LAB EXPERIMENT: DNA and Protein Synthesis

Learning Objectives

Upon completion of this laboratory, you will be able to:

? Review the structure and function of DNA.
? Identify the codons that code for amino acids in DNA and RNA.
? Explain the purpose of start and stop codons in protein synthesis.
? Summarize the steps involved in protein synthesis and define a ribosome and its three sites.
? Summarize the steps of transcription, including: initiation, elongation, and termination.
? Summarize the steps of translation, including; initiation, elongation, and termination.
? Illustrate and model the processes of transcription and translation.
? Construct a series of tRNA molecules and write the anti-codons and amino acids each tRNA carries.
? Explain the difference in the number of amino acids that were present at the start and at the end of the translation model.

Exercise 1: Protein Synthesis

In this exercise, you will model the steps of protein synthesis, starting with a single strand of nucleotides and ending with a protein.

1. Print 6 copies of the DNA Nucleotide Template, 4 copies of the RNA Nucleotide Template, and 1 copy of the tRNA Template. It is preferable, but not necessary, to print them in color. The templates are located in the "Supplemental Documents" folder of your digital courseware.

2. Review the coding strand of DNA (5' to 3') in Data Table 1 of your Lab Report Assistant.

3. Create the template strand of DNA (3' to 5') and record in Data Table 1.

4. Gather the scissors, tape, and the 6 printed copies of the DNA Nucleotide Template. Cut out the nucleotides from the template. It is not necessary to cut out the entire nucleotide; rather, cut the nucleotide in a rectangular shape, only cutting out the details of the nitrogenous bases. See Figure 5.

5. Using the DNA nucleotides, create the entire double strand of DNA by matching up and taping together the base pairs. See Figure 6 as an example.

6. Take a photograph of the completed double strand of DNA with your name and the data showing in the photograph. Resize and insert the photograph into Data Table 2 of your Lab Report Assistant. Refer to the appendix entitled "Resizing an Image" for guidance with resizing an image.

7. Determine the mRNA strand that transcription would produce from the DNA template strand and record the mRNA strand in Data Table 1.

8. Gather the 4 printed copies of the RNA Nucleotide Template. Cut out the nucleotides from the template. It is not necessary to cut out the entire nucleotide; rather, cut the nucleotide in a rectangular shape, only cutting out the details of the nitrogenous bases.

9. Using the RNA nucleotides, create the mRNA strand by matching up and taping together the base pairs.

10. TakeaphotographofthemRNAstrandwithyournameandthedateshowinginthephotograph. Resize and insert the photograph in Data Table 2.

11. Starting with the first mRNA nucleotide, determine what amino acids the codons in the mRNA are coding for and record in Data Table 1.

12. Gather the printed copy of the tRNA Template and cut out the tRNAs.

13. Build the line of tRNAs that would flow into the A site during translation. Write the anti- codons into each tRNA and the amino acid the mRNA codes for. See Figure 7 as an example of the tRNA that would be created from the mRNA codons CCU.

14. Take a photograph of the tRNAs (in order) with your name and the date showing in the photograph. Resize and insert the photograph in Data Table 2.

15. Write the name of the each amino acid in the final protein created from translation and record in Data Table 1.

16. When you are finished uploading photos and data into your Lab Report Assistant, save your file correctly and zip the file so you can send it to your instructor as a smaller file. Refer to the appendix entitled "Saving Correctly" and the appendix entitled "Zipping Files" for guidance with saving the Lab Report Assistant correctly and zipping the file.

Questions

A. How many amino acids were coded for by the mRNA? How many amino acids were present in the final protein chain created in translation? In detail, explain the differences in the two numbers; why were some amino acids coded for by the mRNA but not present in the final protein chain? What amino acids were omitted from the final protein chain? Explain your answers.

Attachment:- Attachments.rar