LABORATORY REVIEW
MOLECULAR BIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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A nucleotide or group of nucleotides is inserted into the wrong location in the DNA. This changes the order in which the nucleotides are “read” and results in the synthesis of an incorrect amino acid sequence.
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A nucleotide or group of nucleotides is deleted from the DNA. This changes the order in which the nucleotides are “read” and results in the synthesis of an incorrect amino acid sequence.
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An incorrect nucleotide is substituted for the correct nucleotide. This changes one codon in the gene sequence. This results in a change in one amino acid in the protein. This change in one amino acid changes the overall shape/function of the protein.
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Several incorrect nucleotides are substituted for their correct counterparts. This changes several of the amino acids in the protein and results in a protein that is misshapen and not functional.
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Detailed explanation-1: -There are three types of DNA Mutations: base substitutions, deletions and insertions. Single base substitutions are called point mutations, recall the point mutation Glu—–> Val which causes sickle-cell disease.
Detailed explanation-2: -Sickle cell disease (SCD) is characterized by a single point mutation in the seventh codon of the -globin gene.
Detailed explanation-3: -As mentioned, sickle-cell anemia is the result of a change in a single nucleotide, and it represents just one class of mutations called point mutations.
Detailed explanation-4: -Sickle cell anemia results from the single amino acid substitution of valine for glutamic acid in the beta-chain owing to a nucleotide defect that causes the production of abnormal beta-chains in hemoglobin S.
Detailed explanation-5: -For example, sickle cell anemia is caused by a substitution in the beta-hemoglobin gene, which alters a single amino acid in the protein produced.