Lab 6 DNA and RNA BIO101L

DNA and RNA

Pre-Lab Questions

1. Arrange the following molecules from least to most specific with respect to the original nucleotide sequence: RNA, DNA, Amino Acid, Protein
2. Identify two structural differences between DNA and RNA.
3. Suppose you are performing an experiment in which you must use heat to denature a double helix and create two single-stranded pieces. Based on what you know about nucleotide bonding, do you think the nucleotides will all denature at the same time? Use scientific reasoning to explain why.

Experiment 1: Coding

Procedure:

1. With the red, blue, yellow, and green beads, you will use three color codes for each of the following letters (codon). For instance, the code for codon E is RGB or red-green-blue.

2. Using this code, align the beads corresponding to the appropriate letter to write the following sentence (don’t forget start, space, and stop):
3. a) The mouse likes most cheese
4. b) How many beads did you use?

There are multiple ways your cells can read a sequence of DNA and build slightly different proteins from the same strand. We will not go through the process here, but as an illustration of this “alternate splicing”, remove codons (beads) 52 – 66 from your sentence above.

1. c) What does the sentence say now? (re-write the entire sentence)

Mutations are simply changes in the sequence of nucleotides. There are three ways this occurs:

1. Change a nucleotide(s)
2. Remove a nucleotide(s)
3. Add a nucleotide(s)
4. Using the sentence “The mouse likes most cheese.:
5. Change the 24th bead to a different color. What letter was affected: Re-write the sentence (in codons): Does the new sentence make sense? If not, write the words that still make sense (using the code):
6. Replace the 24th bead and remove the 20th bead (remember what was there). What letter was affected: Re-write the sentence (in codons): Does the new sentence make sense? If not, write the part that does make sense (using the code):
7. Replace the 20th bead and add one between bead numbers 50 and 51. What was affected: Re-write the sentence (in codons): Does the new sentence make sense? If not, write the part that does make sense (using the code):
8. In 3. a (above) you mutated one letter. What role do you think the redundancy of the genetic code plays in this type of change?
9. Based on your observations, why do you suppose the mutations we made in 3.b and 3.c are called frameshift mutations?
10. Which mutations do you suspect have the greatest consequence? Why?

Experiment 2: Transcription and Translation

Procedure *Note: In this experiment, Regular beads are used as nucleotides and Pop-it beads are used as amino acids. Use the following sentence and code for this experiment: I like to eat apples.

1. Write the sentence using the beads, and then write the coded sentence in the space below.
2. How many beads did you use?
3. Assign one Pop-It® bead to represent each codon. You do not need to assign a Pop-It® bead for the start, stop, and space regions. These will be your amino acids. Then, connect the Pop-It® beads to build the chain of amino acids that code for your sentence (leave out the start, stop, and space regions).
4. How many different amino acids did you use?
5. How many total amino acids did you use?

Experiment 3: DNA Extraction

Post-Lab Questions

1. Insert a picture of your final DNA extraction. Make sure your name and access code are handwritten in the background.
2. What is the texture and consistency of the DNA?
3. Why did we use salt in the extraction solution?
4. Is the DNA soluble in the aqueous solution or alcohol?
5. What else might be in the ethanol/aqueous interface? How could you eliminate this?
6. Which DNA bases pair with each other and how many hydrogen bonds are shared by each pair?
7. How is information to make proteins passed on through generations?
8. What was the purpose of the detergent and ethanol in this experiment?