Questions tagged [rna]

RNA, or ribonucleic acid, is a biological macromolecule made of nucleotides used in cells to convey genetic information to protein. RNA also plays a role in catalyzing certain biological reactions as well as carrying genetic material in some viruses.

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109
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109k views

Why is thymine rather than uracil used in DNA?

What is the advantage gained by the substitution of thymine for uracil in DNA? I have read previously that it is due to thymine being "better protected" and therefore more suited to the storage role ...
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4answers
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Why do eukaryotic organisms have introns in their DNA?

We touched on introns and exons in my bio class, but unfortunately we didn't really talk about why Eukaryotes have introns. It would seem they would have to have some purpose since prokaryotes do not ...
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How is RNAse contamination in RNA based experiments prevented?

Does anyone have any suggestions to prevent RNAse contamination when working with RNA? I tend to have issues with degradation regardless of whether I use DEPC treated / RNAse free water and filtered ...
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4answers
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Why deoxyribose for DNA and ribose for RNA?

Why is DNA made out of deoxyribose and RNA made of ribose? Why can't they both use ribose or deoxyribose? I think that the deoxyribose gives an advantage in storing genes, the job of DNA and ribose is ...
21
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3answers
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How long can I store extracted RNA?

If I extract RNA from a (leaf tissue) sample using a one-step phenol:chloroform extraction, how long can those samples be stored at -80°C? And how many times can I defrost and refreeze them before ...
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What is the explanation for the smaller number of tRNA than codons?

Translation, or decoding, of the four-nucleotide language of DNA and mRNA into the 20–amino acid language of proteins requires tRNAs and enzymes called aminoacyl-tRNA synthetases. To participate ...
15
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2answers
377 views

Can methylation from DNA get copied to RNA during transcription?

Methylation on gene-body and 3'UTRs if copied to mRNA can potentially regulate post-transcription modifications or expression regulation. But I'm not sure if they are maintained after transcription or ...
15
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1answer
784 views

Can DNA act as a translation substrate?

I get conflicting answers. One would think if it was true, it would be rather seminal and widely known. There are papers from Khorana[1], Holland[2], and Bretscher[3] (late 60s) that suggest that it ...
14
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What implications has the missing 2'-OH on the capability of DNA to form 3D structures?

The chemical difference between RNA and DNA is the missing 2'-hydroxyl group in the nucleotides that build DNA. The major effect of that change that I know of is the higher stability of DNA compared ...
14
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2answers
3k views

Why is uracil, rather than thymine, used in RNA?

This question was posed on SE Biology some time ago, but all the answers, including the accepted one, answered a different question instead: “Why is thymine, rather than uracil, used in DNA?”. I ...
13
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2answers
371 views

Are codons that map to the same amino acids interchangeable?

From wikipedia, in the section on the RNA codon table, I see a mapping between codons and amino acids. There, Valine is related to GUU, GUA, GUG, GUC. Does it mean in the same context that these ...
13
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2answers
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Why is thymine not incorporated into mRNA?

I am aware that in transcription uracil bonds to adenine and not thymine. But what is it that actually prevents thymine from bonding to adenine in transcription, that is not present in replication?
13
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2answers
349 views

Can DNA produce ribozyme-like structures?

RNA is known to act as an enzyme via its ability to fold itself in specific ways. Is DNA capable of such structures? Or is it some biochemical reason stopping the folding? Have they been observed in ...
12
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What is the function of the RNA primer in DNA replication?

During DNA replication, RNA primase puts an RNA primer in the lagging strand. What is the function of this RNA primer? Why can't the enzymes put DNA fragments directly?
12
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1answer
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First RNA polymerase-mRNA

We know that RNA polymerase produces mRNA by reading DNA strand. Which enzyme produces the first RNA polymerase if other RNA polymerases are synthesized in the same way like other enzymes(proteins) ?
12
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1answer
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Why does RNA adopt an A-form helix?

RNA is known to form an A-form helix, while DNA generally forms a B-form helix under physiological conditions. From left to right: A-form DNA, B-form DNA, Z-form DNA. Image created by Richard Wheeler ...
12
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2answers
420 views

Biopython - Big Discrepancy Calculating RNA melting Temperature over Literature

I experience big discrepancies when calculating melting temperature of RNA 7-mers with Biopython over values generated by a popular algorithm. I tried the nearest neighbour algorithm with RNA and ...
12
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1answer
533 views

Which sequence characteristics influence the transcription efficiency of T7 polymerase?

The T7 polymerase doesn't transcribe all sequences equally well, the transciption efficiency can vary widely for different sequences. One well known requirement of the T7 polymerase is that the ...
11
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2answers
10k views

How do I clean phenol contaminated RNA without losing any of the sample?

I recently extracted RNA from developing plant leaves for the first time, as part of a very long and intensive experiment. The samples were extremely precious because of the amount of effort that went ...
11
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1answer
58k views

Absorption ratios 260/280 and 260/230 for RNA

I extracted RNA from different cell lines, an I want to perform reverse transcription and then PCR. To get good results, in which range should the absorption ratios 260/280 nm and 260/230 nm be? And ...
11
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3answers
10k views

Is there any virus that contains both DNA and RNA in its genome?

It is known that viruses contain DNA or RNA- either one and not both. I came across a question: Which virus contains both DNA and RNA?
11
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Does RNA polymerase move around DNA or does DNA rotate benath the polymerase?

I'm thinking of the human genome specfically, but more general answers are welcome. As RNA polymerase moves along the DNA helix it follows a single strand. The two DNA strands are unwound locally ...
10
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1answer
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Why is DNA double stranded and RNA single stranded? [closed]

Why is DNA present as a double helix structure and RNA as a single helix? What causes the difference between them? What are the practical physiological differences between dsDNA and ssRNA? How are the ...
9
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3answers
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Are non-coding RNAs introns?

I am slightly confused as to what part of the genome codes for non-coding RNAs. Is it the introns? This would make sense to me as to why they are not transcribed as the introns are not transcribed. Or ...
9
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1answer
348 views

How many RNA-binding proteins can simultaneously bind on a single mRNA?

Typically, how many RNA-binding proteins can simultaneously bind to a single mRNA? Or said differently, how many "binding sites" does an mRNA have? What order of magnitude? I am interested in RNA ...
9
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2answers
5k views

How to find miRNA binding sites on a specific gene?

I am trying to find miRNAs that bind to the 3'UTR of a specific gene. What is the best way of doing that (that is, with a good scoring analysis that is most commonly used by researchers in this area)? ...
8
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1answer
5k views

How does a single-stranded RNA bind to a double-stranded DNA to form a “triplex structure”?

If you have a single-stranded RNA that is complementary to a double-stranded DNA, how do they interact to form what my prof. calls a "triplex structure"? e.g. ...
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2answers
1k views

What stops messenger RNA from binding to itself?

Since mRNA is single-stranded, and (mostly) floats freely within the cytosol, what stops it from folding onto itself (like DNA) and preventing transcription?
7
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2answers
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What's the longest transcript known?

What's the longest functional transcript known? I'm wondering about RNA length post splicing, so not including introns.
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Why is an initiator tRNA required, distinct from the methionine tRNA used in elongation?

I'm confused by why there is a need for different tRNA-methionine complexes for translational initiation and elongation. This paper mentions that It is important that each type of methionyl tRNA ...
7
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1answer
5k views

Purpose of poly(A)+ RNA?

I am learning RNA-seq analysis. I always encounter this phase "poly(A)+ RNA". After searching, I got this: "Most messenger RNAs contain a poly(A) tail, while structural RNAs do not. Poly(A) selection ...
7
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2answers
577 views

What are some (bioinformatic) methods to characterize potentially novel gene transcripts?

I am working with a few novel transcripts of genes- before I confirm their existence experimentally, I would like to perform some bioinformatic analysis. I have already considered coding potential, ...
7
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2answers
3k views

Why do DNA and RNA have the functions they have?

I know that there are two most important directions of genetic information transfer in living organisms: DNA->DNA and DNA->RNA. The first is replication, and the second is transcription. I wonder if ...
7
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2answers
429 views

Use cases of RNA secondary structure prediction

I'm an undergraduate currently writing a thesis on RNA secondary structure prediction, specifically building upon analysis done by the RNAStructure and Unafold software packages by modifying certain ...
7
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2answers
403 views

Naming convention of miRNAs

I'm trying to understand naming convention of miRNAs. I've found the wikipedia article about it nomenclature Based on it, I try to figure out what is hsa-let-7a. As far as I understood, hsa refers to ...
7
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1answer
994 views

How much total RNA can be extracted from Drosophila brain

I am wondering how much total RNA could be extracted from a single D. melanogaster brain. I could not find this information from the literature. The closest hit was this paper, that claims that 16-21....
7
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1answer
400 views

How significant is RNA degradation with removal of cap/polyA's in eukaryotes, or UTR's in prokaryotes?

Question is rather self-explanatory, but segmented into two parts. I'm attempting to make use of a repression system that employs cleaving RNA at specific areas with ribozymes with the intent of ...
7
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1answer
65 views

circulating microRNAs are functional?

In plasma and other body fluids, miRNAs can be found. They not only originate from dying cells but also from active secretion and are usually 'packed' into vesicles/lipo-proteic structures (i.e. ...
7
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1answer
635 views

Double stranded nucleic acids are more 'durable' than single stranded nucleic acids?

I'm struggling with a question I've been asked. "Why is double stranded genetic material more 'durable' than single stranded one?" I know that double stranded genetic material is more stable due to ...
6
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3answers
435 views

Are some non-coding RNA spliced?

Are some non-coding RNA spliced like mRNA? I tried to find some information but I don't find anything...
6
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3answers
5k views

Mutation That Loses Stop Codon

Someone asked this in my class and my instructor wasn't sure in her answer, doesn't anyone know what happens in protein synthesis if a mutation causes mRNA to not possess a stop codon? Would the ...
6
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2answers
1k views

Reverse transcription PCR optimization

What is the ideal amount of RNA to use for the RT? and how much cDNA to use then for the PCR? I did RT with a solution of RNA of 0.36 ug/ul. Then for my PCR I used 1 ul of the cDNA obtained and used ...
6
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2answers
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Does ethanol destroy RNase?

I've gotten conflicting advice on this: some people believe one can remove RNase contamination simply by spraying the bench, pipettes, gloves, etc. with ethanol. Others think ethanol does not destroy ...
6
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2answers
174 views

Can we attack viruses by attaching proteins and such to their shells?

Haven't looked into this to very long, but an initial search didn't return anything. HIV uses certain co-receptors to enter our cells. Could we flood the blood stream with specially designed ...
6
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2answers
123 views

How predictably will RNA polymerase not transcribe repetitive sequences?

I am working on an (expensive) synthetic construct, which happens to have many "repetitive" sequences within it that are integral to its function. Primarily, the two sequences that are worrying me are:...
6
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1answer
359 views

Is there a double helix RNA?

I wonder what is its function and if it can be the genetic material for a living organism. If not, why?
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2answers
6k views

Very high 260/230 absorbance ratio of an RNA sample

After my most recent RNA extraction, the RNA samples had very high 260/230 absorbance ratios, (ranging from 5 to 25). I've never gotten numbers like this and I know the ratio is supposed to be ~2 in ...
6
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5answers
20k views

How much nucleoside triphosphate is required to form one peptide bond during protein synthesis?

I'm trying to find out how many molecules of nucleoside triphosphates (ATP, GTP, UTP and/or CTP) it takes to release enough energy to link two amino acid monomers together with a peptide bond, ...
6
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1answer
146 views

Can two hammerhead ribozymes simultaneously cleave each other?

I am working on a project in which an XOR gate is being built by having two hammerhead ribozymes simultaneously cleave each other when both are expressed, but have these ribozymes cleave a target ...
5
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2answers
2k views

What makes DNA helical?

Why isn't DNA like RNA; why isn't RNA like DNA, that is, helical? Why are RNA chains straight?