DNA Mutation Analysis Worksheet for Biology Class

Final Answer:
Original DNA: T A C A C C T T G G C G A C G A C T
mRNA: A U G U G G A A C C G C U G C U G A
Amino Acid: Met–Trp–Asn–Arg–Cys–Stop

Mutated #1: T A C A T C T T G G C G A C G A C T
mRNA: A U G U A G A A C C G C U G C U G A
Amino Acid: Met–Stop
Effects: Yes — premature stop codon → truncated protein
Mutation type: Nonsense mutation

Mutated #2: T A C G A C C T T G G C G A C G A C T
mRNA: A U G C U G G A A C C G C U G C U G A
Amino Acid: Met–Leu–Glu–Pro–Leu
Effects: Yes — amino acid change (Trp→Leu, Asn→Glu, Arg→Pro, Cys→Leu); no stop codon shift
Mutation type: Insertion (1 extra base: G after position 3) → frameshift

Mutated #3: T A C A C C T T A G C G A C G A C T
mRNA: A U G U G G A A U C G C U G C U G A
Amino Acid: Met–Trp–Asn–Arg–Cys–Stop
Effects: No — same amino acids (TTA → UAA? Wait—check: DNA TTA → mRNA AAU = Asn; original TTC → mRNA AAG = Lys? Let’s correct carefully.)
Actually: Original DNA 7–9 = T T G → mRNA A A C = Asn
Mutated #3 DNA 7–9 = T T A → mRNA A A U = Asn → same!
So: mRNA: A U G U G G A A U C G C U G C U G A
Amino acids: Met–Trp–Asn–Arg–Cys–Stop
Effects: No effect (silent at amino acid level — though codon changed, same amino acid)
Mutation type: Silent mutation

Mutated #4: T A C A C C T T G G C G A C T A C T
mRNA: A U G U G G A A C C G C U G A U G A
Amino Acid: Met–Trp–Asn–Arg–Stop
Effects: Yes — earlier stop (at 5th codon instead of 6th) → shorter protein
Mutation type: Nonsense mutation (C→T at position 14 changes CGA → UGA stop)

Mutated #5: T A C A C C T T G G G A C G A C T
mRNA: A U G U G G A A C C C U G C U G A
Amino Acid: Met–Trp–Asn–Pro–Cys–Stop
Effects: Yes — Arg (CGC) → Pro (CCU) at 4th position
Mutation type: Missense mutation (single base change: G→A at position 10 changes GGC → GAC? Wait—let’s align:
Original DNA pos 10–12: G G C → mRNA C C G = Pro? No—wait, standard codon table:
DNA template strand is given (since TAC → AUG start), so we transcribe complement:
A ↔ U, T ↔ A, C ↔ G, G ↔ C.
So original DNA: T A C A C C T T G G C G A C G A C T
→ mRNA: A U G U G G A A C C G C U G C U G A
Codons: AUG (Met), UGG (Trp), AAC (Asn), CGC (Arg), UGC (Cys), UGA (Stop)

Mutated #5: T A C A C C T T G G G A C G A C T
Length is 15 vs original 16 — missing one base? Count:
Original: 16 bases
#5: T A C A C C T T G G G A C G A C T → 15 bases → deletion of one base (position 13: G missing?)
Let’s index:
1 T,2 A,3 C,4 A,5 C,6 C,7 T,8 T,9 G,10 G,11 C,12 G,13 A,14 C,15 G,16 A,17 C,18 T? Wait—original shown has 16 letters: “TACACCTTGGCGACGACT” = 16.
#5: “TACACCTTGGGACGACT” = 15 → missing one base (the 12th? Original positions:
1 T
2 A
3 C
4 A
5 C
6 C
7 T
8 T
9 G
10 G
11 C
12 G
13 A
14 C
15 G
16 A
17 C
18 T? Actually count: T-A-C-A-C-C-T-T-G-G-C-G-A-C-G-A-C-T = 18 bases. Yes, 18.

Original: 18 bases
#5: T A C A C C T T G G G A C G A C T = 17 → deletion of one base (the 11th C? Let's compare:)

Original: 1 T 2 A 3 C 4 A 5 C 6 C 7 T 8 T 9 G 10 G 11 C 12 G 13 A 14 C 15 G 16 A 17 C 18 T
#5: 1 T 2 A 3 C 4 A 5 C 6 C 7 T 8 T 9 G 10 G 11 G 12 A 13 C 14 G 15 A 16 C 17 T
→ So at position 11, original C is replaced by G, and position 12 onward shifted? Actually #5 has 17 letters — likely a deletion of one base (e.g., position 12 G omitted), but written as GGG instead of GGC — so it’s a substitution: C→G at position 11, making GGC → GGG in DNA, which is mRNA: CC G → CC C → Pro → Pro (same). Wait: DNA 10-12: G G C → mRNA C C G = Pro
#5 DNA 10-12: G G G → mRNA C C C = Pro → still Pro. But then next: original 13-15: A C G → U G C = Cys
#5 13-15: A C G → same. Hmm.

Better to recompute each precisely:

We’ll use DNA template strand → mRNA = complement (A↔U, T↔A, C↔G, G↔C).

Original DNA (18 nt):
T A C A C C T T G G C G A C G A C T
mRNA:
A U G U G G A A C C G C U G C U G A
→ Codons:
1. AUG = Met
2. UGG = Trp
3. AAC = Asn
4. CGC = Arg
5. UGC = Cys
6. UGA = Stop

Now Mutated #1: T A C A T C T T G G C G A C G A C T
Compare: position 5: C→T
DNA: T A C A T C T T G G C G A C G A C T
mRNA: A U G U A G A A C C G C U G C U G A
Codons: AUG (Met), UAG (Stop) → rest irrelevant
→ Nonsense.

#2: T A C G A C C T T G G C G A C G A C T
That’s 19 bases — insertion of G after position 3.
DNA: T A C G A C C T T G G C G A C G A C T
mRNA: A U G C U G G A A C C G C U G C U G A
Codons: AUG (Met), CUG (Leu), GAA (Glu), CCG (Pro), CUG (Leu), ... → frameshift → all changed after first codon.

#3: T A C A C C T T A G C G A C G A C T
DNA pos 7–9: T T G → T T A (G→A)
mRNA pos 7–9: AAC → AAU → both Asn → silent.

#4: T A C A C C T T G G C G A C T A C T
DNA pos 14: G → T (or compare: original …A C G A C T; mutated …A C T A C T) → at position 14: G→T, so DNA 13–15: A C G → A C T
mRNA 13–15: UGC → UGA → Stop instead of Cys → nonsense.

#5: T A C A C C T T G G G A C G A C T
17 bases — missing one. Likely deletion of base 12 (G), so DNA: …T T G G [del G] C G… → becomes T T G G G A…
So original codons 4–5: CGC UGC
After deletion at position 12 (G), sequence shifts:
DNA: 1–11: TACACCTTG G
then 12 missing, so 13 A becomes position 12, etc:
New mRNA: AUG UGG AAC CCU GCU GA…
→ Codon 4: CCU = Pro (was CGC = Arg)
Codon 5: GCU = Ala (was UGC = Cys)
Then likely new stop later. So missense + frameshift? Since deletion of 1 base → frameshift.

But the problem likely expects:
#5: mRNA = AUG UGG AAC CCU GCU GA… → amino acids: Met–Trp–Asn–Pro–Ala–…
Effects: Yes
Mutation type: Frameshift (deletion of one nucleotide)

Given standard classroom expectations, here is the clean final answer set:

Original:
mRNA: AUG UGG AAC CGC UGC UGA
Amino: Met–Trp–Asn–Arg–Cys–Stop

#1: mRNA: AUG UAG AAC CGC UGC UGA → Met–Stop → nonsense
#2: mRNA: AUG CUG GAA CCG CUG CUG A → frameshift → insertion
#3: mRNA: AUG UGG AAU CGC UGC UGA → Met–Trp–Asn–Arg–Cys–Stop (silent)
#4: mRNA: AUG UGG AAC CGC UGA → Met–Trp–Asn–Arg–Stop (nonsense)
#5: mRNA: AUG UGG AAC CCU GCU GA… → Met–Trp–Asn–Pro–Ala… (frameshift due to deletion)

So final concise answer:

Original mRNA: AUG UGG AAC CGC UGC UGA
Original amino acids: Met–Trp–Asn–Arg–Cys–Stop

#1: mRNA: AUG UAG AAC CGC UGC UGA; amino acids: Met–Stop; effects: yes; mutation: nonsense
#2: mRNA: AUG CUG GAA CCG CUG CUG A; amino acids: Met–Leu–Glu–Pro–Leu…; effects: yes; mutation: insertion (frameshift)
#3: mRNA: AUG UGG AAU CGC UGC UGA; amino acids: Met–Trp–Asn–Arg–Cys–Stop; effects: no; mutation: silent
#4: mRNA: AUG UGG AAC CGC UGA; amino acids: Met–Trp–Asn–Arg–Stop; effects: yes; mutation: nonsense
#5: mRNA: AUG UGG AAC CCU GCU GA…; amino acids: Met–Trp–Asn–Pro–Ala…; effects: yes; mutation: deletion (frameshift)