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3.3: Protein Synthesis Pizza

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  • Page ID
    138516
    • Katherine E. Brent & Sydney Quinn Chizmeshya

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    Protein Synthesis Pizza

    Format: In-person or online


    A ribosome involved in translation - the last major step of protein synthesis.

    Author: Jess Whalen

    Source: Modified from Taco Protein Synthesis Activity, Susquehanna Township School District.

    Time needed: 30-45 minutes

    Learning Objectives

    • Explain the roles of DNA, mRNA codons, ribosomes, and amino acids in protein synthesis
    • Summarize protein synthesis: key steps and locations in a cell
    • Practice transcription and translation

    Supplies Needed

    • Protein Synthesis Pizza Worksheet (included)
    • Pizza Ingredients List (included)
    • Optional Worksheets: Build Your Own Protein Pizza and Extra Practice: Go From RNA to DNA (included)
    • DNA Sequences (included) printed and cut into strips

    Readings

    Introduction

    In this activity, students work through the steps of transcription (DNA to RNA) and translation (RNA to amino acid chain) in protein synthesis. Instead of creating proteins, the final product is a pizza recipe with specific toppings. Just as a pizza is made up of many specific ingredients, so too is a protein made up of specific amino acids.

    Steps

    • Students should be divided into small groups of two or three.
    • Each student begins with a copy of the Protein Synthesis Pizza Worksheet, the Amino Acids Reference Sheet or Explorations Figure 3.25 , and the Pizza Ingredients List. If you want to expand the activity you can also provide students copies of the Build Your Own Protein Pizza Worksheet.
    • Instructors should pass out one DNA sequence to each group (provided on a paper strip).
    • Students will work through the questions and record their answers on the Protein Synthesis Pizza Worksheet.

    Review Questions

    1. In what ways are proteins similar to pizza? How is relating proteins to pizza useful?
    2. In our pizza metaphor, what are the amino acids?
    3. What happened when your pizza had a few ingredients that were unexpected? What is the equivalent scenario when it comes to proteins? That is, which ingredients make up a protein, and what happens if a few ingredients are changed?
    4. How do the exercises in this activity relate to natural selection?

    Adapting for Online Learning

    1 Not adaptable 2 Possible to adapt 3 Easy to adapt

    Instructors could provide students their own pizza recipe and the worksheet to do this activity individually, or instructors could distribute an electronic version of the worksheet and recipe (e.g. in Google Docs) and ask students to complete the activity in small groups online.

    Tips and Suggestions

    It can help to explain to students that their Amino Acids Reference sheet will show them how to transcribe the nucleotide bases from DNA to mRNA, and they may rely on this sheet to find the complementary nucleotide bases. Students usually use the chart for a few questions before they realize that they can actually transcribe the nucleotide bases faster by themselves. That means they are learning how to transcribe the bases from DNA to RNA!

    A table like the one below may be helpful for students as they learn to transcribe DNA triplets into mRNA codons. The row in the middle is a ‘help’ row where students can insert a ‘T’ wherever there is an A in the DNA, or (if working backwards) where there is a ‘U’ in the RNA codon. The other nucleotides follow DNA rules of complementarity (A-T and C-G). This table structure matches the optional worksheet Extra Practice: Go from RNA to DNA (included)

    DNA AAA TAC GAC GAA AAT ATT GTT ACA ATT
    help TTT _T_ _T_ _TT TT_ T_ _ _ _ _ T_ T T _ _
    RNA UUU AUG CUG CUU UUA UAA CAA UGU UAA

    For Further Exploration

    Leddin, Emmtt. Amino Acids and DNA and RNA Bases. https://emleddin.github.io/comp-chem-website/AMBERguide-AAs-DNA-RNA.html. CC BY-SA 4.0

    Serendip Studios. Introduction to the Functions of Proteins and DNA. https://serendipstudio.org/exchange/bioactivities/proteins. CC BY-NC 4.0

    Serendip Studios. How Genes Can Cause Disease - Introduction to Transcription and Translation. https://serendipstudio.org/exchange/waldron/gene. CC BY-NC 4.0

    References

    Mann, Hayley, Xazmin Lowman, and Malaina Gaddis. 2019. “Chapter 3: Molecular Biology and Genetics.” In Explorations: An Open Invitation to Biological Anthropology, edited by Beth Shook, Katie Nelson, Kelsie Aguilera, and Lara Braff. Arlington, VA: American Anthropological Association. http://explorations.americananthro.org/

    Image Attributions

    Ribosome mRNA Translation by LadyofHats has been designated to the Public Domain.

    Protein Synthesis Pizza Worksheet

    Background

    Proteins are complex chemicals made up of different amino acids, of which there are a total of 20 types. Different combinations of amino acids produce different proteins. The process of making a protein is called protein synthesis, and involves two major steps: (1) transcription and (2) translation.

    In transcription, a DNA strand in the nucleus forms the template for the creation of single-stranded messenger RNA (mRNA). Transcription occurs when an enzyme called polymerase strings together free-floating RNA nucleotide bases that are complementary to the exposed strand of DNA.

    For translation, the mRNA strand leaves the nucleus for the cytoplasm. There, a ribosome translates the mRNA strand. Ribosomes read three nucleotides of the mRNA at a time (called a codon) and, with the help of single-stranded transfer RNA (tRNA), matches the codon to the corresponding amino acid. This amino acid is added to the growing protein chain. When a ‘stop’ codon is read, the protein is complete. As the amino acid chain exits the ribosome, it folds into its unique shape, and can go to work in the body.

    Part 1: From DNA to Amino Acids

    This activity breaks down protein synthesis using the metaphor of PIZZA!

    *Warning: this activity may make you hungry!*

    Use your Amino Acids Reference Sheet to complete the following table. Fill in the blank spaces of each row with either the missing DNA triplet, the mRNA codon, or the Amino Acid. While there are actually multiple codons that code for any one amino acid, for this activity there only needs to be one DNA triplet and one corresponding mRNA codon recorded for each amino acid.

    Remember: RNA uses uracil (U) instead of thymine (T)!

    DNA mRNA codon Amino Acid
    TTG AAC Asparagine
    GGG   Proline
      UAU Tyrosine
      CAC Histidine
    CGT GCA  
    AAA    
    TTT AAA  
    CAA    

    As you fill in the chart, you will learn how to transcribe the nucleotide bases of DNA (the As, Ts, Gs, and Cs) into mRNA using the “language” of RNA (which replaces any ‘T’ with a ‘U’). As you continue to fill in the chart you may find that you can transcribe the triplets by yourself, using your knowledge of base pairings, without using the amino acids chart at all!

    Part 2: Decoding a Protein Pizza

    Your instructor will give you a DNA “pizza recipe” in DNA base triplets. Use your knowledge of transcription and translation to figure out what kind of pizza you have!

    1. Write down the DNA pizza recipe in the DNA section of the chart, three letters at a time, going vertically down the chart in the far left column.
    2. Transcribe each DNA triplet in the pizza recipe into a mRNA codon.
    3. Once each triplet has been transcribed into mRNA, you can begin to translate the mRNA code to construct your pizza. Use the Pizza Ingredients List to decode what ingredients are in your pizza. The ingredients in the chart are in mRNA, so refer to your mRNA codons in the second column.
    4. Use your Amino Acids Reference Sheet to figure out which amino acid corresponds to each mRNA codon. In this case you are doing the work of the ribosome: matching the mRNA codon to the specific amino acid that is needed for the growing protein chain. Just like all of the ingredients together make a tasty pizza, so too does each amino acid play an important role in making up a larger protein!

    DNA
    Pizza Recipe Code

    Write the recipe in this column, 3 nucleotides at a time.

    mRNA

    Codon

    Transcribe the DNA code into the corresponding mRNA codon

    Pizza ingredient

    Record the corresponding pizza ingredient, according to the ingredients chart (Use the mRNA codon to look it up.)

    Amino Acid

    Record the corresponding amino acid (for a protein) using your amino acid chart!

    Example:

    AAA

    Example:

    UUU

    Example:

    Stuffed crust

    Example:
    Phenylalanine
           
           
           
           
           
           
           
           
           

    Part 3: Reflection

    Did your pizza have any ingredients that you would not usually find on a pizza? Just like one ingredient can make a pizza unique, so too can one new or different amino acid create a protein that is different from the protein that was supposed to be synthesized. DNA mutations that change, move, or delete a letter in the original DNA triplet can, through protein synthesis, result in the creation of different and new proteins in the body.

    A protein that differs from the original protein that was supposed to be produced can sometimes be a good thing for an organism. If the protein results in a new functioning that gives the

    organism an advantage in its environment then the “incorrect” protein would be beneficial, helping the organism achieve reproductive success. That protein could be selected for through the process of natural selection. In that case, the “incorrect” protein would increase in frequency in the population, and become the more common protein over time (and no longer be considered “incorrect”).

    Amino Acids Reference Sheet

    The 20 Amino Acids in Human Proteins and How They Are Coded For

    Cells in the human body use information in the genetic code to directly encode 20 amino acids. The table below displays how this is done. First, a DNA base triplet is copied to create mRNA in the language of RNA. The mRNA then travels to the cytoplasm, where the ribosome reads each mRNA codon to assemble the corresponding amino acids into a growing protein chain. The “stop” codon is the last triplet in the process. It tells the ribosome that the process of making that specific protein is complete.

    This table lists DNA base triplets and their corresponding mRNA codons that the ribosome reads to attach each specific amino acid. Some amino acids can be made more than one way.

    Amino acids that can be made one way:

    Amino Acid DNA base triplet mRNA codon
    Methionine TAC AUG
    Tryptophan ACC UGG

    Amino acids that can be made two ways:

    Amino Acid DNA base triplet mRNA codon
    Asparagine TTA or TTG AAU; AAC
    Aspartate CTA or CTG GAU; GAC
    Cysteine ACA or ACG UGU; UGC
    Glutamate CTT or CTC GAA; GAG
    Glutamine GTT or GTC CAA; CAG
    Histidine GTA or GTG CAU; CAC
    Lysine TTT or TTC AAA; AAG
    Phenylalanine AAA or AAG UUU; UUC
    Tyrosine ATA or ATG UAU; UAC

    Amino acids that can be made three ways:

    Amino Acid DNA base triplet mRNA codon
    STOP codon AAT or ATC or ACT UAA; UAG; UGA
    Isoleucine TAA or TAG or TAT AUU; AUC; AUA

    Amino acids that can be made four ways:

    Amino Acid DNA base triplet mRNA codon
    Alanine CGA or CGG or CGT or CGC GCU; GCC; GCA; GCG
    Glycine CCA or CCG or CCT or CCC GGU; GGC; GGA; GGG
    Proline GGA or GGG or GGT or GGC CCU; CCC; CCA; CCG
    Threonine TGA or TGG or TGT or TGC ACU; ACC; ACA; ACG
    Valine CAA or CAG or CAT or CAC GUU; GUC; GUA; GUG

    Amino acids that can be made six ways:

    Amino Acid DNA base triplet mRNA codon
    Arginine GCA or GCG or GCT or GCC or TCT or TCC CGU; CGC; CGA; CGG; AGA; AGG
    Leucine AAT or AAC or GAA or GAG or GAT or GAC UUA; UUG; CUU; CUC; CUA; CUG
    Serine AGA or AGG or AGT or AGC or TCA or TCG UCU; UCC; UCA; UCG; AGU; AGC

    Pizza Ingredients


    Important: All ingredients are based on the mRNA code!

    Basics:
    GCA - Thick crust
    GUA - Thin crust

    UUU - Stuffed crust

    Acidics:

    CUA - Marinara sauce

    CUG - Barbecue sauce

    CUU - White sauce
    UUA - Garlic sauce

    Aromatics:

    AAA - Pepperoni

    AAG - Sausage

    ACC - Chicken

    AUA - Bacon

    AUG - Pineapple

    Hydroxylics:

    AGA - Mozzarella cheese

    UGU - Extra cheese (mozzarella)

    Aliphatics:

    AAU - Red onion

    CAA - Black olives

    CCA - Animal crackers

    CGA - Spinach
    GAU - Mushrooms

    GGA - Lettuce

    GUU - Artichoke hearts

    Stop codons:
    UAA - Stop codon
    UAG - Stop codon

    UGA - Stop codon

    *Remember: All ingredients are based on the mRNA code!

    Build Your Own Protein Pizza

    Choose from the ingredients list to make your own pizza! Remember: because the ingredients are in mRNA, you have to fill in the chart working right to left from the Pizza Ingredient. Amino acids can be looked up at the end.

    DNA
    Pizza Recipe Codons

    (write the recipe in this column, 3 letters at a time)

    mRNA

    Codon

    (Once the DNA triplet is transcribed into mRNA, you can find the pizza ingredient)

    Pizza Ingredient

    What pizza ingredient is this, according to the ingredients chart? (Remember: the ingredients in the chart are in mRNA!)

    Amino Acid

    Once you have completed the activity, look up what amino acid this ingredient corresponds to in real life!

    Example:

    TCT

    Example:

    AGA

    Example:
    Mozzarella cheese

    Example:

    Arginine
           
           
           
           
           
           
           
           
           

    Extra Practice: Go From RNA to DNA

    Work backwards from the RNA strand to find the original DNA base triplet! Remember: RNA uses U (not T). So every time you see ‘U’ in the RNA strand, treat it just like ‘T’ to find the complementary nucleotide base!

    DNA _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
    RNA UUU AUG CUG CUU UUA GAU CAA UGU UAA
    DNA _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
    RNA AAA GUA AUG CUA UUA GUU CGA AAU UAG
    DNA _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
    RNA GCA AAG UUA GUU UGU CGA CCA AGA UGA
    DNA _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
    RNA GCA AUG CGA AGA GAU CUU UUA CUA UAA
    DNA _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
    RNA ACC CCA AAU GUA GGA CUU UUA GUU UAG
    DNA _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
    RNA AUA AGA UGU ACC AAU GAU CUU UUU UGA

    DNA Sequences to Provide Students

    DNA AAA TAC GAC GAA AAT CTA GTT ACA ATT
    DNA TTT CAT TAC GAT AAT CAA GCT TTA ATC
    DNA CGT TTC AAT CAA ACA GCT GGT TCT ACT
    DNA CGT TAC GCT TCT CTA GAA AAT GAT ATT
    DNA TGG GGT TTA CAT CCT GAA AAT CAA ATC
    DNA TAT TCT ACA TGG TTA CTA GAA AAA ACT
    DNA TTT AAA TTA GTT ACA TCT CAA GAT ATT
    DNA TAC CAT TCT ACA AAT CAA GCT CTA ATC
    DNA CGT GAC TTC AAT CTA CCT TTA TCT ACT

    Answer Key (RNA & Protein)

    UUU AUG CUG CUU UUA GAU CAA UGU UAA

    Stuffed crust, pineapple, barbecue sauce, white sauce, garlic sauce, mushrooms, black olives, extra cheese, stop

    AAA GUA AUG CUA UUA GUU CGA AAU UAG

    Pepperoni, thin crust, pineapple, marinara sauce, garlic sauce, artichoke hearts, spinach, red onion, stop

    GCA AAG UUA GUU UGU CGA CCA AGA UGA

    Thick crust, sausage, garlic sauce, artichoke hearts, extra cheese, spinach, animal crackers, mozzarella cheese, stop

    GCA AUG CGA AGA GAU CUU UUA CUA UAA

    Thick crust, pineapple, spinach, mozzarella cheese, mushrooms, white sauce, garlic sauce, marinara sauce, stop

    ACC CCA AAU GUA GGA CUU UUA GUU UAG

    Thin crust, animal crackers, red onion, mushrooms, lettuce, white sauce, garlic sauce, artichoke hearts, stop

    AUA AGA UGU ACC AAU GAU CUU UUU UGA

    Bacon, mozzarella cheese, extra cheese, chicken, red onion, mushrooms, white sauce, stuffed crust, stop

    AAA UUU AAU CAA UGU AGA GUU CUA UAA

    Pepperoni, stuffed crust, red onion, black olives, extra cheese, mozzarella cheese, artichoke hearts, marinara sauce, stop

    AUG GUA AGA UGU UUA GUU CGA GAU UAG

    Pineapple, thin crust, mozzarella cheese, extra cheese, garlic sauce, artichoke hearts, spinach, mushrooms, stop

    GCA CUG AAG UUA GAU GGA AAU AGA UGA

    Thick crust, barbecue sauce, sausage, garlic sauce, mushrooms, lettuce, red onion, mozzarella cheese, stop

    This page titled 3.3: Protein Synthesis Pizza is shared under a CC BY-NC 4.0 license and was authored, remixed, and/or curated by Katherine E. Brent & Sydney Quinn Chizmeshya via source content that was edited to the style and standards of the LibreTexts platform.