https://www.khanacademy.org/science/ap-biology/gene-expression-and-regulation/regulation-of-gene-expression-and-cell-specialization/a/the-lac-operon
The lac operon of E. coli contains genes involved in lactose metabolism. It's expressed only when lactose is present and glucose is absent. Two regulators turn the operon "on" and "off" in response to lactose and glucose levels: the lac repressor and catabolite activator protein (CAP). The lac repressor acts as a lactose sensor.

https://en.wikipedia.org/wiki/Lac_operon
The lactose operon (lac operon) is an operon required for the transport and metabolism of lactose in E. coli and many other enteric bacteria.Although glucose is the preferred carbon source for most enteric bacteria, the lac operon allows for the effective digestion of lactose when glucose is not available through the activity of β-galactosidase. Gene regulation of the lac operon was the first

https://bio.libretexts.org/Bookshelves/Genetics/Online_Open_Genetics_(Nickle_and_Barrette-Ng)/12%3A_Regulation_of_Gene_Expression/12.01%3A_The_lac_Operon
CAP is an allosteric activator of the lac operon. A second aspect of lac operon regulation is conferred by a trans-factor called cAMP binding protein (CAP, Figure \(\PageIndex{4}\)).CAP is another example of an allosterically regulated trans-factor.Only when the CAP protein is bound to cAMP can another part of the protein bind to a specific cis-element within the lac promoter called the CAP

https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/General_Biology_(Boundless)/16%3A_Gene_Expression/16.05%3A_Prokaryotic_Gene_Regulation_-_The_lac_Operon-_An_Inducer_Operon
A major type of gene regulation that occurs in prokaryotic cells utilizes and occurs through inducible operons. Inducible operons have proteins that can bind to either activate or repress transcription depending on the local environment and the needs of the cell. The lac operon is a typical inducible operon.

https://www.khanacademy.org/science/ap-biology/gene-expression-and-regulation/regulation-of-gene-expression-and-cell-specialization/v/lac-operon
Lac operon. The lac operon in E. coli regulates lactose metabolism. It consists of three genes (lacZ, lacY, and lacA) and is controlled by a promoter, operator, and CAP site. Lactose presence triggers allolactose production, which inhibits the lac repressor, allowing transcription. Glucose levels impact transcription through cyclic AMP and the

https://bio.libretexts.org/Courses/University_of_California_Davis/BIS_2A%3A_Introductory_Biology_(Britt)/02%3A_Face-2-Face/2.10%3A_Regulation_of_Gene_Expression
Putting it all together: Inducing expression of the lac operon. For the lac operon to be activated, two conditions must be met. First, the level of glucose must be very low or non-existent. Second, lactose must be present. Only when glucose is absent and lactose is present will the lac operon be transcribed.

https://microbeonline.com/lac-operon-mechanism/
The lac operon is a well-known example of an inducible gene network that regulates the transport and metabolism of lactose in Escherichia coli. It encodes the genes for the internalization of extracellular lactose and then its conversion to glucose. The lactose operon of E. coli is turned ON only when lactose is available (and glucose, the

https://microbenotes.com/lac-operon/
Positive control or regulation of gene expression is when the regulatory protein binds to DNA and increases the rate of transcription. In this case, the regulatory protein is called an activator. The CAP/CRP involved in regulating the lac operon is a good example of an activator. Thus the lac operon is subject to both negative and positive control.

https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/lac-operon
The lac operon of E. coli is the hypothesis for gene regulation; the key component is the lacI repressor. The uncontrolled-type DNA sequence of lac operon has three lac repressor recognition sites in a stretch of 500 base pairs. It also has a binding site for catabolite activator proteins (CAP), which is considered to be an activator.

https://ocw.mit.edu/courses/7-01sc-fundamentals-of-biology-fall-2011/pages/molecular-biology/gene-regulation-and-the-lac-operon/
This session will briefly outline some general principles of gene regulation. In addition, a specific example of gene regulation in bacteria will be presented in detail. Learning Objectives. To recall and understand the different mechanisms working together to regulate the Lac operon. To distinguish positive and negative regulatory mechanisms.

https://openstax.org/books/microbiology/pages/11-7-gene-regulation-operon-theory
The lac Operon: An Inducible Operon. The lac operon is an example of an inducible operon that is also subject to activation in the absence of glucose (Figure 11.34). The lac operon encodes three structural genes necessary to acquire and process the disaccharide lactose from the environment, breaking it down into the simple sugars glucose and

https://ocw.mit.edu/courses/7-01sc-fundamentals-of-biology-fall-2011/resources/the-lac-operon/
Alternative Approaches to Molecular Biology. Gene Regulation and the Lac Operon. Exam 2. Genetics. Mendel's Laws. Linkage and Recombination, Genetic Maps. Pedigrees. Biochemical Genetics. Exam 3.

https://www.nature.com/scitable/topicpage/positive-transcription-control-the-glucose-effect-1009/
The lac operon is therefore positively regulated by the absence of glucose catabolites (Figure 1). Figure 1: The lac operon is activated when intracellular glucose levels are low.

https://www.sciencefacts.net/lac-operon.html
The lac operon consists of the following components: 1. Structural Genes: The three structural genes in a lac operon are:. lacZ: It encodes β-galactosidase, an enzyme that breaks down lactose into glucose and galactose.; lacY: It encodes lactose permease, a protein that transports lactose into the cell.; lacA: It encodes transacetylase, an enzyme involved in lactose metabolism.

https://bio.libretexts.org/Under_Construction/Cell_and_Molecular_Biology_(Bergtrom)/12%3A_Regulation_of_Transcription_and_Epigenetic_Inheritance/12.02%3A_Gene_Regulation_in_Prokaryotes-_the_Lactose_(lac)_Operon
12.2.2. Negative Regulation of the lac Operon by Lactose. Repression of lac-operon activity involves a repressor protein that must be removed for gene expression to occur.The repressor protein product of the I gene is always made and present in E. coli cells; expression of the I gene is constitutive, meaning it is unregulated.In the absence of lactose in the growth medium, the repressor

https://www.khanacademy.org/science/ap-biology/gene-expression-and-regulation/regulation-of-gene-expression-and-cell-specialization/a/overview-gene-regulation-in-bacteria
For instance, a well-studied operon called the lac operon contains genes that encode proteins involved in uptake and metabolism of a particular sugar, lactose. Operons allow the cell to efficiently express sets of genes whose products are needed at the same time.

https://byjus.com/biology/lac-operon-regulation-gene-expression/
The lac operon consists of: Regulatory gene i - It codes for the repressor protein. z gene - It codes for beta-galactosidase which catalyzes the hydrolysis of lactose into glucose and galactose. y gene - It codes for permease which regulates the lactose permeability in the cell. a gene - It codes for transacetylase which assists the

https://biologydictionary.net/lac-operon/
The lac operon, short for lactose operon, is a series of three genes in bacteria that produce the necessary enzymes to obtain energy from lactose. An operon is any series of genes that are controlled by the same promoter and operator sequences, which tell the enzymes responsible for transcribing mRNA where to attach to the DNA.

https://www.news-medical.net/life-sciences/The-Lac-Operon-in-E-Coli.aspx
The lac operon system of E. coli has been utilized widely for both experimental and industrial purposes. The lacZ gene, which encodes β-galactosidase, is used most extensively as a reporter gene

https://biologyreader.com/lac-operon.html
Lac-operon is a system that involves the regulation of protein synthesis or the synthesis of enzymes by a set of genes. This concept can be well studied by the gene expression in prokaryotes like E.coli and other bacteria. The concept of Lac-operon was first explained by Jacob and Monad in E.coli.. Lac-operon refers to the system that can regulate the metabolism or utilization of lactose (as

https://bio.libretexts.org/Bookshelves/Biochemistry/Supplemental_Modules_(Biochemistry)/2%3A_Bacteria/2.6%3A_The_lac_Operon_CAP_site_DNA_footprinting
Figure 2.6.1: lac Operon. lac Z codes for b -galactosidase, which is an enzyme that cleaves b -galactosides (e.g. lactose). lac Y codes for permease, which is involved in the transport of b -galactosides into the cell. lac A codes for b -galactoside transacetylase, which acetylates b -galactosides. A mutation in either lac Z or lac Y can lead

https://golifescience.com/lac-operon-gene-expression-in-prokaryotes/
The Lac operon (Lactose Operon) mechanism does permit sensitive responses to a rapidly changing environment. However, ensuring adjustments are for the short term, briefly affecting cell division and growth without producing permanent alterations in Prokaryotic gene expression. This is in keeping with the short life cycles of these organisms.

https://phet.colorado.edu/en/simulation/gene-machine-lac-operon
The lac operon is a set of genes which are responsible for the metabolism of lactose in some bacterial cells. Explore the effects of mutations within the lac operon by adding or removing genes from the DNA. Build a gene network! The lac operon is a set of genes which are responsible for the metabolism of lactose in some bacterial cells.