Sickle cell anaemia is a genetic disease that affects red blood cells in the body. It is due to a mutation on the Hb gene which codes for a polypeptide of 146 amino acids which is part of haemoglobin (haemoglobin is an important protein component in red blood cells). In sickle cell anaemia the codon GAG found in the normal Hb gene is mutated to GTG. This is called a base substitution mutation as adenine (A) is replaced by thymine (T). This means that when the mutated gene is transcribed, a codon in the messenger RNA will be different. Instead of the normal codon GAG, the messenger RNA will contain the codon GUG. This in turn will result in a mistake during translation. In a healthy individual the codon GAG on the messenger RNA matches with the anticodon CUC on the transfer RNA carrying the amino acid glutamic acid. However, if the mutated gene is present then GUG on the messenger RNA matches with the anticodon CAC on the transfer RNA which carries the amino acid valine. So the base substitution mutation has caused glutamic acid to be replaced by valine on the sixth position on the polypeptide. This results in haemoglobin S being present in red blood cells instead of the normal haemoglobin A. This has an effect on the phenotype as instead of normal donut shaped red blood cells being produced some of the red blood cells will be sickle shaped. As a result these sickle shaped red blood cells cannot carry oxygen as efficiently as normal red blood cells would. However, there is an advantage to sickle cell anemia. The sickle cell red blood cells give resistance to malaria and so the allele Hbs on the Hb gene which causes sickle cell anemia is quite common in parts of the world where malaria is found as it provides an advantage over the disease
Not at all. mRNA is not involved in DNA replication as it is involved in transcription and translation.
The wrong amino acid chain will be produced
One gene codes for (or provides the recipe) for the creation of one polypeptide through transcription and translation.
DNA replication
transcription... We are studying DNA and its processes in my Biology class
If you mean in DNA transcription: 1. have no effect 2. produce a mutation 3. cause death of the cell in which this is happening
mutation
a mutation in a gene that does not affect the downstream genes in an operon. ie. a polar mutation is one that DOES affect the transcription or translation of genes in the same operon downstream of your gene of interest.
transcription and translation
Transcription
whenever an amino acid is missing it means there is deletion mutation. deletion mutations have deleterious effects on the transcription and translation as the reading frame is disturbed causing a change in gene.
A mutation in DNA yields mutated mRNA (via transcription) which yields mutated proteins (via translation). Mutated proteins contain different amino acids (whether it be in a different order, shorter, longer, or missense).
transcription
Transcription
during translation
A possible effect on an error during transcription is that a nonfunctioning protein will be produced. The protein would be made of the wrong amino acids chain will be produced (and wrong shape). The wrong protein will be produced. the wrong amino acid chain will be produced
IF only you weren't here for apex! you're welcome for making your day!