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5

I think it is relatively unlikely that the RNA will degrade under this conditions. For the future, I would handle this differently: You can centrifuge the cells and snap freeze them in an appropriate buffer in liquid nitrogen and then store them at -80°C. I would not freeze the dry pellet, as these are often hard to re-dissolve after freezing. ...


2

PBS is isotonic to most cells, so in this buffer your bacterial cells are intact. Centrifuging them to remove PBS won't harm them it is quite standard procedure. You have to be careful after adding 2% SDS because it will lyse your cells and then the RNA contained within them will become "free" and RNAs are fragile molecules.


2

I'm assuming that you have a solution of bacteria in your buffer directly after growing them for some time, and without performing a lysis step yet. The 2% SDS step looks like it is for lysis of your cells. In that case, centrifuging the bacteria and resuspending them in lysis buffer is a very common step in many protocols. Separating whole bacteria from ...


2

Some general aspects about miRNA nomenclature in addition to canadianer's answer: mir refers to the pre-miRNA whereas miR refers to the mature form mir-x-y mir-x-z for example mir-1-1 and mir-1-2 refer to different precursors that give rise to same mature miRNA (i.e. miR-1). These different precursors can be regulated differently. The mature miRNA ...


1

let-7 is a miRNA family (let stands for lethal) and, in fact, was one of the first to be discovered (in Caenorhabditis elegans). let-7a is but one of many members of the family, with orthologs in many species. It seems rare in biology that established names are changed to match newer nomenclature, though I can't say for sure if that is why many (but not all) ...


11

Th reason for this is that for the third base of the tRNA non-Watson-Crick pairing is allowed. This phenomenon is called "Wobble base pairing". See the figure (from here) for illustration (from here): If you have a look at the codon table for amino acids, than the variation in the code for one amino acid mostly happens on the third position (from here): ...


3

Watson-Crick base pairing can be violated by wobble base pairing. The 5' of the anticodon has more freedom in binding, that is why, for many amino acids, the last part of the codon has more possible characters.


5

Not very common, and not found so far in nature, but they exist and are called deoxyribozymes. Additional information: Deoxyribozymes are the equivalent of ribozymes in the DNA world and can function as catalysts for different biochemical reactions, such as DNA cleavage. While DNAzymes (short name) were synthesized in a laboratory context (In-vitro) and ...


2

MicroRNA (miRNA) are gene-regulatory RNAs that are loaded onto the RNA-induced silencing complex (RISC) and interact with partially-complementary targets on mRNA to suppress protein expression. The miRNA is originally double-stranded and composed of strands about 21 nucleotides long; on loading onto RISC, one strand is degraded and the other, the "guide" ...


2

21joanna12, look into snRNPs. These are parts of the splicosomal apparatus and some of them (the U1 and U2, U11 and U12 snRNPs) are also the guideposts that bind near the splice junctions at the end of introns. These help guide the splicing apparatus to the splice sites. There are also proteins that bind RNA and interact with the splicing apparatus to ...


4

Short answer: Yes, you can. Usually these are coupled systems for transcription and translation. For these you clone the gene of interest into a vector which contains a prokaryotic promoter which is then used to generate the mRNA in the tube. This mRNA is then translated in the second step into a protein. This works very well, but the protein is missing ...


4

This question can't be answered with a simple yes/no, but I would say that the analogy of DNA being the "code" used by cells is a reasonable one, if taken with a number of other considerations. DNA function When Watson and Crick first described the structure of DNA (being a double-stranded sequence of the nucleotides Adenine, Cytosine, Guanine and ...


5

Start and stop codons are instructions for the ribosome to start and stop protein synthesis, respectively. The region between the start and stop codon (inclusive of them) is called ORF (open reading frame) or sometimes CDS (Coding sequence). Why does ribosome need explicit instructions for start and stop? Ribosome recognizes an RNA as a mRNA if it has ...



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