Protein Synthesis
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Transcript Protein Synthesis
11/27/2012
Take a lime green slip, a notes sheet,
and a picture sheet from the front table.
Glue/tape/staple them into your
journals according to the following
instructions:
The lime green slip must be first before
the notes and the picture.
The notes and the picture should be
placed on pages that face each other.
Protein Synthesis
DNA vs.RNA
• Double-stranded
• Deoxyribose
• A,G, C, T
• Single stranded
• Ribose
• A, G, C, U
DNA vs.RNA
Nucleus
The office
The Boss never leaves
DNA – The Boss
mRNA – Ms. Rene
Secretary
She’s a
foreigner
Protein Synthesis
Protein synthesis is the making of proteins,
using the information that is found in DNA.
Proteins are long chains of small molecules
called amino acids. Different proteins are
made by using a different sequence of amino
acids.
Pieces of information in DNA are
called
genes.
Transcription: means write across
Protein synthesis begins with the DNA
molecule. The DNA of this gene will
unzip like it does in replication. *The
enzyme that separates the DNA strand
at a specific gene is helicase.
In protein synthesis, only one strand of
the DNA will be used.
Transcription: means write across
A single strand of mRNA forms and
transcribes (copies) the genetic
information from the DNA. This strand of
RNA is called messenger RNA or mRNA.
*The enzyme that connects and assembles
the ribonucleotides is called RNA
polymerase
The DNA “zips” closed and remains in the
nucleus .
The mRNA will leave the nucleus and travel
to a ribosome.
RNA which stands for
RIBONUCLEIC ACID is
single stranded,
contains a ribose sugar, and
has Uracil instead of Thymine.
Comparing RNA and DNA
Image courtesy of Wikimedia Commons
5’DNA Helicase3’
5’
A T
G C
T A
A T
C G
G C
G C
A T
T A
C G
T A 5’
3’
Touch the
helicase!
3’
5’
3’
A
A
T
C
G
U
5’
A
G
T
A
C
G
G
A
T
C
T
3’
3’
T
C
A
T
G
C
C
T
A
G
A 5’
5’
Assemble
your
mRNA
strand!!
3’
Hit Me
when
done!
5’
A
A
3’
T
C
G
U
5’
RNA
polymerase
A
G
T
A
C
G
G
A
T
C
T
3’
3’
T
C
A
T
G
C
C
T
A
G
A 5’
3’
5’
A
G
C
C
U
A
C
U
A
G
U
5’
3’
A
A
T
C
G
U
5’
3’
A T
G C
T A
A T
C G
G C
G C
A T
T A
C G
T A 5’
3’
5’
3’
U
C
A
U
G
C
C
U
A
G
A 5’
3’
Protein Synthesis- Part 1
Transcription
From HHMI’s Biointeractive: DNA
Animations/Transcription (basic)
http://www.hhmi.org/biointeractive/dna/D
NAi_transcription_vo1.html
11/28/2012
Take out your notes from
yesterday. On the green slip
of paper, fill in the mRNA row
using the original DNA
strand. Remember: Ms.
Rene cannot write “T”
Quick Review!
Where does
TRNASCRIPTION take
place?
Nucleus
The office
The Boss never leaves
Where do we get the
information to make
different types of
proteins?
DNA – The Boss
Who delivers the
message to the
workers?
mRNA – Ms. Rene
Secretary
She’s a
foreigner
Quick Quiz
1.
2.
3.
4.
5.
What is the name of the enzyme that unwinds
DNA?
What is the process where a secret message
goes ACROSS the nuclear membrane?
What carries the sequence from the DNA out
of the nucleus?
How many strands are copied on the original
DNA molecule?
What happens to the DNA once the
messenger detaches?
rRNA – Bobette
the Ribosome
She builds
proteins one
amino acid at
a time
tRNA – Terry
the Delivery Boy
Terry brings
Bobette
whatever she
needs
Translation
The mRNA contains information in sets of
three and each set of three codes for a
specific amino acid. Each set of three is called
a CODON.
The mRNA molecule will attach to the
ribosome found in the cell. Ribosomes are
also made up of RNA. Ribosomal RNA is
called rRNA.
Where in the cell are ribosomes (rRNA) made?
Translation
A molecule of transfer RNA or tRNA will carry in
the proper amino acid. If the tRNA
ANTICODON matches with the codon
sequence, the tRNA will attach temporarily to the
mRNA strand.
Translation
After a 2nd tRNA molecule matches an mRNA
codon, an amino acid will be deposited. tRNAs
will continue to deposit amino acids when
codons and anti-codons match. The bond
created between 2 amino acids is called a
peptide bond.
The chain of amino acids is called a
polypeptide or a protein
Leucine
5’
Arginine
Valine
U
C
U
A
A
G
U
A
C
Serine
G
G
A
Ribosome
3’
5’
U
C
A
U
G
C
C
U
A
G
A 3’
3’
Leucine
5’
Arginine
Valine
U
C
U
A
A
G
U
A
C
Serine
G
G
A
Ribosome
3’
5’
U
C
A
U
G
C
C
U
A
G
A 3’
3’
Leucine
5’
Valine
A
A
G
U
A
C
Serine
G
G
A
Arginine
Ribosome
3’
5’
U
C
A
U
G
C
C
U
U A
C G
U A 3’
3’
Leucine
5’
Valine
A
A
G
U
A
C
Peptide bond
Arginine
Serine
Ribosome
G
G
A
U
C
U
3’
5’
U
C
A
U
G
C
C
U
A
G
A 3’
3’
Leucine
5’
Valine
A
A
G
U
A
C
Peptide bond
Arginine
Serine
Ribosome
3’
5’
U
C
A
U
G
G C
G C
A U
A
G
A 3’
3’
Leucine
5’
A
A
G
Peptide bond
Arginine
Serine
Valine
Ribosome
3’
5’
U
C
U A
A U
C G
C
C
U
A
G
A 3’
3’
5’
A
S
V
L
G
Arginine
S
AA
V
R
Serine
Valine
Leucine
Ribosome
A U 5’
A U
G C
A
U
G
C
C
U
A
G
A 3’
3’
3’
Quick Quiz
1.
2.
3.
4.
5.
What is the process where the mRNA drops off
the message to the ribosome?
What are the 3 types of RNA?
A sequence of 3 nucleotides on the mRNA
strand that codes for a specific amino acid is
called a what?
What is the name of the bond that is formed
between two amino acids?
How do amino acids get into the body in the
first place?
DNA unwinds and unzips.
Free RNA nucleotides attach to exposed bases.
Bases combine to form mRNA strand. DNA reassembles.
mRNA leaves the nucleus.
The mRNA arrives at the ribosome.
When the codon of the mRNA complements the anti-codon of the
tRNA molecule, the tRNA places the amino acid attached in the
position.
tRNAs continue to deposit amino acids when codons and
anticodons match.
One by one amino acids are added to the growing chain until the
ribosome has reached the STOP codon.
Once the protein has been synthesized completely, it is removed
from the ribosome for further processing and to perform its
function.
Proteins like insulin and lactase exit to the Golgi bodies to be
packaged and shipped out of the cell.
Protein Synthesis- Part 2
Translation
From HHMI’s Biointeractive: DNA
Animations/Translation (basic)
http://www.hhmi.org/biointeractive/dna/DN
Ai_translation_vo1.html
11/29/2012
Please take the 2 worksheets
from the front table, take out
your transcription &
translation worksheet from
yesterday, and your protein
synthesis notes.
Draw the flow
chart in your
journal, then fill
it in using the
following words:
Amino acids,
mRNA,
mRNA codon,
nucleus,
nuclear pore,
peptide bonds,
ribosome,
transcription,
translation
DNA
Transcription
mRNA
AUA
UUG AAG
AGC CAC
AAC
AUA
UUG AAG
UUC
GAG
Translation
Ribosome
UAU
GCU AAA
UCG GUG CGA
UUU
CUC ACU
CAC
AAA
GAG UGA
AGC
GCU
UGA
A-T
C-G
T-A
A-U
C-G
Insert practice here
Last Thought 11/28/11
Write the sequence for a segment of RNA
that codes for the following chain of amino
acids:
valine – serine – proline – glycine – leucine
Explain why your sequence is likely to be
different than your partner’s.