Let's break down your questions step by step.
Original DNA Sequence
Original DNA Sequence: T A C A C C T T G G C G A C G A C T
mRNA Sequence:
To transcribe the DNA to mRNA, we replace each DNA base with its complementary RNA base:
- A → U
- T → A
- C → G
- G → C
Thus, the mRNA sequence would be:
mRNA Sequence: A U G U G G A A C C G C U G C U G A
Amino Acid Sequence:
To translate the mRNA to an amino acid sequence, we read the mRNA in codons (triplets of nucleotides):
- A U G → Methionine (Met)
- U G G → Tryptophan (Trp)
- A A C → Asparagine (Asn)
- C G C → Arginine (Arg)
- U G C → Cysteine (Cys)
- U G A → Stop codon (translation ends here)
So, the amino acid sequence is:
Met-Trp-Asn-Arg-Cys
Mutated DNA Sequence #5
Mutated DNA Sequence #5: T A C A C C T T G G G A C G A C T
- Circle the change: The third codon has changed from CCT (which codes for Proline) to GGG (which codes for Glycine).
mRNA Sequence for Mutated DNA:
Again, using the same transcription method:
mRNA Sequence: A U G U G G A A C C C U G C U G A
Amino Acid Sequence for Mutated DNA:
- A U G → Methionine (Met)
- U G G → Tryptophan (Trp)
- A A C → Asparagine (Asn)
- C C C → Proline (Pro)
- U G C → Cysteine (Cys)
- U G A → Stop codon (translation ends here)
So, the amino acid sequence for the mutated DNA is:
Met-Trp-Asn-Pro-Cys
Effects of Mutations:
This mutation caused a change in the amino acid sequence (Proline to Glycine). There will likely be effects since amino acids can differ substantially in their properties and how they contribute to protein structure and function.
Type of Mutation:
This mutation is a missense mutation because it results in a change in a single amino acid in the protein sequence.
Additional Questions
-
Which type of mutation is responsible for new variations of a trait?
- Answer: Point mutations or frame shift mutations can create new variations of traits, but point mutations are more commonly associated with single, specific changes.
-
Which type of mutation does not result in an abnormal amino acid sequence?
- Answer: Silent mutations do not result in an abnormal amino acid sequence; these mutations change a codon to one that encodes for the same amino acid.
-
Which type of mutation stops the translation of an mRNA molecule?
- Answer: Nonsense mutations; they introduce a premature stop codon, leading to truncated proteins.
Sickle Cell Anemia
Normal Hemoglobin DNA: C A C G T A G A C T G A G G A C T C ...
Normal Hemoglobin mRNA: G U G C A U C U G A C U C C U G A ...
Normal Hemoglobin AA Sequence: Valine - Histidine - Leucine - Glutamic Acid - Proline ...
Sickle Cell Hemoglobin DNA: C A C G T A G A C T G A G G A C A C ...
Sickle Cell Hemoglobin mRNA: G U G C A U C U G A C U C C U G U ...
Sickle Cell Hemoglobin AA Sequence: Valine - Histidine - Leucine - Valine - Glutamic Acid - Proline ...
Type of Mutation:
This is a missense mutation, specifically a substitution mutation, which alters a single amino acid (glutamic acid to valine) in the sequence of the hemoglobin protein. This alteration leads to significant changes in the properties of hemoglobin, causing the RBCs to sickle under low oxygen conditions.
1 answer