This exercise is designed to help you understand better how DNA exists as a doub

Question

This exercise is designed to help you understand better how DNA exists as a double strand and how it can code for a protein and the consequences of variation (mutation) of the DNA on the protein that it codes for. If you are unsure how to do this exercise you should look to your transcription and translation lectures for guidance. The DNA sequence I is the anti-sense strand (template), the other 4 sequences are the sense (non template) strands. Do the following exercise: 1. Write out the sense DNA strand for sequence 1 and indicate polarity 1-Template 3-TAC TCG AAC TCC CGC CCT GGG ACG TAC ATT-5, 2. Complete the following exercises: a. Transcribe each DNA (lI-V) sequence into RNA and write out the RNA sequence b. Translate each RNA sequence generated in section (a) into a (string of amino acids) using the genetic code attached in page 2. out the protein sequence (The arrangement/spacing of the sequence indicates how the codons should be read). protein Write Look at the DNA sequences of II and III and compare the DNAs. Look at the proteins sequences that they code for. What do you notice about the DNA sequences? What do you notice about the protein sequences? Is it interesting? Why is this interesting? c. d. Compare DNA sequence II to sequence IV, how are they different? Do the same thing with sequence II and sequence V. Wha of the differences in the DNA sequences. Why is it interesting if you compare it to the answer to question 2c? t are the consequences 11 sense 5,-ATG TCA CTA CGC GCA GGC CCA TGT ATG TAG-3, III sense 5'- ATG AGC TTG AGA GCT GGT CCT TGC ATG TAG-3 iv sense 5,-ATG TGA CTA CGC GCA GGC CCA TGT ATG TAG -3, v sense5- ATG CTC ACT ACG CGC AGG CCC ATG TAT GTA -3'

Explanation / Answer

Given template DNA sequence: 3'-TACTCGAACTCCCGCCCTGGGACGTACATT-5'
Complementary sequence: 5'-ATGAGCTTGAGGGCGGGACCCTGCATGTAA-3'

Sequence II: 5'-ATGTCACTACGCGCAGGCCCATGTATGTAG-3'
RNA sequence: 5'-AUGUCACUACGCGCAGGCCCAUGUAUGUAG-3'
Protein sequence: NH2-MSLRAGPCM-COOH

Sequence III: 5'-ATGAGCTTGAGAGCTGGTCCTTGCATGTAG-3'
RNA sequence: 5'-AUGAGCUUGAGAGCUGGUCCUUGCAUGUAG-3'
Protein sequence: NH2-MSLRAGPCM-COOH

Sequence IV: 5'-ATGTGACTACGCGCAGGCCCATGTATGTAG-3'
RNA sequence: 5'-AUGUGACUACGCGCAGGCCCAUGUAUGUAG-3'
Protein sequence: NH2-M-stop-LRAGPCM.-COOH

Sequence V: 5'-ATGCTCACTACGCGCAGGCCCATGTATGTA-3'
RNA sequence: 5'-AUGCUCACUACGCGCAGGCCCAUGUAUGUA-3'
Protein sequence: NH2-MLTTRRPMYV-COOH

Sequences II and III code for the same protein sequence even though they have different DNA sequences. This is due to the redundancy of the genetic code.
There is a nonsense mutation in the sequence IV compared to sequence II.
There is single basepair deletion in the sequence IV compared to sequence II. This resulted in frameshift and production of a completely different protein.

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