Question

original dna sequence: tacaccttggcgacgact...
mrna sequence:
amino acid sequence:

mutated dna sequence #5 tacaccttgggacgact...
whats the mrna sequence? (circle the change)
what will be the amino acid sequence?
will there likely be effects? what type of mutation is this?

1. which type of mutation is responsible for new variations of a trait?
2. which type of mutation does not result in an abnormal amino acid sequence?
3. which type of mutation stops the translation of an mrna molecule?

sickle cell anemia
sickle cell anemia is the result of a type of mutation in the gene that codes for part of the hemoglobin molecule. hemoglobin carries oxygen in your red blood cells. the mutation causes these red blood cells to become stiff & sickle - shaped when they release their oxygen. the sickled cells tend to get stuck in blood vessels, causing pain and increased risk of stroke, blindness, damage to the heart & lungs, and other conditions.
— analyze the dna strands below to determine what amino acid is changed and what type of mutation occurred

normal hemoglobin dna cacgtagactgaggactc...
normal hemoglobin mrna
normal hemoglobin aa sequence

sickle cell hemoglobin dna cacgtagactgaggacac...
sickle cell hemoglobin mrna
sickle cell hemoglobin aa sequence

1. what type of mutation is this? please explain why.

Explanation:

Step1: Transcribe original DNA to mRNA

In transcription, DNA's A pairs with mRNA's U, T with A, G with C and C with G. For original DNA sequence TACACCTTGGCGACGACT, the mRNA sequence is AUGUGGAACCGCUGCUGA.

Step2: Translate mRNA to amino - acid sequence

Using the genetic code, AUG is Methionine (Met), UGG is Tryptophan (Trp), AAC is Asparagine (Asn), CGC is Arginine (Arg), UGC is Cysteine (Cys), UGA is a stop codon. So the amino - acid sequence is Met - Trp - Asn - Arg - Cys - stop.

Step3: Transcribe mutated DNA #5 to mRNA

For mutated DNA sequence TACACCTTGGGACGACT, the mRNA sequence is AUGUGGAACCCUGCUGA. The change is in the 9th base where mRNA has C instead of G (circled in the mRNA sequence).

Step4: Translate mutated mRNA to amino - acid sequence

AUG is Met, UGG is Trp, AAC is Asn, CCC is Proline (Pro), UGC is Cys, UGA is stop. So the amino - acid sequence is Met - Trp - Asn - Pro - Cys - stop. This is a missense mutation as one amino - acid (Arg is replaced by Pro). There will likely be effects as the amino - acid sequence is changed which can affect protein function.

Step5: Answer general mutation questions

1. Point mutations (specifically base - substitution mutations like missense, nonsense, silent) can be responsible for new variations of a trait as they change the DNA sequence which can change the protein produced.
2. Silent mutations do not result in an abnormal amino - acid sequence as they change the DNA sequence in a way that the same amino - acid is still coded for.
3. Nonsense mutations stop the translation of an mRNA molecule as they introduce a premature stop codon.

Step6: Analyze sickle - cell anemia mutations

For normal hemoglobin DNA CACTAGACTGAGGACTC, the mRNA is GUGAUCUGACUCCUGAG. The amino - acid sequence is Val - Ile - Asp - Ser - Leu - Glu.
For sickle - cell hemoglobin DNA CACGTAGACTGAGGACAC, the mRNA is GUGCAUCUGACUCCUGUG. The amino - acid sequence is Val - His - Asp - Ser - Leu - Val. The amino - acid that is changed is Glu to Val at the 6th position. This is a missense mutation because a single amino - acid in the protein is changed due to a single - base substitution in the DNA.

Answer:

Original DNA Sequence: TACACCTTGGCGACGACT
mRNA Sequence: AUGUGGAACCGCUGCUGA
Amino Acid Sequence: Met - Trp - Asn - Arg - Cys - stop

Mutated DNA Sequence #5: TACACCTTGGGACGACT
mRNA sequence: AUGUGGAACCCUGCUGA (change is 9th base C instead of G)
Amino acid sequence: Met - Trp - Asn - Pro - Cys - stop
Will there likely be effects? Yes
What type of mutation is this? Missense mutation

1. Point mutations (base - substitution mutations)
2. Silent mutations
3. Nonsense mutations

Normal hemoglobin DNA: CACTAGACTGAGGACTC
Normal hemoglobin mRNA: GUGAUCUGACUCCUGAG
Normal hemoglobin AA sequence: Val - Ile - Asp - Ser - Leu - Glu

Sickle cell hemoglobin DNA: CACGTAGACTGAGGACAC
Sickle cell hemoglobin mRNA: GUGCAUCUGACUCCUGUG
Sickle cell hemoglobin AA sequence: Val - His - Asp - Ser - Leu - Val
What type of mutation is this? Missense mutation. Reason: Single - base substitution in DNA causes a single amino - acid change (Glu to Val) in the hemoglobin protein.