CpG islands (or CG islands) are regions with a high frequency of CpG sites.

CpG Islands

Promoter sequences are DNA sequences that define where transcription of a gene by RNA polymerase begins. Transcription factor activators can also interact with this sequence to activate transcription. Promoter sequences are typically located directly upstream of the genes they regulate. 

University of Wisconsin - Madison

Trinity College (CT)

University of Minnesota - Twin Cities

Gene expression must be regulated in order to express the genes that are needed at the right times so that cellular energy is not wasted. There are many regulatory genes required for gene regulation in eukaryotes and prokaryotes.

Gene Regulation

Transcription is the process of transcribing the genetic information of DNA into RNA transcripts. This transcript is mobile and is a copy of DNA with RNA nucleotides. This process is largely conserved in prokaryotes and eukaryotes with some significant differences between them.

Transcription

https://openstax.org/details/books/microbiology/

Microbiology covers the scope and sequence requirements for a single-semester microbiology course for non-majors. The book presents the core concepts of microbiology with a focus on applications for careers in allied health. The pedagogical features of the text make the material interesting and accessible while maintaining the career-application focus and scientific rigor inherent in the subject matter. Microbiology’s art program enhances students’ understanding of concepts through clear and effective illustrations, diagrams, and photographs.

Microbiology is produced through a collaborative publishing agreement between OpenStax and the American Society for Microbiology Press. The book aligns with the curriculum guidelines of the American Society for Microbiology.

OpenStax Microbiology Textbook

Operons are a section of genes that are all transcribed together. The operon is regulated by the promoter and operator sequence upstream of the genes in the operon. Operons are found primarily in prokaryotes.

Operon

Transcription factors are proteins that regulate genes by binding to DNA. They typically bind upstream of an operon to regulate its expression. They can be repressors and prevent RNA Polymerase from transcribing genes or activators and facilitate the binding of RNA Polymerase to transcribe genes. They respond to stimuli in the cell's environment to regulate genes.

Transcription Factors

Promoter

An operator is the DNA sequence that is usually downstream of the RNA Polymerase binding site but upstream of the first gene in the operon. The operon interacts with a transcriptional repressor. By binding to the operator sequence, repressors physically block the RNA Polymerase from interacting with the -10 and -35 sequences to transcribe.

Operator Sequence

The steps of RNA transcription are shared between eukaryotes and prokaryotes. The steps of RNA Transcription are:

1. Initiation
2. Elongation
3. Termination

The Steps of RNA Transcription

RNA Polymerase transcribes RNA transcripts from DNA templates in transcription. There are several types in eukaryotes, while prokaryotes use one type of RNA Polymerase.

RNA Polymerase

While RNA Transcription is different in key ways between prokaryotes and eukaryotes, the end products are nucleic acids. These are: 
- mRNA
- tRNA
- rRNA

End Products of RNA Transcription

  While RNA Transcription shares many of the same enzymes and components with other organisms, here we designate that differences in RNA transcription in the domains of life. 

- Prokaryotic RNA Transcription
- Eukaryotic RNA Transcription

Learn Before

Related

Learn After