who knows anything about the double helix?

Hated Bio. I took AP back in sophomore year, and my teacher made us learn everything.

Nevertheless, I do find certain aspects interesting.
Here's thymine, one of the nitrogenous bases:

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Thymine is the only DNA nucleotide that RNA does not have, instead, RNA has these four nucleotides: adensine, cytosine, uracil (not contained in DNA), guanine.

 

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Ok how about someone ask a question of what they want to know?

 

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come on, this is fun, just start putting random facts about DNA or related subjects

 

What falls under "related subjects"?


translation= reads along the anti-codon side of DNA to produce an strand of mRNA
transcription= mRNA is read to produce a strand of amino acids which are a protein
replication= when DNA is copied so that the cell can divide into two sister cell with the exact same DNA

I think I got it right, or I might have flipped something around.

 

related subjects can be anything that has something to do with DNA

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bacteria reproduce using 4 methods: 1) conjugation: transfer of DNA between cells using pilus, allows bacteria to develop antibiotics resistance
2) plasmid transfer: pieces of floating DNA in the external environment enter bacteria cell
3) transduction: transfter of DNA into bacteria cell via viral injection
4) recombination: new sequence of DNA is added to the bacteria cell to produce a permanent mutation in the cell

 

eddymrsci: what city do you live in. I also am in Ontario attending highschool in Guelph.

 

I live in Sarnia in southwestern Ontario, west of Guelph I think, 11th grade after summer

 

hey im going into grade 11 too.

 

that's cool, hey you taking grade 11 biology?

 

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, one of the pyrimidines.

 

Anyone what to know why dsRNA did not remain and was replaced with DNA? I asked that question once it has a good answer.

 

What is dsRNA?

 

Don't mind DwayneD.L.Rabon he’s just a idiot.

dsRNA = Double stranded RNA
DNA is usually dsDNA, RNA is rarely ds, want to know why?

 

because RNA doesn't have thymine, but has uracil?

 

I thought DNA was always double stranded and RNA single?

 

RNA can be double stranded but it usually breaks down into the single stranded form because it doesn't have as much hydrogen bonding between the nitrogenous bases as DNA.

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, the base unique to RNA

 

yeah that's what I thought

but thanks for the explanation, facial

 

Nope RNA can be double stranded and many times has double stranded features such as hair pin loops. DNA can also be single stranded, there are a few viruses that use ssDNA there is even RNA-DNA hybrids that exist both in nature and our vital to biotech.

The reason dsRNA is not used over dsDNA is because of the ribose having a hydroxyl group on 2nd carbon (2’). This hydroxyl cause steric hindrance which prevents dsRNA from forming a B-DNA helix (The most stable helix formation) instead its restricted to A-DNA like helix (a formation only seen in DNA under dehydrated environment, less stable). (There is also the ever so weird left-handed Z-DNA for anyones reference, only seen synthetically in aromatic solutions, there is some evidence that it may exist naturally though) But even more damming is that the 2’ hydroxyl will undergo deprotonation and attack the adjacent phosphorous, the 3’ hydroxyl is normally deprotonated and attached to the phosphorus atom but in this reaction both the 2’ and 3’ hydroxyls are connected, the phosphorus is now no long able to bond to the next nucleotide and thus the RNA is cleaved. This base catalyzed hydrolysis happens spontaneously and increases in rate as pH goes up. DNA on the other hand does not have a 2’ hydroxyl, instead it has a hydrogen (hence the name “deoxy-ribose”, instead of “ribose” because of the missing oxygen at 2’) thus DNA is spared from this kind of destructive reaction and is more chemically stable for long-term storage of genetic information. Unfortunately it is energetically expensive to stripe the 2’ hydroxyl off of ribose to make DNA, this is why RNA is still used for the short term transcription and translation. To undergo these tasks RNA must remain single or partially single stranded. For DNA’s job in storing genetic information it needs to remained double strand for error correction and added stability.

 

So can you have a group of DNA or RNA with more than two strands in it?