Homework Answers
1) In sickle cell anemia, there is point mutation ( missing sense mutation) from T to A. This will replace beta chain N terminal 6 position glutamine to valine. As glutamate is a polar amino acid , is replaced by non polar amino acid valine. This causes a marked decreased solubility of HbS in deoxygenated form ( T form). However solubility of oxyhaemoglobin HbS is unaffected. This replacement of glutamate to valine leads to decrese in solubility of Hbs as well as their polymerization in deoxy form which lead to precipitation.
2) substitution of aljne for glutamate results in to sticky patches on the outer surface of beta chain. There sticky patches present on oxy as well as deoxy Hbs. But these patches are absent on HbA .
There are corresponding receptor for sticky patches on alpha subunit of other deoxy HbS. So patches of one deoxy Hbs , polymerize with receptor of othe deoxyHbs. This polymerization continues lead to formation of long aggregates of deoxyHbS. This polymerization leads to long fibrous like structure formation. As these fibers precipitate, due to their stiffness they distort RBC and convert them in to sickle shape and their lysis.
If this Hbs is maintained in to oxy form than this polymerization can be prevented due to absence of corresponding receptor on alpha chain.
Mechanism of polymerization has been explained below
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mutation: sickle cell
Explain in terms of the listed mutation and structural elements, what causes polymerization...
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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. Recall that 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...
Sickle cell anemia is a genetic disease resulting from a single amino acid substitution (glutamate to...
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A mutation in one of the hemoglobin genes causes sickle cell anemia. The sickle cell allele,...
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Use the following information to answer the next two questions. Sickle cell anemia is a disease...
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Sickle-cell anemia is caused by a single point mutation in the hemoglobin of human red blood cells. It is a recessive gene. People who have sickle cell anemia are homozygous recessive and suffer terribly from this disorde
Sickle-cell anemia is caused by a single point mutation in the hemoglobin of human red blood cells. It is a recessive gene. People who have sickle cell anemia are homozygous recessive and suffer terribly from this disorder. Now I have stated in lecture that mutations are neither good nor bad. Rather it depends on how the mutation effects the survival of the species. If the mutation harms the survival of the species it is bad, if it helps the survival...
A mutation in one of the hemoglobin genes causes sickle cell anemia. The sickle cell allele,...
A mutation in one of the hemoglobin genes causes sickle cell anemia. The sickle cell allele, S, severely reduces fitness in people who are homozygotes, SS. In contrast, people with at least one normal hemoglobin allele, A, do not suffer the effects of sickle cell anemia, even if the individual is a heterozygote, AS. Interestingly, in areas with high rates of malaria, a single Sallele confers some resistance to malarial infection. Suppose there is a population with the observed and...
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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. Recall that 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...
A mutation in one of the hemoglobin genes causes sickle cell anemia. The sickle cell allele, S, severely reduces fitness in people who are homozygotes, SS. In contrast, people with at least one normal hemoglobin allele, A, do not suffer the effects of sickle cell anemia, even if the individual is a heterozygote, AS. Interestingly, though, in areas with a high rate of malaria, heterozygotes that carry the sickle cell allele have a higher fitness than do individuals that are...
A mutation in one of the hemoglobin genes causes sickle cell anemia. The sickle cell allele, S, severely reduces fitness in people who are homozygotes, SS. In contrast, people with at least one normal hemoglobin allele, A, do not suffer the effects of sickle cell anemia, even if the individual is a heterozygote, AS. Interestingly, in areas with high rates of malaria, a single Sallele confers some resistance to malarial infection. Suppose there is a population with the observed and...
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