https://www.khanacademy.org/science/ap-biology/gene-expression-and-regulation/regulation-of-gene-expression-and-cell-specialization/v/dna-and-chromatin-regulation 2023-05-16T18:15:14.661422403Z DNA and chromatin regulation Gene regulation controls when and how much a gene is expressed. Chromatin regulation and DNA methylation are two ways to regulate genes. Chromatin regulation involves histone modifications, while DNA methylation adds methyl groups. Both are examples of epigenetic regulation and are crucial for proper cell function. Tracy Kim Kovach video https://cdn.kastatic.org/googleusercontent/rKt75zqJJWt-iSZjO3ex3IoTFp6H9cBWJtGk6u_p6H3RMsM7Y0MyKYo9IQOKhj1Kwvn8rq76Jef1f1dzHT-A9iUeWg DNA and chromatin regulation Gene regulation controls when and how much a gene is expressed. Chromatin regulation and DNA methylation are two ways to regulate genes. Chromatin regulation involves histone modifications, while DNA methylation adds methyl groups. Both are examples of epigenetic regulation and are crucial for proper cell function. https://cdn.kastatic.org/ka-youtube-converted/OqRt723t33o.mp4/OqRt723t33o.mp4 321 Regulation of gene expression https://www.khanacademy.org/science/hs-bio/x230b3ff252126bb6:gene-expression-and-regulation/x230b3ff252126bb6:untitled-348/v/gene-expression-and-regulation 2022-09-24T04:45:13.131282509Z Gene expression and regulation Each chromosome consists of a single very long DNA molecule, and each gene on the chromosome is a particular segment of that DNA. The instructions for forming species’ characteristics are carried in DNA. All cells in an organism have the same genetic content, but the genes used (expressed) by the cell may be regulated in different ways. Not all DNA codes for a protein; some segments of DNA are involved in regulatory or structural functions, and some have no as-yet known function. Sal Khan video https://cdn.kastatic.org/ka_thumbnails_cache/74b22213-7394-4455-9605-63fd962929bd_1280_720_base.png Gene expression and regulation Each chromosome consists of a single very long DNA molecule, and each gene on the chromosome is a particular segment of that DNA. The instructions for forming species’ characteristics are carried in DNA. All cells in an organism have the same genetic content, but the genes used (expressed) by the cell may be regulated in different ways. Not all DNA codes for a protein; some segments of DNA are involved in regulatory or structural functions, and some have no as-yet known function. https://cdn.kastatic.org/ka-youtube-converted/fdzsrTpUe4w.mp4/fdzsrTpUe4w.mp4 432 Regulation of gene expression https://www.khanacademy.org/science/ap-biology/gene-expression-and-regulation/regulation-of-gene-expression-and-cell-specialization/v/lac-operon 2023-06-22T09:32:02.370557018Z 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 catabolite activator protein. Sal Khan video https://cdn.kastatic.org/ka_thumbnails_cache/636235f8-42bd-4ecf-b2f9-31e8afc08d5e_1280_720_base.png 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 catabolite activator protein. https://cdn.kastatic.org/ka-youtube-converted/LuOaEe89_HE.mp4/LuOaEe89_HE.mp4 665 Regulation of gene expression https://www.khanacademy.org/science/ap-biology/gene-expression-and-regulation/regulation-of-gene-expression-and-cell-specialization/v/trp-operon 2023-08-07T17:09:37.131449861Z Trp operon The Trp operon plays a crucial role in tryptophan production, an essential amino acid. In E. Coli, the operon consists of genes and regulatory DNA sequences, including the promoter and operator. Tryptophan acts as a co-repressor, binding to the Trp repressor and inhibiting transcription when abundant. Additionally, feedback inhibition occurs, where tryptophan directly inhibits enzyme activity. This regulation ensures efficient resource use and tryptophan biosynthesis. Sal Khan video https://cdn.kastatic.org/googleusercontent/cKDhNPbg9NwEQ7BrZohPiRZrtMBng84NsP5NfM08vY5NVmWEzHj4gR9l1fJMg-PLkEosYyOEaDab_R1THXsKD_yj Trp operon The Trp operon plays a crucial role in tryptophan production, an essential amino acid. In E. Coli, the operon consists of genes and regulatory DNA sequences, including the promoter and operator. Tryptophan acts as a co-repressor, binding to the Trp repressor and inhibiting transcription when abundant. Additionally, feedback inhibition occurs, where tryptophan directly inhibits enzyme activity. This regulation ensures efficient resource use and tryptophan biosynthesis. https://cdn.kastatic.org/ka-youtube-converted/EvLy_1_Y3tk.mp4/EvLy_1_Y3tk.mp4 396 Regulation of gene expression https://www.khanacademy.org/science/ap-biology/gene-expression-and-regulation/regulation-of-gene-expression-and-cell-specialization/a/overview-gene-regulation-in-bacteria 2021-04-29T07:51:29Z Overview: Gene regulation in bacteria Overview of operons, regulatory DNA sequences, & regulatory genes. Repressor & activator proteins. article https://www.khanacademy.org/science/ap-biology/gene-expression-and-regulation/regulation-of-gene-expression-and-cell-specialization/a/the-lac-operon 2021-04-29T07:53:47Z The lac operon Regulation of genes for lactose utilization. lac repressor, catabolite activator protein, and cAMP. article https://www.khanacademy.org/science/ap-biology/gene-expression-and-regulation/regulation-of-gene-expression-and-cell-specialization/v/regulation-of-transcription 2023-06-22T15:57:36.106541556Z Regulation of transcription Gene regulation controls cell functions by determining which genes are transcribed. This process involves transcription factors, activators, enhancers, repressors, and silencers. Prokaryotes rely on gene regulation for environmental adaptation, while eukaryotes have more complex interactions and a nuclear envelope for added control. Understanding gene expression is crucial for studying cellular processes and responses. Tracy Kim Kovach video https://cdn.kastatic.org/googleusercontent/f3CU1AVUdwrg_9oHES4LZXev-LNEG8bb84JUIAAgeYFEwRJzIMdgj2rhcZ5xlqU4vz3sJHECOu3o8-srvpXonXQ Regulation of transcription Gene regulation controls cell functions by determining which genes are transcribed. This process involves transcription factors, activators, enhancers, repressors, and silencers. Prokaryotes rely on gene regulation for environmental adaptation, while eukaryotes have more complex interactions and a nuclear envelope for added control. Understanding gene expression is crucial for studying cellular processes and responses. https://cdn.kastatic.org/ka-youtube-converted/ypH-hDKpCY0.mp4/ypH-hDKpCY0.mp4 407 Regulation of gene expression https://www.khanacademy.org/science/ap-biology/gene-expression-and-regulation/regulation-of-gene-expression-and-cell-specialization/a/overview-of-eukaryotic-gene-regulation 2021-04-29T07:54:00Z Overview: Eukaryotic gene regulation How different genes are expressed in different cell types. The big picture of eukaryotic gene regulation. article