Riboswitch
A riboswitch is a structured RNA element that can bind a small molecule and change gene expression without needing a separate regulatory protein.
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Trp operon
The trp operon is a bacterial gene-control system that reduces tryptophan-making enzymes when tryptophan is already plentiful.
Lac operon
The lac operon is a classic bacterial gene-control circuit that turns lactose-use genes on when lactose is available and preferred glucose fuel is scarce.
Operon
An operon is a cluster of genes controlled together by shared regulatory DNA, usually in bacteria and archaea. Operons let cells transcribe related genes as one unit and adjust gene expression in response to nutrients or other conditions.
Transcription factor
A transcription factor is a protein that helps regulate gene transcription. Many transcription factors bind specific DNA sequences at promoters, enhancers, or other regulatory elements and influence whether RNA polymerase starts or changes transcription.
Enhancer
An enhancer is a regulatory DNA element that can increase transcription of a target gene. Enhancers bind transcription factors and can act over long genomic distances, often through chromatin looping that brings them near promoters.
Promoter
A promoter is a DNA region that helps start transcription of a gene. It provides binding sites for RNA polymerase and regulatory proteins, helping cells decide where and when RNA synthesis begins.
CpG island
A CpG island is a stretch of DNA with a high frequency of cytosine-guanine CpG sites, often near gene promoters. CpG islands are important in genome annotation, transcription regulation, and DNA methylation studies.
DNA methylation
DNA methylation is an epigenetic modification in which methyl groups are added to DNA bases. In many eukaryotes, methylation at CpG sites helps regulate gene activity, genome stability, development, and cell identity.
Histone
Histones are DNA-packaging proteins that help organize eukaryotic genomes into chromatin. They form the core of nucleosomes, influence access to genes, and carry chemical modifications involved in epigenetic regulation.
Nucleosome
A nucleosome is the basic repeating unit of chromatin in eukaryotic cells. It packages DNA by wrapping it around histone proteins, helping long genomes fit inside nuclei while shaping access to genes.
Chromatin
Chromatin is the DNA-protein material that packages eukaryotic genomes inside the cell nucleus. Its structure helps compact DNA while also controlling access for transcription, replication, repair, and chromosome formation.
Epigenetics
Epigenetics studies changes in gene activity that do not alter the underlying DNA sequence. It helps explain how cells with the same genome can behave differently, respond to environments, and maintain specialized identities.
RNA sequencing
RNA sequencing, often called RNA-seq, measures RNA molecules in a sample using sequencing. It helps researchers study gene expression, transcriptomes, cell states, disease biology, and how genomes are used in living cells.
DNA sequencing
DNA sequencing is the process of determining the order of nucleotide bases in DNA. It turns genetic material into readable data, making modern genomics, disease research, evolutionary studies, and metagenomics possible.
Metagenomics
Metagenomics studies genetic material recovered directly from mixed samples such as soil, seawater, or the human gut. Instead of growing one organism at a time, it uses sequencing and computation to examine whole microbial communities.
Bacteriophage
A bacteriophage is a virus that infects bacteria. Phages shape microbial ecosystems, move genes between bacterial cells, and are studied as tools for genetics, biotechnology, and possible treatment of some bacterial infections.
Horizontal gene transfer
Horizontal gene transfer is the movement of genetic material between organisms outside ordinary parent-to-offspring inheritance. It is especially important in bacteria, where transformation, transduction, and conjugation can spread new traits through populations.
Bacterial transformation
Bacterial transformation is the uptake of external DNA by a bacterial cell. In nature, it is one route of horizontal gene transfer; in laboratories, it is a standard way to introduce plasmids or recombinant DNA into competent bacteria for cloning, expression, and analysis.
DNA ligase
DNA ligase is an enzyme that joins breaks in the sugar-phosphate backbone of DNA. It seals nicks during DNA replication and repair, and purified ligases are essential tools for joining DNA fragments in cloning and recombinant DNA work.
Recombinant DNA
Recombinant DNA is DNA assembled from sequences that did not originally occur together. In the lab, researchers can join DNA fragments with vectors such as plasmids, introduce them into host cells, and use the resulting molecules to study genes, make proteins, and build biotechnology tools.
Plasmid
A plasmid is a small DNA molecule, often circular and found in bacteria, that can replicate separately from the main chromosome. Natural plasmids can carry useful genes such as antibiotic resistance genes, and engineered plasmids are central tools in cloning, gene expression, and biotechnology.
Restriction enzyme
A restriction enzyme is a DNA-cutting enzyme, usually isolated from bacteria, that recognizes specific DNA sequences and cuts at or near those sites. Restriction enzymes are natural defense tools and practical workhorses for DNA cloning, mapping, fragment analysis, and biotechnology.
Gel electrophoresis
Gel electrophoresis is a laboratory method for separating DNA, RNA, or proteins as they move through a gel under an electric field. It is widely used to check PCR products, estimate fragment size, compare samples, and prepare biomolecules for further analysis.