Fluorescence in situ hybridization (FISH) is a method used to detect specific DNA sequences in chromosomes. The technique uses fluorescent probes that bind to only those parts of the chromosome with a high degree of sequence similarity to the probe. This makes it possible to visualize individual chromosomes and specific regions within chromosomes. FISH can […]
Somatic cell hybridization is a method used to create recombinant DNA molecules. The technique involves combining DNA from two different sources, usually from different species. The resulting DNA molecule will contain genetic information from both parents. Somatic cell hybridization can be used to create transgenic animals or plants, which are organisms that contain foreign DNA. […]
What is an Antibody? The term antibody is used to describe a protein that is produced by the immune system in response to the presence of a foreign substance, known as an antigen. Antigens can be found on the surface of bacteria, viruses, and other pathogens. They can also be found on the surface of […]
What is a Chromosome? A chromosome is a long, continuous strand of DNA that contains many genes. Genes function as the basic unit of heredity in living cells, coding for various proteins. Each gene is located at a specific position on the chromosome, known as its locus. Chromosomes also contain non-coding regions of DNA, which […]
Unlike prokaryotes, eukaryotes must process mRNAs before they can be translated into proteins. The primary mRNA transcript is first made by transcription of the DNA by RNA pol II. The transcript contains both introns and exons, hence it is called heterogenous RNA (hRNA). The 5′ end of the hRNA is capped and a polyA tail […]
In prokaryotic cells the focus of the regulation of gene expression is almost entirely at the level of the initiation of transcription. However, in eukaryotic cells, regulation of gene expression can occur at all stages of transcription and translation, and even at protein stability. Opportunities for Gene Regulation in Gene Expression in Eukaryotes Those common […]
Anti-Termination It is possible for prokaryotic RNA polymerase to ignore termination signals and continue to transcribe until a downstream termination signal is reached. This mechanism is used by lambda phage. The lambda N gene codes for pN which interacts with polymerase RNA to enable it to read through to genes further downstream. Another antiterminator called […]
Gene Regulation at Transcriptional Termination In the previous article we saw how RNA polymerase determines how to start transcription. In this article, we will examine how it decides to end transcription. Before we dive in, however, let’s take some time to remind ourselves of the lay of the land. So far, we are well familiar […]
Prokaryotes are able to regulate gene expression by applying unique tricks in their toolbox. In prokaryotic cells, genes expression is regulated almost entirely at the level of the initiation of transcription. In eukaryotic cells, regulation of gene expression can occur at all stages of transcription and translation, and even after a protein is made. I […]
