Lab 8 DNA Coding and Protein Synthesis Introduction – Connecting Your Learning

Lab 8
DNA Coding and Protein Synthesis
Introduction: Connecting Your Learning
As covered in a previous lesson, DNA is an abbreviation for the biological molecule called deoxyribonucleic acid. DNA is found in the nucleus of cells and it stores genetic information and
the code for synthesizing proteins. A DNA molecule is organized into sections called genes. Genes code for specific proteins that are vital to living organisms. Proteins are
important because they are the building blocks of cells and, additionally, proteins called enzymes play a key role in catalyzing chemical reactions in living organisms. Proteins
are synthesized in the cytoplasm of cells by ribosomes. Long strands of DNA along with proteins called histones are tightly wound together to form chromosomes.
In order to synthesize a protein, information must be transferred from the DNA in the nucleus of the cell to the ribosomes in the cytoplasm of the cell. The process involves two steps:
transcription and translation. Transcription is the process where the code for a protein found on a specific gene located on DNA is written to another nucleic acid molecule called ribonucleic
acid (RNA). This process takes place in the nucleus of the cell. The molecule of RNA then leaves the nucleus and enters the cytoplasm where the process of translation takes
place. Translation is a process where the code for making a protein (found on a molecule of RNA) is translated into specific amino acids that will comprise apolypeptide (protein).
In this lab, students will simulate the process of protein synthesis by transcribing DNA molecules into RNA molecules and then subsequently, translating RNA molecules into amino acids.
Students will also extract DNA from an onion.

Resources and Assignments
Multimedia Resources

None

Required Assignments

Lesson 10 Lab 8

Required Materials

From the Lab Kit

DNA template cards

Universal genetic code reference card

Ribosome circle

Thermometer

Funnel

100 ml graduated cylinder

2 coffee filters

Measuring spoon (teaspoon)

2 teaspoons salt

Student Provided

Pen or pencil

Standard printer paper (1 sheet)

Scissors

Onion

1 small pot

120 ml water

2 tablespoons liquid dish detergent

Fork (Needed only if a blender or food processor is not available)

Knife

Cutting board or other surface for cutting the onion

Additional water for heating (3-4 cups tap water)

2 small glass, ceramic, or metal mixing bowls

2 cups ice or access to a freezer

2 clear drinking glasses (12-16 oz)

100 ml Isopropyl alcohol (rubbing alcohol), 71% or higher

Blender or food processor

Tape

Optional: (if the student wants to preserve the extracted DNA)

Alcohol (100-200 ml)

Focusing Your Learning

Small clear glass container with a lid

Wooden skewer or toothpick

Lab Objectives
By the end of this lesson, you should be able to:
1. Identify the structure of DNA including the following: nucleotides, base pairing, hydrogen
bonds, and the double helix model.
2. Compare and contrast the structure of DNA and RNA.
3. List and describe the steps of DNA replication.
4. List and describe the steps of transcription and translation, and describe where each
occurs in the cell.
5. Explain the functions of messenger RNA, transfer RNA, and ribosomal RNA.
6. Distinguish between codons and anticodons.
Background Information
DNA and RNA Structure

Assessing Your Learning
Compose answers to the questions below in Microsoft Word and save the file as a backup copy in the event that a technical problem is encountered while attempting to submit the assignment.
Make sure to run a spell check. Copy the answer for the first question from Microsoft Word by simultaneously holding down the Ctrl and A keys to select the text, and then simultaneously
holding down the Ctrl and C keys to copy it. Then, click the link on the Lab Preview Page to open up the online submit form for the laboratory. Paste the answer into the online dialog box by
inserting the cursor in the box for question one and simultaneously holding down the Ctrl and V keys. The answer should now appear in the box. Repeat this process for each question. Review
all work to make sure that all questions have been completely answered and then click on the Submit button at the bottom of the page.

1. How does DNA differ from RNA? (2 points)

2. Where in the cell does each of the following processes take place? (2 points)

a. Transcription
b. Translation

3. The following is a base sequence on a strand of DNA. When the strand replicates, what is the base sequence on the complementary strand of DNA? (2 points)
AATCGCATACCCGGTCAG

4. Transcribe the following DNA molecule into mRNA: TAACCTGGACTACAAATC. (2points)

5. What is a promoter? (2 points)

6. What is the role of the enzyme DNA polymerase? (2 points)

7. What is the end product of transcription? (2 points)

8. Why would it be impossible to extract DNA from cooked foods? (2 points)

9. Which DNA extraction procedure (warm water versus room temperature water) produced a greater quantity of DNA? Explain why the results turned out the way that they did. (6 points)
10. Provide the amino acid sequence for DNA template cards 1 through 5 (from Procedure 4 in the lab)? (10 points)
a. DNA template card # 1:
b. DNA template card # 2:
c. DNA template card # 3:
d. DNA template card # 4:
e. DNA template card # 5:

11. What is an exon? (2 points)

12. What three molecules are needed for the process of translation? (3 points)
a.
b.
c.
13. What are the building blocks of proteins called? (2 points)

14. List the three stop codons. (3 points)
a.
b.
c.
15. Provide the amino acid sequence for DNA template cards 6 through 10 (from Procedure 4). (10 points)

a. DNA template card # 6:
b. DNA template card # 7:
c. DNA template card # 8:
d. DNA template card # 9:
e. DNA template card # 10:

16. Define the following terms: (2 points)
a. Point mutation
b. Frameshift mutation

17. Name the type of mutation that occurred below. (2 points)
Original strand of DNA: CTAGGCCTAACTGCC
Replicated strand of DNA: CTAGGCCAAACTGCC

18. Provide the amino acid sequence for DNA template cards 5 and 11 through 14 (from Procedure 4). (10 points)
a. DNA template card #5:
b. DNA template card # 11:
c. DNA template card # 12:
d. DNA template card # 13:
e. DNA template card # 14:
19. DNA template cards 11 through 14 represent mutations that occurred in template card
five. Review the amino acid sequences for cards 5 and 11 through 14 and answer the following: (10 points)
a. What type of mutation occurred in cards 11 and 12?
b. Did the mutation in card 11 result in a change in the protein synthesized?
c. Did the mutation in card 12 result in a change in the protein synthesized?
d. What type of mutation occurred in cards 13 and 14?
e. Would the mutations that occurred in cards 13 and 14 result in a change in the protein synthesized?

20. A base deletion of base eight (frameshift mutation) occurs in the following nucleotide sequence: CTCAATGAAGGCCTA. (4 points)
a. Write the codons for the nucleotide sequence.
b. Write the codons for the nucleotide sequence following the base deletion.
21. (Application) How might the information gained from this lab pertaining to protein synthesis be useful to a student employed in a healthcare related profession? (20 points)