Microbiology: What is actually happening of the "Lac Operon"? help, i want to compare my answer to yours.
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Control of Gene Expression: The lac operon consists of one regulatory gene (the i gene) and three structural genes (z, y, and a). The i gene codes for the repressor of the lac operon. The z gene codes for b-galactosidase (b-gal), which is primarily responsible for the hydrolysis of the disaccharide, lactose into its monomeric units, galactose and glucose. The y gene codes for permease, which increases permeability of the cell to b-galactosides. The a gene encodes a transacetylase. During normal growth on a glucose-based medium, the lac repressor is bound to the operator region of the lac operon, preventing transcription. However, in the presence of an inducer of the lac operon, the repressor protein binds the inducer and is rendered incapable of interacting with the operator region of the operon. RNA polymerase is thus able to bind at the promoter region, and transcription of the operon ensues. The lac operon is repressed, even in the presence of lactose, if glucose is also present. This repression is maintained until the glucose supply is exhausted. The repression of the lac operon under these conditions is termed catabolite repression and is a result of the low levels of cAMP that result from an adequate glucose supply. The repression of the lac operon is relieved in the presence of glucose if excess cAMP is added. As the level of glucose in the medium falls, the level of cAMP increases. Simultaneously there is an increase in inducer binding to the lac repressor. The net result is an increase in transcription from the operon. The ability of cAMP to activate expression from the lac operon results from an interaction of cAMP with a protein termed CRP (for cAMP receptor protein). The protein is also called CAP (for catabolite activator protein). The cAMP-CRP complex binds to a region of the lac operon just upstream of the region bound by RNA polymerase and that somewhat overlaps that of the repressor binding site of the operator region. The binding of the cAMP-CRP complex to the lac operon stimulates RNA polymerase activity 20-to-50-fold.
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http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20101/Bio%20101%20Lectures/DNA/dna.htm
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What class was this in? What grade level? What text were you using?  I may be able to help you if I know the context in which the question was raised. I have a feeling that I am not getting all the information you had. Please tell me and maybe I can help. I am an old chemist and microbiologist.
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For your information Julie, I had already did my homework, I was wondering if anybody else knew what Methanothermus fervidus was. And my GPA is a 4.0 so you don't have to tell me that by reading more I will accomplish more. So now you let us know when you have a more complicated question about something other than a Ham & Cheese webstite. Thank you for your time in answering my question.
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Are you looking for all known orthologues of the individual genes in the operon (I assume) or for all occurences of these particular genes in an operon in other organisms (bacteria)?\n\n\n\n/////////\nI would try to look at "HomoloGENE", "Genome" and "UniGene" at the Entrez gateway at the US National Library of Medicine, Nat'l Ctr. for Biotechnology Info. (NCBI) \n\nhttp://www.ncbi.nlm.nih.gov/gquery/gquery.fcgi?itool=toolbar
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Hi friend,\nSince your question is a bit technical, i assume that you are from a microbiology/biochemistry background. Hence the answer too is given with technical details. If you can't digest it, i may be able to give a simpler explanation. Just leave a comment alongside the answer.\nIt is also assumed that ur querry is about rRNA differences between EUBACTERIA and Archaea.\n\nGenerally speaking, unlike Bacterial RNA, archaean  RNAs are not capable of catalysis in the absence of other enzyme components. The structural basis of this deficiency must be in the  differences in  bacterial and archaeal sequences or higher order structure. \n    Secondary structure in Archean RNA contains all but one helix present in that of Bacterial structure, the 2 bp helix P11. This structure is adjacent to a large region in which the structure remains unknown even in bacterial RNase P RNAs. \n\n           In Eubacteria, rRNA modification is achieved exclusively by site-specific enzymes while in archaea and eukaryotes the formation of 2-O-methylriboses and pseudouridines is guided by numerous snoRNA that direct a catalytic machinery to the target sites on the pre-rRNA.        \n         \nMore over the GC content of the paired stem regions of the 16S rRNA genes in Archaea is very high and it correlates somewhat with the high  temperatureconditions they grow (or evolved in)\n\nThat's what i know of the differences. Hope thats clear,\nBye..
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lol, last minute lab write ups. afaik enzymes dont change colour, as they are not supposed to change so id bet there is something else that the enzyme works on. better put up the other reagents to get a better answer
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The mutation would abolish the repressing ability of LacI and promoters controlled by it would be transcriptionally active in the absence of lactose. It could destroy or not do anything at all to the cell.
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I'm not sure I understand the question, but I'll try anyway.  :)  If you are trying to determine IF you have both Pseudomonas and Klebsiella on in your culture, you can streak a MacConkey agar plate with the culture.  Pseudomonas cannot ferment lactose, so it will grow on the plate but remain colorless.  On the other hand, Klesiella can ferment lactose, so it will also grow on the plate but turn bright pink.  That's probably the easiest way to distinguish the two from a mixed culture.\n\nAs for the "local disinfectant" part of the question...are you trying to pull out these bacteria and then do disinfectant susceptibility testing on them?  If so, you can streak out the plate as mentioned above, then subculture each so you can get a pure culture.  Then, you do disinfectant tests on the bacteria separately by the disk diffusion method, etc.\n\nI hope that helps some!
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Bacteria are procaryotes. Their cell structure is different from those of plants and animals (Eucaryotes) they are in their own category altogether. Years and years ago they were categorized as plants. Some of them have clorophyll. How old is your brother's science book?
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Hi there, \n\nMany types of bacteria undergo cell division by a procedure called 'Binary Fission'\nYeast does not undergo cell division, however, it reproduces through 'Budding'\n\nHope this helps. If not, I'd be glad to assist you further. Bye!!\n\nrule wid style n luv@vinny
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In addition to what Jen said, I would also like to point out that although isoenzymes by definition catalyze the same reaction, they often do it with different kinetic parameters.\n\nFor example, there may be different reaction order, affinities (K-constants), and the like, between two isozenzymes, even though they both perform the same product-to-substrate conversion.
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Mm...I remember when I did this lab last year. I will try to help you \n\n1. I don't remember. If you add more details...I'll be able to help you\n2. We need an equilibration period, so we start the experiment in all the vials at the same condition. SO..all of them are at the same temperature, pressure and we won't get far away from the expected results.\n\n3. the volume? Well...I am not sure about this one. You should explain a little bit more. But..I remember that KOH that you  you put in the cotton will absorbe CO2 produced by the vials that have the respiration process going on.\n\n4. again..provide background information about the experiment\n\nPLEASE...we know that it is about cellular respiration. But it the questions don't make sense to us if we don't know a little more about the procedure!
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If we're talking about bacteria, this sounds like the lac operon.  The absence of lactose causes a repressor protein to halt production of beta-galactosidase.  When lactose is present, the machinery to produce beta-galactosidase is released from repression.  This makes sense, since the presence of lactose dictates the need for catabolic enzymes to metabolize the lactose.\n\nSearch for information on the lac operon for plenty of information, it's a very well-elucidated mechanism.
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How is Recombinant DNA made? \nThere are three different methods by which Recombinant DNA is made. They are \nTransformation, Phage Introduction, and Non-Bacterial Transformation. Each \nare described separately below. \n\nTransformation\nThe first step in transformation is to select a piece of DNA to be inserted \ninto a vector. The second step is to cut that piece of DNA with a restriction \nenzyme and then ligate the DNA insert into the vector with DNA Ligase. The insert contains a selectable \nmarker which allows for identification of recombinant molecules. An antibiotic \nmarker is often used so a host cell without a vector dies when exposed to a certain \nantibiotic, and the host with the vector will live because it is resistant. \n\nThe vector is inserted into a host cell, in a process called transformation. One \nexample of a possible host cell is E. Coli. The host cells must be specially \nprepared to take up the foreign DNA. \n\nSelectable markers can be for antibiotic resistance, color changes, or any other \ncharacteristic which can distinguish transformed hosts from untransformed hosts. \nDifferent vectors have different properties to make them suitable to different \napplications. Some properties can include symmetrical cloning sites, size, and \nhigh copy number. \n\nNon-Bacterial Transformation\nThis is a process very similar to Transformation, which was described above. The \nonly difference between the two is non-bacterial does not use bacteria such as E. Coli \nfor the host. \n\nIn microinjection, the DNA is injected directly into the nucleus of the cell being \ntransformed. In biolistics, the host cells are bombarded with high velocity \nmicroprojectiles, such as particles of gold or tungsten that have been coated \nwith DNA. \n\nPhage Introduction\nPhage introduction is the process of transfection, which is equivalent to transformation, \nexcept a phage is used instead of bacteria. In vitro packagings of a vector is used. \nThis uses lambda or MI3 phages to produce phage plaques which contain recombinants. \nThe recombinants that are created can be identified by differences in the \nrecombinants and non-recombinants using various selection methods.
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Find a question that relates to the local area you live in, something you may have noticed, or has controversy.  A saying I like is "One measurement is worth a thousand expert opinions", which is the essence of science.  So find something to measure.  When I was in school (a long time ago) people I knew wondered about whether the local creek was clean enough.  Kids played in the creek and some people fished in it, but I thought it shouldn't foam and have a not quite clear look.  So, I got some sterile petri dishes from the biology lab, got some q-tips, and talked the local hospital pathologist into helping me.  If you need help, ask, you might be surprised, it turned out he was curious too.  Anyway, I learned a bit about how to identify bacteria and yes, the creek was polluted-bad!  I made the front page of the local paper.  I'm not saying do this, but think of a local problem and measure it.  Hope this helps.
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Try \nhttp://www.cipe.org/publications/fs/ert/e24/Agarwe24.htm