Question

sickle cell anemia is the result of a type of mutation in the gene that causes these red blood cells to become hemoglobin carries oxygen in your red bloods cells. the mutation causes these sickled cells tend to get stuck in blood vessels, causing sickle - shaped when they release their oxygen. the 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 mutatior 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 4. what type of mutation is this? please explain why.

Explanation:

To determine the mutation type, we first transcribe the DNA to mRNA. For normal DNA \(CACTGAGGACTC\), mRNA is \(GUGACUCCUGAG\). For sickle - cell DNA \(CACTGAGGACAC\), mRNA is \(GUGACUCCUGUG\). Then, using the codon table, the normal mRNA \(GAG\) codes for glutamic acid (\(Glu\)), and the mutated mRNA \(GUG\) codes for valine (\(Val\)). Since only one base (\(T\) to \(A\) in DNA, corresponding to \(GAG\) to \(GUG\) in mRNA) is changed, causing a single amino - acid substitution, it is a missense mutation.

Answer:

This is a missense mutation. One base in the DNA (the \(T\) in the normal DNA strand corresponding to the codon for the amino - acid is changed to \(A\) in the sickle - cell DNA). This leads to a change in the mRNA codon (\(GAG\) to \(GUG\)) and thus a substitution of one amino - acid (glutamic acid to valine).