Question

directions: complete each box below. original dna sequence: t a c a c c t t g g c g a c g a c t mrna sequence: __________ amino acid sequence: ________, ________, ________, ________, ________, ________, ________, ________ mutated dna sequence #1: t a c a t c t t g g c g a c g a c t what’s the mrna sequence? ________ (circle the change) amino acid sequence? ________, ________, ________, ________, ________, ________, ________, ________ is this a point mutation or a frameshift mutation? ________ is this mutation an example of insertion, deletion, or substitution? ________ predict how this mutation will affect the organism: __________

Explanation:

Step1: Transcribe original DNA to mRNA

Original DNA: $T\ A\ C\ A\ C\ C\ T\ T\ G\ C\ G\ A\ C\ G\ A\ C\ T$
mRNA (A↔U, T↔A, C↔G, G↔C): $A\ U\ G\ U\ G\ G\ A\ A\ C\ G\ C\ U\ G\ C\ U\ G\ A$

Step2: Translate original mRNA to amino acids

Use codon table:
$AUG$ = Methionine (Met), $UGG$ = Tryptophan (Trp), $AAC$ = Asparagine (Asn), $GCG$ = Alanine (Ala), $UGC$ = Cysteine (Cys), $UGA$ = Stop
Amino Acid Sequence: Met - Trp - Asn - Ala - Cys - Stop

Step3: Transcribe mutated DNA to mRNA

Mutated DNA: $T\ A\ C\ A\ T\ C\ T\ T\ G\ C\ G\ A\ C\ G\ A\ C\ T$
mRNA: $A\ U\ G\ U\ A\ G\ A\ A\ C\ G\ C\ U\ G\ C\ U\ G\ A$

Step4: Translate mutated mRNA to amino acids

$AUG$ = Met, $UAG$ = Stop
Amino Acid Sequence: Met - Stop

Step5: Classify the mutation

Compare original and mutated DNA: 3rd $C$ → $T$ (single base swap, no frame shift).

Step6: Determine mutation type

Single base swap = point mutation; base substitution.

Step7: Predict organism impact

Early stop codon truncates the protein, likely making it non-functional.

Answer:

Original mRNA Sequence: $A\ U\ G\ U\ G\ G\ A\ A\ C\ G\ C\ U\ G\ C\ U\ G\ A$
Original Amino Acid Sequence: Methionine - Tryptophan - Asparagine - Alanine - Cysteine - Stop
Mutated mRNA Sequence: $A\ U\ G\ U\ A\ G\ A\ A\ C\ G\ C\ U\ G\ C\ U\ G\ A$
Mutated Amino Acid Sequence: Methionine - Stop
Is this a point mutation or a frameshift mutation? Point mutation
Is this mutation an example of insertion, deletion, or substitution? Substitution
Predict how this mutation will affect the organism: The early stop codon will produce a truncated, non-functional protein, which will likely disrupt the normal biological process this protein was involved in, potentially causing harmful phenotypic changes.