BIOL 1408 RC Antisense DNA Strand Into The MRNA Strand Gene Expression Lab Report

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xhxvfun

Science

BIOL 1408

Richland College

BIOL

Description

I have attached the genetic codes list and the worksheet.

Transcribe the "gene" at the top of the worksheet using the genetic code provided in the handout or the one in your textbook. Write your transcribed mRNA molecule directly underneath the "gene" on your worksheet in large letters (so you have room to translate underneath it). Transcribe the gene using complementary base-pairing rules and write the correct mRNA (with 5' and 3' labels as directed) below the gene. Make sure your RNA nucleotides line up under each DNA nucleotide and that your mRNA contains U, not T when pairing with A. Label this new mRNA with a 5' on the left side and the 3' on the right side because your DNA gene was shown 3' to 5' and all nucleic acids pair up in an anti-parallel (opposing directions) way.

Step 4: Use the genetic code key to translate your mRNA. If you transcribed correctly, the first 3 nucleotides on your mRNA should be A-U-G, which translates (using the genetic code) to the amino acid Methionine (often abbreviated Met or just "M"). This A-U-G is also the start codon that tells you to get started translating. For each amino acid, write down only the one-letter abbreviation (so "M" for methionine).

Demonstration of how methionine is the first amino acid translated. The text explanation in this image is the same as the text provided above the image.

PAY CAREFUL ATTENTION: The first letter is NOT always the correct one-letter abbreviation because some amino acids start with the same letter. For example, because glycine's one-letter abbreviation is "G", glutamate's one-letter abbreviation cannot be "G" so they made it "E" instead!

Step 5: Continue translating until you encounter a STOP codon (see genetic code key for which codons tell you to stop). When you encounter the stop codon, immediately stop translating even if there are more nucleotides in your mRNA after that stop. The stop codon signals to the cell that translation is over and the finished protein gets released to do its job. Make sure you have written your translation using the one-letter abbreviations, not the 3-letter abbreviations (i.e. write "M" for methionine, not "Met").

If you did the translation correctly, your finished "protein" written in the one-letter abbreviations should spell out an actual English word that begins with the letter M (since all translations begin with the M encoded by the start codon).

Once you're sure you translated the original gene correctly, we're going to see what happens if we mutate the gene by making just one single nucleotide change in our DNA.

Step 6: The next section of your worksheet provides you with the SAME gene after it has been exposed to UV rays from too much sunlight. Your cells failed to repair all the DNA damage caused by the UV rays, so this gene now has a single point mutation (highlighted in bold). Transcribe this mutated version of the gene to make the new version of the mRNA that your cells will make from now on.

Step 7: Translate this new, mutated gene's mRNA to see what effect the mutation had on your protein. Remember to write the translation using the one-letter abbreviations for each amino acid. Does it still spell out an actual English word? Is it the same word?

Step 8: Of the effects caused by "point mutations" in your DNA (single or a couple nucleotides being changed), proteins can exhibit: silent mutations, missense mutations, nonsense mutations and frameshift mutations. Which type of protein effect did this mutation cause? The 3rd section of your worksheet is the original gene again, but this time with a different mutation (highlighted in bold again).

Step 6: Transcribe this next mutated version of the gene to make another different version of the mRNA.

Step 7: Translate this next mutated gene's mRNA to see what effect the mutation had on your protein. Again write the final translation using the one-letter abbreviations for each amino acid. Does it still spell out an actual English word? Is it the same word as the original gene?

Step 8: Which type of mutation effect did this change cause?

After completing the worksheet, answer the questions that are listed below.

Q1;- Write a paragraph describing what you did, what you observed (your data/results), and what you concluded. This should be a summary of the entire lab, with:

A) at least 1 complete sentence describing the experimental procedure (what you did)

B) at least 1 complete sentence describing what you saw happen (observations and results)

C) at least 1 complete sentence describing what your results meant in relation to the concept this lab addressed (conclusions)

Q2;- For your original gene and mRNA, what protein (sequence of amino acids) resulted from your translation? Remember to write it here using the one-letter abbreviations so it shows the word that you found in your translation!

Q3;- When you transcribed and translated the first point mutation, what protein (sequence of amino acids) resulted from your translation? Remember to write it here using the one-letter abbreviations for comparison to the original translation above.

Q4;- The effect of the first mutation on the translated "protein" would best be described as:

Q5;- When you transcribed and translated the second point mutation, what protein (sequence of amino acids) resulted from your translation? Remember to write it here using the one-letter abbreviations.

Q6;- The effect of the second mutation on the translated "protein" would best be described as:

Q7;- In general, frameshift and nonsense mutations tend to have the greatest effect on protein function, and therefore, a person's overall health and wellness. WHY do you think having a frameshift or nonsense mutation is more likely to have a severe effect on a person's health than having a silent or missense mutation?

Unformatted Attachment Preview

Second Nucleotide in Codon For this genetic code key, read each codon from the CENTER OUTWARD. The letters on the outside of the circle are the one-letter amino acid abbreviations. Third Nucleotide in Codon First Nucleotide in Codon Genetic Codes: BIOL 1408 Online - LAB 8: Gene Expression Gene Expression Worksheet Your online Lab 8 page in eCampus provides instructions to help you complete this worksheet. This is your DNA “gene” ready for expression: 3’ - T A C T A G T T G T G C A T T - 5’ Your mRNA: Your protein: Is it an actual word when you used the one-letter abbreviations? If not, go back and double check your transcription and translation! This is the first mutated version of the original DNA “gene”: 3’ - T A C T A T T T G T G C A T T - 5’ Your mRNA: Your protein: What type of effect did this point mutation have on the protein? ______________ This is the second mutated version of the original DNA “gene”: 3’ - T A C T A G T T G A G C A T T - 5’ Your mRNA: Your protein: What type of effect did this point mutation have on the protein? _______________
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Explanation & Answer

Here you go! My answers are in bold on the genetic worksheet word document.


Q1. In this experiment I transcribed the anti-sense DNA strand into the mRNA strand, then
translated the mRNA strand into the protein sequence. Then, after the DNA was exposed to
UV light and a mutation occurred, I transcribed and translated the mutated DNA strand into
the new corresponding mRNA and protein. Finally, I transcribed and translated a final
mutated DNA strand into the corresponding new mRNA and protein, and observed what
changes occurred in the mRNA and protein after e...


Anonymous
Excellent resource! Really helped me get the gist of things.

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