Point mutation Flashcard

A point mutation is a change in a single nucleotide base within the DNA or RNA sequence, which can involve substitution, insertion, or deletion of one base pair.

Types include transitions, transversions, nonsense mutations, missense mutations, silent mutations, and frameshift mutations.

A transition mutation is a substitution where a purine base is replaced by another purine, or a pyrimidine is replaced by another pyrimidine.

A transversion mutation involves the substitution of a purine base with a pyrimidine base or vice versa.

A nonsense mutation changes a codon that specifies an amino acid into a stop codon, leading to early termination of protein synthesis.

A missense mutation is a point mutation that changes one amino acid in the protein sequence, potentially altering protein function.

A silent mutation changes the nucleotide sequence but does not alter the amino acid sequence of the protein due to the redundancy in the genetic code.

A frameshift mutation occurs when nucleotides are inserted or deleted, shifting the reading frame of the codons and altering the protein sequence downstream.

Errors during DNA replication can introduce incorrect nucleotides, leading to point mutations.

Mutagens are agents that induce mutations, including physical (e.g., UV light, X-rays) and chemical (e.g., base-altering chemicals) mutagens.

Reactive oxygen species can cause oxidative damage to DNA, leading to base modifications or breaks, which can result in point mutations.

Allele-specific PCR is a variation of PCR that uses primers specific to either the wild-type or mutant allele to detect point mutations.

DNA sequencing determines the exact nucleotide sequence of a DNA segment, identifying single nucleotide variations compared to a reference sequence.

RFLP involves digesting DNA with restriction enzymes; variations in DNA sequence can alter enzyme cutting patterns, revealing point mutations.

Real-time PCR quantifies DNA amplification in real-time using fluorescent markers, allowing detection of specific point mutations during amplification.

Nonsense mutations usually lead to nonfunctional proteins due to premature termination of protein synthesis.

Point mutations can be introduced to correct genetic defects associated with diseases, such as cystic fibrosis and muscular dystrophy.

Point mutations can be used to target and disrupt cancer-related genes, helping to halt cancer progression.

Mutational breeding uses point mutations to develop new crop varieties with improved traits like higher yields, disease resistance, or better nutrition.

Point mutations help understand drug resistance mechanisms and enable the design of more effective drugs and treatment strategies.

Sickle cell anemia is caused by a point mutation in the HBB gene, leading to abnormal hemoglobin and sickle-shaped red blood cells.

Cystic fibrosis is caused by a deletion of three nucleotides in the CFTR gene, leading to a defective CFTR protein.

In sickle cell anemia, a missense mutation replaces glutamic acid with valine, altering hemoglobin structure and causing red blood cells to sickle.

Silent mutations do not alter the protein's amino acid sequence but can affect mRNA stability or expression.

Crohn's disease can result from a frameshift mutation in the NOD2 gene, leading to a truncated protein.

Point mutations provide insights into genetic variations and evolutionary changes, helping scientists trace adaptation and species diversity.