Copy_of_4-genetic-mutations

DNA Mutations

Changes in the nucleotide sequence of DNA that can affect gene expression and lead to various types of mutations.

Single-gene Mutations

Mutations that involve changes in the nucleotide sequence of one gene, categorized into point mutations and frameshift mutations.

Point Mutations

Mutations caused by a change in a single base pair within a DNA sequence, often resulting in the substitution of one nucleotide.

Frameshift Mutations

Mutations that result from the insertion or deletion of nucleotides not divisible by three, leading to a change in the reading frame.

Mutagens

Substances or events that increase the rate of mutations.

Silent Mutations

Mutations that do not change the amino acid sequence of a protein.

Missense Mutations

Mutations that change the amino acid sequence of a protein, which are usually harmful but can occasionally be beneficial.

Nonsense Mutations

Mutations that introduce an early stop codon, typically resulting in shortened proteins and are usually harmful.

Chromosome Mutations

Changes in the structure or number of chromosomes, which may involve deletion, duplication, inversion, and translocation.

Photorepair

A specific DNA repair mechanism that repairs damage caused by UV radiation using the enzyme photolyase.

Excision Repair

A non-specific DNA repair mechanism that can correct multiple types of DNA damage.

Regulation of Gene Expression

The process by which a cell controls the amount of gene products produced, determining if a gene is active or inactive.

Operon

A cluster of genes under the control of a single promoter, allowing coordinated regulation in prokaryotes.

lac Operon

The operon involved in lactose metabolism in E. coli, containing genes that code for enzymes needed to break down lactose.

trp Operon

An operon that is normally active for tryptophan synthesis but can be repressed when tryptophan levels are high.

Eukaryotic Gene Regulation Levels

The five levels of gene regulation in eukaryotes: pre-transcriptional, transcriptional, post-transcriptional, translational, and post-translational.