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The majority of molecular recognition (if not all) occurs either by site recognition via favourable chemistry, by geometry or both. In vivo, mistakes in DNA replication via DNA polymerase occur when the wrong bases are inserted into the new stand at the 3' end. There two mechanisms to make sure the code is replicated correctly and without error 1. Watson-...


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This is in between an extended comment and an answer. What do you mean by "Natural"? The question makes no sense as the term "natural" isn't properly defined. (I am voting to close as unclear). For example, if you go to an area where there is "naturally" a high radioactivity, this will increase your mutation rate. Is this a natural way to change your ...


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The region in the mRNA upstream of the start site is 5' UTR; 5' untranslated region. Sometimes, UTRs have regulatory functions. Or, the UTR mutation might just be along for the ride, and have no effect at all. You generally can't look at a non coding SNP and tell if it's functional with no other information unless it messes with one of the first few bases ...


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When UV light is on your skin it has to go through the cell membrane and to the membrane of the core. So it looks like that the DNA is protected. I don't understand what you mean by membrane of the core (perhaps nuclear membrane) but yes there is cell membrane and other cytosolic components. You should, however note that not all cells are spherical; ...


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UV Rays kill the cells by damaging the DNA. UV lights do not disrupt the cell membrane. If a cell is exposed to UV light, it creates THYMINE dimers (bond). Thymine dimers are the actual disruption in the kinks of DNA. UV exposure to skin is proportional to the cell damage. P53 is a gene product which takes care of fixing cell damage. However it has a ...


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Your understanding of DNA is correct. DNA is a heteropolymer of monomers called nucleotides and each nucleotide is made up of a sugar (deoxyribose), phosphate and a "base" (A, T, G, C). As you already know, DNA is organized as a double helix with the Watson-Crick pairing rules. A chromosome contains a single DNA double helix. Many organisms have multiple ...


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Interpretation of the question You ask two things: 1. the number of nucleic acid bases that constitutes a gene, 2. (implied) how the size of genes are defined. The first question appears strangely naïve, but the second suggests this may be a misunderstanding. I therefore intend to start there. How are the limits of a gene defined? Genes are defined in ...


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Is there an agreed-upon definition as to how many nucleobases constitute a gene? If not, why not? There is no such definition. A gene is a region of the DNA that is transcribed. Typically a gene should have a transcription start site dictated by a promoter and a transcription stop site marked by termination signals (like terminators and poly-A signal ...


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How are gene size defined? DNA is made of 4 nucleotides A,T,C and G. A series of such nucleotide make up any section of the genome including the genes. The number of nucleotide in a gene is what we call the gene size. Of course, one might discuss on the definition of the exact beginning and end (and methods to determine them) of a gene but this is a ...


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You ask initially about the “sense” and “antisense” strands of DNA. These terms are explained in the Wikipedia reference entitled ‘Sense strand’. This states what you appear to be already aware of, that: “The sense strand is the strand of DNA that has the same sequence as the mRNA, which takes the antisense strand as its template during transcription…” ...


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I would add this as a comment to your question but do not have enough reputation. A simple look at Wikipedia (which is a very good source for general questions like these) would have provided you with an answer. I just did this to see how long it would take if I did not know the answer. It was about 20-30 seconds. Protein synthesis: Transcription In ...


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Seeds are generally made in order to stand dry/cold conditions. I don't see any reason to believe that the DNA got damaged during freezing (that could cause mutation and phenotypic changes). So, if they have germinated, the plants should not be any different from the controls.


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It depends on the animal, some can get it, others cannot. Down syndrome is the result of an extra copy of the twenty first human chromosome. So, it is a rather humanly genetic problem. However, the closer an animal is to humans, the greater the chance of it being at risk of suffering from down syndrome. There have been several chimpanzees found ...


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Animals can be generated with genetic defects similar to Down Syndrome, but not that exact condition, except in the case of great apes. Down Syndrome is a kind of defect called a chromosomal abnormality, meaning that either there is an extra chromosome or an excessive repetition of the same genes on a particular chromosome. In the case of Down Syndrome, ...


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These terms are quite similar and, for many, confusing: Chromatin Chromosome Chromatid But they are not synonyms. According to "Molecular Cell Biology", Lodish, 4th ed: Chromatin: Complex of DNA, histones, and nonhistone proteins from which eukaryotic chromosomes are formed. Thus: Chromosome: In eukaryotes, the structural unit of the genetic ...


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You call it a thought experiment but something like this has actually been done. Not entirely similar as they don't switch 2, but still they replace a codon. An overview: https://en.wikipedia.org/wiki/Expanded_genetic_code Big thing: in the two articles leading up to this one they replaced all 314 UAG stop codons in E.coli K12 and used the now unused UAG ...


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Hasn’t your question already been answered by those organisms (and organelles) that have a different genetic code from the standard genetic code (originally known as ‘universal’)? Essentially they have performed the experiment for you by developing machinery to decode mRNA differently (transfer RNAs with appropriately different anticodon/amino-acid accepting ...


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On one hand, designing an experiment which would kill (and resurrect) a cell is not possible: once a cell malfunctions, it's likely damaged beyond repair. However, other than that I don't think this experiment kind of cannot actually be done. You would just have to simultaneously expose different cultures (grown in the same conditions) to different inserted ...


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I suggest you to try Recursive Directional Ligation. It is meant to do exactly what you are aiming for, i.e. to "polymerize" short DNAs into a longer one. You can find the protocol here http://pubs.acs.org/doi/abs/10.1021/bm015630n


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The scope of this question is too wide to be answered on Biology SE. However I will give you very brief answers to your questions (as I have rephrased them) and point you towards some sources of basic information on the Internet. After reading these you may wish to return with more specific questions. I have also briefly summarized some of the problems which ...



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