Search Results for:
Gene Regulation in Prokaryotes
Learning Outcomes Understand the basic steps in gene regulation in prokaryotic cells In bacteria and archaea, structural proteins with related functions—such as the genes that encode the enzymes that catalyze the many steps in a single biochemical pathway—are usually encoded together within the genome in a block called an operon and are transcribed together under Read more »
Prokaryotic Transcription
Learning Outcomes Understand the basic steps in the transcription of DNA into RNA in prokaryotic cells Prokaryotes do not have membrane-enclosed nuclei. Therefore, the processes of transcription, translation, and mRNA degradation can all occur simultaneously. The intracellular level of a bacterial protein can quickly be amplified by multiple transcription and translation events occurring concurrently on Read more »
Introduction to Prokaryotic Transcription and Translation
Outline the process of prokaryotic transcription and translation The prokaryotes, which include bacteria and archaea, are mostly single-celled organisms that, by definition, lack membrane-bound nuclei and other organelles. A bacterial chromosome is a covalently closed circle that, unlike eukaryotic chromosomes, is not organized around histone proteins. The central region of the cell in which prokaryotic Read more »
Cytoplasm
Learning Outcomes Describe the basic composition of cytoplasm Before we begin looking at individual organelles, we do need to briefly address the matrix in which they sit: the cytoplasm. The part of the cell referred to as cytoplasm is slightly different in eukaryotes and prokaryotes. In eukaryotic cells, which have a nucleus, the cytoplasm is Read more »
Post-Transcriptional Control of Gene Expression
Learning Outcomes Understand RNA splicing and explain its role in regulating gene expression Describe the importance of RNA stability in gene regulation RNA is transcribed, but must be processed into a mature form before translation can begin. This processing after an RNA molecule has been transcribed, but before it is translated into a protein, is Read more »
Eukaryotic Transcription Gene Regulation
Learning Outcomes Discuss the role of transcription factors in gene regulation Like prokaryotic cells, the transcription of genes in eukaryotes requires the action of an RNA polymerase to bind to a DNA sequence upstream of a gene in order to initiate transcription. However, unlike prokaryotic cells, the eukaryotic RNA polymerase requires other proteins, or transcription Read more »
Eukaryotic Epigenetic Gene Regulation
Learning Outcomes Explain the process of epigenetic regulation The human genome encodes over 20,000 genes; each of the 23 pairs of human chromosomes encodes thousands of genes. The DNA in the nucleus is precisely wound, folded, and compacted into chromosomes so that it will fit into the nucleus. It is also organized so that specific Read more »
Prokaryotic and Eukaryotic Gene Regulation
Learning Outcomes Compare prokaryotic and eukaryotic gene regulation To understand how gene expression is regulated, we must first understand how a gene codes for a functional protein in a cell. The process occurs in both prokaryotic and eukaryotic cells, just in slightly different manners. Prokaryotic organisms are single-celled organisms that lack a cell nucleus, and Read more »
Expression of Genes
Learning Outcomes Discuss why every cell does not express all of its genes For a cell to function properly, necessary proteins must be synthesized at the proper time. All cells control or regulate the synthesis of proteins from information encoded in their DNA. The process of turning on a gene to produce RNA and protein Read more »
Repressors
Learning Outcomes Explain the roles of repressors in negative gene regulation Tryptophan Operon: A Repressor Operon Bacteria such as E. coli need amino acids to survive. Tryptophan is one such amino acid that E. coli can ingest from the environment. E. coli can also synthesize tryptophan using enzymes that are encoded by five genes. These Read more »
