Name: ______Group #: _____

PROTEIN SYNTHESIS ACTIVITY

Materials (per group):

1 group plastic bag with:

  • 18 DNA bases (yellow)
  • 19 codons (18 pink + 1 white- on mRNA)
  • 18 tRNA anticodons (blue- on tRNA)

6 balloons (6 amino acids)

1 piece of yarn (peptide bonds that hold the amino acids together)

Procedures:

PART 1

1)Create a DNA strand out of 18 yellow cards, starting with the letter sequence T A C. This will represent one side of a DNA strand.

2)Record your DNA sequence that you created: ______

3)Next, match the mRNA codons (pink) with the corresponding DNA strand that you created.

4)Record your mRNA sequence: ______

5)Leave your mRNA strand in place and remove your DNA sequence cards. You can return them to your bag.

6)Next, create your tRNA sequence codes by matching the corresponding blue letters with your mRNA strand.

7)Record your tRNA sequence: ______

8)Now, referring to p. 192 in the textbook, figure out which amino acids each tRNA brings to the ribosome. REMEMBER: You must look up the complementary mRNA sequence in the Genetic code chart!

9)Label your balloons with the name or abbreviation of the amino acids in the correct order.

10)Once you have the proper order of amino acids, blow up your balloons and attach them all together using yarn.

11)By linking all the balloons together, you have now created a POLYPEPTIDE CHAIN, a.k.a PROTEIN!

12)Record your amino acid sequence. (Hint: Watch for STOP codons!)______

PART 2

1)Go back to your mRNA strand sequence (pink).

2)Create a POINT MUTATION by replacing the 4th base (counting from left to right) with the white mRNA base card.

3)With this new mutation, re-record your sequences of each below:

  1. mRNA strand ______

b. complementary tRNA strand ______

c. amino acid sequence ______

4)Again, go back to your mRNA sequence above (with the white base).

5)Add back in your pink base you replace in #2 above. Place this base after the 5th base in the mRNA sequence (counting left to right). KEEP YOUR WHITE BASE CARD IN PLACE! This is called a FRAMESHIFT MUTATION.

6)Repeat step # 3 above following through the entire process again. Re-record your sequences of each below:

  1. mRNA strand ______

b. complementary tRNA strand ______

c. amino acid sequence ______

7)Clean up your supplies- Rubberband all cards and put back in Ziploc bag. Return all supplies and your created polypeptide chain to Ms. Rago.

8)Begin working on the analysis questions below.

ANALYSIS QUESTIONS:

1)How did the point mutation affect your protein?

2)How did the frameshift mutation affect your protein?

3)Which of the above mutations is more harmful for an organism? Explain your answer.

4)What part of this activity was TRANSCRIPTION? What part was TRANSLATION?

5)Why do you think that some codon sequences represent the same amino acid? Explain your reasoning. (Example:GGC=glycine as well as GGA,GGG,GGU= glycine)