What is a Nucleotide?
A
nucleotide is the basic building block of
DNA and
RNA. Each nucleotide consists of three components: a nitrogenous base (adenine, thymine, cytosine, or guanine in DNA; adenine, uracil, cytosine, or guanine in RNA), a five-carbon sugar (deoxyribose in DNA and ribose in RNA), and a phosphate group. Nucleotides link together to form the long chains of DNA and RNA, encoding genetic information.
Substitution: One nucleotide is replaced by another. For example, an adenine (A) might be substituted by a guanine (G).
Insertion: One or more nucleotides are added into the DNA sequence.
Deletion: One or more nucleotides are removed from the DNA sequence.
Silent Mutation: A mutation that does not change the resulting amino acid and thus has no effect on the protein.
Missense Mutation: A mutation that results in a different amino acid being incorporated into the protein, potentially altering its function.
Nonsense Mutation: A mutation that creates a premature stop codon, leading to a truncated and typically nonfunctional protein.
Frameshift Mutation: Caused by insertions or deletions that change the reading frame of the genetic code, often resulting in a completely altered and nonfunctional protein.
Polymerase Chain Reaction (PCR): A method to amplify specific DNA sequences, making it easier to identify mutations.
DNA Sequencing: Determining the exact sequence of nucleotides in a DNA segment to identify any mutations present.
Gel Electrophoresis: A technique that separates DNA fragments by size, allowing for the identification of insertions or deletions.
Cystic Fibrosis: Often caused by a deletion of three nucleotides in the CFTR gene.
Sickle Cell Anemia: Caused by a substitution mutation in the HBB gene, leading to abnormal hemoglobin.
Tay-Sachs Disease: Usually the result of a frameshift mutation in the HEXA gene.
