PROTEIN SYNTHESIS
NAME:______________________________________________________________________ PERIOD:____
Objective: Demonstrate your knowledge of protein synthesis by decoding a sequence of DNA into a protein
using mRNA, rRNA, and tRNA.
Starter: Using the picture provided fill in 3’ or 5’ in the spaces with ____?. For DNA polymerase assign an
arrow in the direction it is adding nucleotides (hint, there is some information in the key that will help you
answer this question. Remember polymerase moves in the direction that it is ADDING nucleotides to, NOT
the direction of the template (original) strand.
Second part of the starter
Identify what these enzymes do in DNA replication
Helicase:
DNA Polymerase:
Primase:
Ligase:
Part I RNA and how it’s different from DNA
DNA has 4 different nucleotides write them down below and pair them accordingly
RNA is different from DNA in that it has Uracil (U) instead of Thymine (T). Write down the nucleotides for
RNA below and pair them accordingly.
..RNA also has a different sugar than DNA, DNA has the sugar deoxyribose and therefore we call DNA
Deoxyribonucleic acid. RNA uses the sugar ribose, and therefore we call RNA ribonucleic acid.
Make a note of the difference between Deoxyribose and Ribose below.
The final difference between DNA and RNA is that DNA is double stranded and RNA is generally single
stranded.
Final DNA/RNA comparison
Summarize the similarities and
differences between DNA and RNA
below (there are 3 main differences, and
many similarities. Use the pictures
provided to assist you).
Similarities
1.
2.
3.
4.
Differences
1.
2.
3.
PART II Types of RNA
Describe the various types of RNA below and match them with
the appropriate picture.
Messenger RNA (mRNA):
Ribosomal RNA (rRNA):
Transfer RNA (tRNA)
PART III Transcription
The first step in creating a protein from a sequence of DNA is to “transcribe” DNA into messenger RNA
(mRNA). In DNA, A’s pair with T’s and G’s pair with C’s. RNA is different from DNA in that RNA uses
Uracil instead of Thymine. So when mRNA is being transcribed from a sequence of DNA we need to make
sure and write U instead of T.
Here’s an example
Questions
1. Now that we know how RNA base pairings work let’s try transcribing a sequence of DNA into mRNA. Use
the sequence provided to create mRNA
PART IV Codon Wheel
There are ____ different amino acids used to create a protein. These amino acids are determined by a specific
code on the mRNA molecule. Every 3 nucleotide sequences on mRNA is a specific code for an amino acid.
After mRNA is created it is shipped out of the nucleus and sent to the ribosome. The ribosome is where the
conversion of these nucleotide sequences into amino acids takes place.
The term we give these 3 sequenced sections of nucleotides is called a codon. Every codon “codes” for a
specific amino acid, and some amino acids have multiple codons that code for them. Reference the example
below.
Notice how the codon for the amino
acid glutamine can be the sequence
CAG OR CAA.
To be able to decipher an mRNA sequence you will need what’s called a “RNA Codon Wheel.”
Take a look at our example from above
and see if you can decipher how to read
a codon wheel.
In case you had difficulty figuring it out
let’s do one together.
Let’s use the sequence AUG
 Step 1 Match the first letter of the 3
letter codon with the innermost circle of
letters.
 Step 2 Match the second letter of the
3 letter codon with the next ring of
letters.
 Step 3 Match the third letter of the 3
letter codon with the final ring of
letters.
 Step 4 Identify the protein that
corresponds with this sequence.
TAKE NOTE
Notice how many of the amino acids
have multiple codons that code for their
use.
Questions
Identify the amino acids from the following mRNA codon sequences.
UCG
UCU
GCA
AGG
GUG
PART V tRNA (Transfer RNA)
At the beginning of this assignment we learned about 3 different
types of RNA (mRNA, rRNA, & tRNA). mRNA is the “messenger”
that brings the coded sequence to the rRNA (ribosome or
construction factory), but what brings the amino acids to their
corresponding 3 sequence codons? These are the tRNA (transfer
RNA).
If a three-nucleotide sequence on the mRNA is called a codon, then
its corresponding sequence on the tRNA is called the anticodon.
These anticodons on tRNA will only match up with their codons on
mRNA and vice versa so we always get the correct pairing. Every
tRNA with a specific anticodon has a specific amino acid it carries;
however, many amino acids have multiple tRNA that can carry them.
Question
1. What are the ANTICODON(S) (not the codon) for the amino acid Valine (Use the codon wheel on the
previous page to help answer this question)?
PART VI Start & Stop Codons
The ribosome (rRNA), where the protein is being assembled, needs to have a specific codon to tell it when to
begin assembling the protein. It doesn’t just start by adding amino acids to the first three nucleotides in the
mRNA sequence. The ribosome will continue along the mRNA until it reaches the start codon which is
ALWAYS AUG. AUG ALWAYS and ONLY codes for methionine so every protein ever assembled begins
with methionine (probably a great quiz or test question hint hint).
The ribosome also needs to know when to stop assembling the protein, and there are multiple stop codons that
can tell it to do this.
Question
1. Using the amino acid codon wheel write down the codes for the three types of stop codons.
PART VII Transcription & Translation Summary
This process where we create a protein from a sequence of DNA is called transcription & translation (or protein
synthesis). Using your own words describe transcription and translation in a short sentence.
Transcription:
Translation:
PART VIII Transcribe & Translate A Word
Phrase Activity
Using what we’ve learned we are now going to use
the magnificent “Porter’s alphabet codon wheel” to
transcribe and translate a word phrase. Before we
begin, observe the alphabet codon wheel and
answer the following questions.
Questions
1. What do the letters of the alphabet in the
outermost ring represent?
2. What does the phrase you are about to decode
represent?
Using the sequence of DNA provided by your teacher TRANSCRIBE then TRANSLATE the DNA sequence
onto the lines below. Remember that you
DO NOT start translating your mRNA sequence until you
arrive at the start codon, and that you stop translation at the stop codon. Please note that I have created 20
different phrases for you all to transcribe and translate, so at most there will be 2 of the same phrases. I will be
checking these phrases for accuracy as this is a very important assignment.
You need to record your DNA sequence letter here.
DNA Sequence letter_____
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__ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
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__ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
__ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
__ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
__ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __
DNA SEQUENCE A
These are DNA sequences you will need to
TRANSCRIBE then TRANSLATE
TAGCATAATACAAATTCTGGACCTTTGATTGTACCTTGGGGTCC
TTGATATTGACGTTAGGGAATACCTTAGGCAGTTTACGCTTAAGT
TGGTTGAGGTCCTAATTACGGCCTACCAGGTTAATATTACGAAGG
TGCGCGGCTTCCGTATTCCGGTGTGGACGGTTATTTAGAATTCTCT
TCCCTCCGCGGACCCCTTCTGGTGCACCCGGCATTCTCCAGAATT
DNA SEQUENCE B
These are DNA sequences you will need to
TRANSCRIBE then TRANSLATE
TAGCATAATACCGGGATTTGGGGGCGGACGATTTAGTACGGTTA
TTCGGGACCTTGGGTAGCTCCCGAGATTTTGGCGCAAGGTTGCGG
TTATTCGGTACCTTAGCGTCCATGAAAACCGAATTGCGTTTCGAT
TTACGGTGCACCCGGCCCTTAGGTAATACCCGATTCTCCAGTTTC
ATCTCCCTCCGCGGACCCCTTCTGGTGCACCCGGCATTCTCCAGA
DNA SEQUENCE C
These are DNA sequences you will need to
TRANSCRIBE then TRANSLATE
TAGCATAATACCATTTATTCAGATTCAACAAAACCTTAGCTTCC
CGACCGTGCTCCATATTCGCCCGATCCTTAGGACGATGTGATTGT
GCACGATTAGGGAATACCGCATGGCATCTCTGCGACCGAACCTTA
TCCCCGTTGCGTTGTACCTGTCGTTGCGATACCCGATTGCTATGT
GGTATCGCACCCGGCATTCTTCTCCCTCCGCGGACCTTCTCATGCC
DNA SEQUENCE D
These are DNA sequences you will need to
TRANSCRIBE then TRANSLATE
TAGCATAATACCCCTTTGATAGCAGGTAATCCGATCTATCCGAT
CTATCCTTGGGAAGTACCGTATGTGATGCATGCCGTTGTGATTTG
GGTGACTGTACCTATTTAAGAAGGTCCAGATGCTTGAGCTCCCGG
TTCGCATGAGACGACTGCGCGGCAACCTTAGGTTCCTTTGGCAAA
CGACCTTTAGGGAATACTTCTCCCTCCGCGGACCTTCTCGACCGCA
DNA SEQUENCE E
These are DNA sequences you will need to
TRANSCRIBE then TRANSLATE
TAGCATAATACAGTGGCTTGTCCTTAGCGACCTTTGGCACCTTT
ATATTGACGTTAGGGAATACCATATTCAGATGCGACTGGAGGTGC
TCCCGACCTTTGCAGACCTTTAGAAGATTCTATCGCACCGAATTC
GATTCCCGACCCTGCTCCTTAGGCCCTTGCGATTTACGATTGGGC
GACTGCACCTTCGAATCCCGGGATTTTTTACGAGCAATCCCTTCTC
DNA SEQUENCE F
These are DNA sequences you will need to
TRANSCRIBE then TRANSLATE
TAGCATAATACCTGGGTTTCTAGTTAGGGAATACCCCGTTCTAG
TCCGCTGACTTATGTGGAGACTGTACCTAGTTCGATCTAGCGTCC
TTGAGGAGGTTCTAAGCGACCAAATTCTGGACCCGATTCACCTGA
GGTAGCTGCGATGCTCGGTTGGGGAGTACCCGACCGTGCACCTAG
TTCGATAGGAGCACCTTTGATTTCTGGGGTAGTACCAAATTCTGG
ATCGAATCCCGGGATTTTTTACGAGCAATCCCTACGAGAGCAATC
DNA SEQUENCE G
These are DNA sequences you will need to
TRANSCRIBE then TRANSLATE
TAGCATAATACCCTTTGGATAGCACCTAATTCGATCTGTCCTTT
GGAAGTACCGGATTCTCCGTAAGATTTAAATCCATGTTTCTATGC
GCGACCCTTTTTGACCTGACCTTTTCCAGTTGAAGGAGAACCCAT
TTCAAAATTCGGGATTTTTTACGAGCAATCCCTTACGAGCAATCG
CGATGCTCGGTTGGGGAGTACCCGACCGTGCACAATCCCTGAGAG
DNA SEQUENCE H
These are DNA sequences you will need to
TRANSCRIBE then TRANSLATE
TAGCATAATACCATTGCAGATTATGCCGCTTAGGTAAGTCCTTA
GGGACCAAATTCTGAGATGCCTGCAGAGAGACCTATTTAAGAAGG
ACCCCTTGTAGAGTATCCAAATTCTGAACCGCCTGGGACGACTGC
TGTAGTTCCTTAGGTACCTTTGGGAAAACCAGTTTAGAAGAGTTA
GACTGAAGACGGTCCGCATTACGATGATTGCGATTATTCGGTATT
TACCCGACCGTGCACAATCCCTGAGACAATCCAATCCCTGAGACA
DNA SEQUENCE I
These are DNA sequences you will need to
TRANSCRIBE then TRANSLATE
TAGCATAATACTATCCGAAATCCATATTTCTGTGCACCTTGGGC
TCCTGTGGGTGCATAAAATCCTTCGAGACCGCCTTCATGTGTTTC
GGTTGCTCCTGCAGAGCTTGCTCCTATCCTTGTGGAACCAAATTC
TGAACCGACTTCTGGAGGAGCTCCATATTGCTGTGCACCTTTTCC
GAGGATTTATGTGGCAGTACTCCTGAGACAATCCAATCCACATCC
PHRASES KEY
SEQ.
LETTER
A
B
C
D
E
F
G
H
I
PHRASE
YOU ARE AN AMAZING INDIVIDUAL WITH LIMITLESS POTENTIAL
TRANSCRIPTION AND TRANSLATION IS MY FAVORITE THING TO DO
BIOLOGY IS MY FAVORITE SUBJECT I HAVE EVER TAKEN
HARD WORK AND PERSEVERANCE WILL LEAD TO SUCCESS IN ANYTHING
DNA IS AN AMAZING MOLECULE THAT ALLOWS FOR THE INHERITANCE OF TRAITS
KNOWING HOW SCIENCE WORKS ALLOWS YOU TO UNDERSTAND THE WORLD AROUND YOU
HARD WORK AND NO PLAY MAKES JACK A DULL BOY
BELIEVING IN YOURSELF WILL HELP YOU SUCCEED IN ANY DIFFICULT SITUATION
WHY MAKE AN ENEMY OF SOMEONE ELSE WHEN YOU COULD MAKE A FRIEND
PROTEIN SYNTHESIS EXIT QUIZ
1. Which of the following is NOT one of the uses of RNA in a eukaryotic cell?
A. A ribosome where proteins are created.
C. Bringing amino acids to a growing protein chain.
E. All the above are uses of RNA in a eukaryotic cell
B. Passing on genetic information to offspring.
D. A message from DNA to the ribosome.
2. All of the following are differences between DNA and RNA in a eukaryotic cell EXCEPT?
A. DNA has one fewer oxygen in its sugar than RNA
B. DNA is double stranded and RNA is generally single stranded
C. DNA uses Thymine (T), and RNA uses Uracil (U)
D. DNA is found outside the nucleus and RNA is found inside the nucleus
E. All the above are differences between DNA & RNA
3. The definition of transcription & translation is?
A. Transcription is where DNA is duplicated into 2 copies, & translation is where that copy is made into RNA.
B. Transcription is where RNA is created from DNA, & translation is where that RNA is made into a protein.
C. Transcription is where RNA is created from a protein, & translation is where DNA is made from RNA.
D. Transcription is where DNA is created from RNA, & translation is where the DNA is made into a protein.
E. Transcription is where RNA is duplicated into 2 copies, & translation is where that copy is made into DNA.
4. All of the following are the same mRNA sequences, which of the following shows an accurate example of when
you would start adding amino acids to a new protein?
The first 3 nucleotides in the sequence
Starting from the first nucleotide we divide
the mRNA into codons of 3 nucleotides
and start at the first AUG we find
Starting from the first AUG we find and
then divide the mRNA into 3 nucleotide
codons
Starting from the first AAA we find and
then divide the mRNA into 3 nucleotide
codons
QUESTION 5 IS ON THE BACK OF THIS PAGE!
5. Using the amazing alphabet codon wheel decipher the following DNA sequence.
GGACATACGCTTTGAGGCGAAAAATCGCTTA
A. SALTY
B. SALLY
C. SALTS
D. SILLY
E. SAPPY
ANSWER KEY
1. B
2. D
3. B
4. C
5. A