How do regulatory proteins and RNA polymerase "know" which genes to transcribe at specific times?
441939
Entire courses and course of study are devoted to this question.  But here are some examples:\n\nSignal Transduction Pathways - This is a really broad category.  Cells communicate with the extracellular "milieu" using surface receptors.  When a certain signal molecule binds to the receptor, this initiates a signal cascade.  At the end of many of these cascades are transcription factors and regulatory pathways that can initiate or block transcription.  So the presence or absence of certain substances results in certain molecules that initiate transcription of certain genes.\n\nRhythms - Some proteins can interact with other proteins and regulate each others presence or absence.  This is particularly important for circadian rhythms and regulation of the cell cycle.  One protein initiates transcription of the another protein, and this other protein in turn down regulates transcription of the original protein.  The other protein eventually degrades, the the original protein's function returns.   \n\nIn essence, cells can sense what they need through proteins.  These proteins can signal other proteins which can eventually lead to the initiation or blocking of transcription. \n\nHope that helps!
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It is called Phosphorylation\n\nIn eukaryotes, protein phosphorylation is probably the most important regulatory event. Many enzymes and receptors are switched "on" or "off" by phosphorylation and dephosphorylation. Phosphorylation is catalyzed by various specific protein kinases, whereas phosphatases dephosphorylate.\n\nA protein kinase is an enzyme that modifies other proteins by chemically adding phosphate groups to them (phosphorylation). This usually results in a functional change of the target protein (substrate) by changing enzyme activity, cellular location, or association with other proteins. Up to 30% of all proteins may be modified by kinase activity, and kinases are known to regulate the majority of cellular pathways, especially those involved in signal transduction, the transmission of signals within the cell. The human genome contains about 500 protein kinase genes; they constitute about 2% of all eukaryotic genes.\n\nAdding a phosphoryl (PO3) to a polar R group of an amino acid might not seem like it would do much to a protein, but it can actually turn a nonpolar hydrophobic protein into a polar and extremely hydrophilic molecule. Phosphorylation is observed on serine, threonine, tyrosine and histidine residues.\n\nAn example of the important role that phosphorylation plays is the p53 tumor suppressor gene, which—when active—stimulates transcription of genes that suppress the cell cycle, even to the extent that it undergoes apoptosis. However, this activity should be limited to situations where the cell is damaged or physiology is disturbed. To this end, the p53 protein is extensively regulated. In fact, p53 contains more than 18 different phosphorylation sites.
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As far as using for detection, its very vulnerable to showing false positives from non-specific binding.  In addition, because of the relatively low level of mRNA, it can only be used for fairly abundant messages.  It is somewhat difficult to separate non-specific from specific binding, but of course it can be done.  In addition, it only shows the presence of message-it does not tell about the level of protein translation.
240001
when dna is copied to rna this is called translation, when rna makes the protien it it is called transcription
500125
The answer is B\n\nA. Transcription always occurs in the nucleus (in eukaryotes) because transcription uses an RNA polymerase to copy the DNA which is inside the nucleus. Translation is done in the endoplasmic reticulum by ribosomes which read the mRNA (the product of transcription) to produce proteins.\n\nB. Both Transcription and Translation require complementary pairing, thats the whole point.\n\nC. Transcription involves polymerizing nucleotides and translation polymerizes amino acids\n\nD. Translation occurs in ribosomes, transcription from above occurs in the nucleus.\n\nE. Transcription involves RNA polymerase, and translation does not :)
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Eukaryotic Regulation \n\n    A. Expression of Genes \n\n        1. A genome is all of a cell's genes that code for protein products. \n        2. Eukaryotes lack a universal regulatory mechanism to control expression of genes coding proteins. \n        3. There are four primary levels of control of gene activity. \n            a. Transcriptional control in nucleus determines which structural genes are transcribed and rate of \n                transcription; includes organization of chromatin and transcription factors initiating transcription. \n            b. Posttranscriptional control occurs in nucleus after DNA is transcribed and preliminary mRNA forms. \n                1) This may involve differential processing of preliminary mRNA before it leaves the nucleus. \n                2) Speed with which mature mRNA leaves nucleus affects ultimate amount of gene product. \n            c. Translational control occurs in cytoplasm after mRNA leaves nucleus but before protein product. \n                1) Life expectancy of mRNA molecules can vary, as well as theirability to bind ribosomes. \n                2) Some mRNA's may need additional changes before they aretranslated at all. \n            d. Posttranslational control takes place in the cytoplasm afterprotein synthesis. \n                1) Polypeptide products may undergo additional changes before they are biologically functional. \n                2) A functional enzyme is subject to feedback control; binding of an end product can change the \n                    shape of an enzyme so it no longer carries out its reaction.
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Steroids bind to proteins which then bind to specific regions of DNA utilizing zinc fingers. The protein can then regulate transcription of genes, either by promoting transcription or preventing it.\n\nLactose binds to the LacI protein, allowing the protein to bind to the promoter site on the DNA. This regulates transcription by preventing it from occurring.\n\nTherefore, steroids and lactose are similar because they bind to proteins which then bind directly to DNA to regulate transcription.\n\nHope this helps!
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Messenger RNA (mRNA) is RNA that encodes and carries information from DNA during transcription to sites of protein synthesis to undergo translation in order to yield a gene product.\n\nTransfer RNA (abbreviated tRNA) is a small RNA chain (74-93 nucleotides) that transfers a specific amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis during translation. It has sites for amino-acid attachment and codon (a particular sequence of 3 bases) recognition. The codon recognition is different for each tRNA and is determined by the anticodon region, which contains the complementary bases to the ones encountered on the mRNA.\n\nRibosomal RNA (rRNA) is the primary constituent of ribosomes. Ribosomes are the protein-manufacturing organelles of cells and exist in the cytoplasm. rRNA is transcribed from DNA, like all RNA. Ribosomal proteins are transported into the nucleus and assembled together with rRNA before being transported through the nuclear membrane. This type of RNA makes up the vast majority of RNA found in a typical cell. While proteins are also present in the ribosomes, solely rRNA is able to form peptides. Therefore ribosome often is referred to as ribozyme.
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Reaching into the bag of diminishing memory, these codons, when read by the polymerase enzyme, triggers (Starts) the enzyme to begin the process of transcribing bases into RNA, then on to amino acids and finally protiens.
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"silent information regulator" proteins.
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The answer is A, translation.\n\n\nDuring translation, the messenger RNA copies information from DNA to produce proteins. The information gets read by  ribosomes which facilitate the production of proteins.
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Store genes on chromosome\n \nOrganize genes into chromosomes to allow cell division.\n\nTransport regulatory factors & gene products via nuclear pores \n\nProduce messages ( messenger Ribonucleic acid or mRNA) that code for proteins \n\nProduce ribosomes in the nucleolus \n\nOrganize the uncoiling of DNA to replicate  key genes\n\n\n\n...and it's nucleus (777 above)
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Yes, is the answer to your question. Transcription takes place when the chromosomes are extended or unwrapped. The protiens in charge of the transcription will go to either strand to make the RNA copy and then go to the other strand later. This happens very rapidly, like copy many base pairs per second.
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I'm guessing, you are talking a gene whose expression levels are controled by other proteins, and the "local regulator" is the bit of DNA close to the gene that those other proteins bind to, to upregulate, or down regulate the gene in question.
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If a cell has a sequence of DNA that can be transcribed, that means it can be made into RNA. RNA is then translated into proteins for the cell to use. Every 3 RNA nucleotides codes for an amino acid which are used to build proteins. The proteins are built in the cell's ribosomes using messenger RNA and transfer RNA; both of which were transcribed from the original DNA sequence.\n\nSo the cell that has a sequence of DNA that can be transcribed has the ability to make protein structures for whatever it needs; enzymes or physical structure.
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> *How are the codes for proteins carried from the nucleus to the ribosomes?\nmRNA, messenger RNA, is transcribed from the "template" strand of DNA for that particular gene.  The mRNA may leave the nucleus and enter the cytoplasm, where it will encounter a ribosome.\n\n> A single strand of DNA has the bases AGTAAC. Using letters, show a matching DNA strand from this pattern.\nTCATTG\n\n> *How is tRNA used when cells build proteins?\ntRNA is a sequence of three nucelotides bound to the corresponding amino acid.  The ribosomes "read" the mRNA, match it, in reading frame, with the corresponding tRNA, and add the amino acid to the growing polypeptide.\n\n> *You begin as one cell. Compare the DNA in one of your brain cells to the DNA in one of your heart cells\nGenerally speaking, the nuclear DNA in your heart cell will be the same as the nuclear DNA in your brain cell.
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The statement is true. If you assume that takeing dna to rna is the same language, then that would be transcribing, while rna to prtien is a different language, that is translating