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    Genetics-From genes to protein, mutations.

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    Transcribe and translate EACH of the three following DNA gene sequences. Turn these in using the graphic organizer. The letters represent the DNA N-base sequences of the genes.

    The first is the original gene. The next two are mutations of the original. Note that the changes (mutations) are shown in parenthesis.

    Original Gene sequence 3'-T A C C C T T T A G T A G C C A C T-5

    Mutated gene sequence 1 3'-T A C (G) C T T T A G T A G C C A (T) T-5'

    Mutated gene sequence 2 3'-T A (A) C C T T T A (C) T A G (G) C A C T-5'

    What is the significance of the first and last codons of an mRNA transcript?
    What meaning do these mRNA codons have for protein synthesis?
    Did the mutations result in a change in the final proteins? If so, describe the change.
    In general, why might a change in amino acid sequence affect protein function?

    © BrainMass Inc. brainmass.com October 6, 2022, 2:26 pm ad1c9bdddf
    https://brainmass.com/biology/reading-the-genome-and-gene-expression/genetics-genes-protein-mutations-565576

    SOLUTION This solution is FREE courtesy of BrainMass!

    Part I

    Original DNA Strand:

    3'-T A C C C T T T A G T A G C C A C T-5'

    Transcription (base sequence of RNA):

    5'-AUGGGAAAUCAUCGGUGA-3'

    Translation (amino acid sequence):

    Met-Gly-Asn-His-Arg-Stop

    Mutated gene sequence one:

    3'-T A C G C T T T A G T A G C C A T T-5'

    Transcription (base sequence of RNA):

    5'-AUGCGAAAUCAUCGGUAA-3'

    Translation (amino acid sequence):

    Met-Arg-Asn-His-Arg-Stop

    Mutated gene sequence two:

    3'-T A A C C T T T A C T A G G C A C T-5'
    Transcription (base sequence of RNA):

    5'-AUUGGAAAUGAUCCGUGA-3'

    Translation (amino acid sequence):

    ILE-GLY-ASN-ASP-PRO-STOP

    What is the significance of the first and last codons of an mRNA transcript?
    Explanation:
    The first codon encode the start sequence which is usually methionine.
    The last codon encode the stop codon that is usually signal the stop of the transcript
    What meaning do these mRNA codons have for protein synthesis?
    Explanation:

    The mRNA codons are usually in triplet code that codes for amino acids. There can be different codons that code for the same amino acids.

    Did the two mutations result in a change in the final proteins? If so, describe the change.
    Response/ explanation: yes, in the first mutation, there is a change in one of the amino acid in the final protein from glycine to arginine.

    Met-Gly-Asn-His-Arg-Stop normal
    Met-Arg-Asn-His-Arg-Stop mutated sequence 1

    In mutation two, there is a change in three amino acids. The start codon methionine is change into isoleucine ; the histidine is changed to aspartic acid the arginine is changed to proline.

    In general, why might a change in amino acid sequence affect protein function?

    Explanation:
    A change in amino acid sequence would affect protein function because each protein has a unique amino acid sequence that encode a specific function. Whenever there is a mutation in the amino acid that change the protein sequence. Its function will change because each protein have a different sequence corresponding to each function.

    This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

    © BrainMass Inc. brainmass.com October 6, 2022, 2:26 pm ad1c9bdddf>
    https://brainmass.com/biology/reading-the-genome-and-gene-expression/genetics-genes-protein-mutations-565576

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