions can leave the
nucleus!!!
DNA
• DeoxyriboNucleic Acid
• Sugar = Deoxyribose
RNA
• Ribonucleic Acid
• Sugar = Ribose
DNA
• A&T
• C&G
RNA
• A&U
• C&G
• (Uracil instead of
Thymine)
DNA
RNA
• Double Helix (twisted
ladder)
• Single Strand (looks
like ½ the ladder)
• Found only in the nucleus
(stays protected)
• Found in the nucleus, in
the cytoplasm and at
the ribosomes
DNA
• One strand can code for
thousands of genes
RNA
• one strand codes for
exactly one gene that
makes one protein
3 major types of RNA
tRNA
(transfer)
mRNA
(messenger)
rRNA
(ribosomal)
mRNA (messenger RNA)
• carries the DNA’s
instructions from
the nucleus to the
ribosome
• complementary to
the original DNA
(except Us instead
of Ts)
tRNA (transfer RNA)
• brings an amino acid to the
ribosome so the protein can
be put together
• has an anticodon on one
end (3 RNA bases) that
connect to its
complementary codon on
the mRNA
• has a specific amino acid on
the other end that goes with
the specific anticodon
rRNA (ribosomal RNA)
• links amino acids
together in the ribosome
to make a protein
Overview of Protein Synthesis:
DNA
Transcription
mRNA
Translation
Protein
(Traits)
Definition of Protein Synthesis
• Making a protein by first transcribing (making
a readable copy of) a gene and then translating
its genetic code into an amino acid chain
Transcription = creating an RNA copy
happens in the nucleus
1. DNA unzips to
expose one gene
(code for one
protein)
2. RNA bonds in a
complementary way
AU
CG
TA
GC
Now you practice!
TAC
CAC
CTC GGC
ATT
DNA
mRNA
GTA
AAT GGG TCA
TTG
DNA
mRNA
Translation = mRNA is decoded into an
amino acid sequence - at the ribosome
(nucleic acid code becomes a protein)
Translation
1. The ribosome hooks onto the mRNA and starts
translating at a start codon (AUG)
2. A tRNA, carrying an amino acid, is
pulled in by the ribosome & its
anticodon binds to the mRNA codon.
3. The next tRNA anticodon is also bound, & the
ribosome joins the two aa’s, then cuts off the 1st
tRNA & releases it (tRNA’s are recycled)
Translation
4. The ribosome continues, moving down the
mRNA, binding new tRNA’s and adding to
the polypeptide until it
reaches the stop codon.
5. The stop codon signals the
end of the protein, so the ribosome lets go. A
new protein has been made that will now
determine the traits of your body.
So how do YOU do it?
The Genetic Code
mRNA
Each
codon codes for one
amino acid
------------------------->
To determine which
amino acid is added to
the polypeptide, work
outwards (largest
letter to smallest) in
the wheel w/ codon
letters (mRNA)
You might also see one like
this…
Practice!
AUG
GUG
GAG
CCG
UAA
Questions to add to your
notes on Protein Syn.
• What are 3 major differences between DNA
and RNA?
• Explain how proteins are connected to traits.
• Describe the functions of the 3 types of RNA.
• What are the 2 parts of protein synthesis and
where does each take place?
• What is the purpose of transcription?
• What is the purpose of translation?
• Another animation
• The BIG PICTURE
• An interactive animation that will help you
understand this can be found at:
http://www.wiley.com/college/boyer/0470003
790/animations/translation/translation.htm
In your summary sentence:
A frameshift mutation causes….
which changes the _______________________,
which makes a different _____________, and
therefore changes the ______________ of the
animal.
EQs:
• List 2 similarities and 2 differences
between DNA & RNA.
• What is the process by which your genes
are turned into traits? Describe in detail!