Who knows anything on the double helix? I need help please.

are we talking about biology here?

And what do you need to know about it? Could you be a little bit more specific?

This link may help you
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/D/DoubleHelix.html

Thanks
Doctor Asmaa

As a matter of fact, I know quite a lot about genetics, what specific info about it are you asking for?

Phosphate, sugar, base; I do remember something from biology!

haha enigma, I am actually studying for my bio exam right now
4 types of nucleic acids
adensine
cytokine
guanine
thymine

the pairings of these chemicals are
A-T, T-A, C-G, G-C

Yes, and uracil replaces thymine when dealing with RNA.

exactly, and DNA determines the sequence and order of amino acids, which make up proteins, which is very essential for growth (building, repairing and maintainence)

Which are one of the four basic molecules of biochemistry. The others are carbohydrates, lipids, and amino acids

that is correct, and if I may suggest, DNA is one of the four MACROMOLECULES, and the rest are carbohydrates, lipids, and proteins (which are macromolecules made up of amino acids)

carbohydrates are made up of sugar units and they MUST have carbon, hydrogen, and oxygen, their chemical formula is usually C(subscript n)H (subscript 2n)O (subscript n), for instance, glucose is C6H12O6, and there are three kinds of carbohydrates: monosacchrides, disacchrides, and polysacchrides

No, DNA is not a macrolecule, but nucleic acids are, and they make up both DNA and RNA. I messed up when I said amino acid.

sugars usually end in "cose"
enzymes end with "ase"

sorry that's what I meant, nucleic acids are macromolecules, and others are carbohydrates, protein and lipids

actually no sugars usually end with "-ose"
for instance: glucose, fructose, lactose, maltose, sucrose

and carbohydrates are the most important source of energy for humans

Thanks for corecting me with the sugar thing.

Glycogen is how carbs are stored for short term use and is converted into lactic acid in animals, and a form of alcohol is plant. Lipids are used for long- term energy storage.

no problem

plants store their glucose in form of starch, and when they need it, they break the starch molecules down with amylase, a digestive enzyme also found in the saliva

you've got me beat, congradulations!

haha thank you:)

my bio exam is on thursday, so I have been studying for it since last week, wish me luck:D

good luck!

thank you, wow I am in grade 10, but I am taking grade 11 biology, it's actually quite hard, we do cellular functions, genetics, internal systems, plants, and microbes
genetics and internal systems are my favourite

Wait, what do you meen by internal systems/

just internal organ systems of humans
we did digestive, respiratory, and circulatory systems

ohhhhhhhhhhhhhhhh.
we never studied that.

I love internal systems, it's so amazing how life works, with all the hormones and enzymes and stuff
it's so interesting to learn how your food goes down and how the different muscles and valves respond and how the body sends hormones to release the different enzymes.
Are you taking grade 11 biology?
Right here, science course only specialize into different branches like biology, chemistry and physics in grade 11 and 12. school only offers general science course in gr 9 and 10, and they are so easy, no details or anything until the last two years of high school

I was in 9th grade this year, most of the people in the class were in 10th. Were I am I have to take four science classes to graduate, physical science(physics, chemistry, or physical science), earth science(or enviromnental), biology, and one other. We have something called block schedualing which means we have 8 classes a year instead of 7, and means you don't learn as much in the class since it is shorter. Then, you can also take Advanced Placement classes which give you colledge credit. In the fall I get to take environmental science and chemisty. That will be cool!

Who knows anything on the double helix? I need help please.

Soldier Of Fortune 2 - Double Helix, thats all I know :)

wow you sure learn a lot of stuff in grade 9 (or 10) biology, I remember when I was in grade 9, all we studied for the biology part of the course were cells and reproduction (sexual and asexual), and in grade 10, we mainly learned biodiversity and ecology, and some physics, chemistry and meterology, we never got into any detailed stuff in gr 9 and 10

It's the only Bio class I have to take, it's good I learned stuff!

only bio class? well I am taking biology in grade 12, I heard it's mainly going to be about biochemistry - thus much harder

North Carolina education isn't that great. I got to read alot on my own to keep up with the rest of the world.

yep reading is very important, books are very important sources of knowledge enrichment
well Ontario education system is supposed to be the hardest in all of Canada, but I still need to read extra stuff to be able to get good performanaces in school

Your lucky. I would give anything to go to a challenging school were you actually have to think and you lean alot of stuff!

yeah thanks, not a lot of students seem to like it though, because it's pretty fast-paced and they can't keep up

for some reason, I always thought that U.S. education is more difficult than Canadian education, and the competition is more intense. I mean, you have to take the S.A.T.'s in the US to get into universities, but there is no such thing here in Canada. and there are many more prestigious universities in the U.S. too like Yale, Harvard, Stanford, Princeton...

The S.A.T.'s don't determine what college you can get in, or so I hear..

Well, I live in the south (I AM NOT A SOUTHERNER!), and there are a LOT of slow people. They want every one to be equal, so they spend a lot of time helping the kids who arn't very smart, and blow of the geniuses like me. (alright, I'm exagerating about the geniuses but...) I suppose competition wise it is intense. I don't know. I haven't gotten that far yet.

oh I see, there are lots of slow people here too, and the smart or more capable people are always encouraged to seek enrichment, and some of them in grade 12 have decided to write the SAT's and go to universities in the US, and I know one person who scored exceptionally well on it, and I think he got an early acceptance to Princeton

Here they pretend like we don't exist. It's amazing how much attention you get if you're labeled Academically Gifted, and all of a sudden you start failing all of your classes!

Wait does anyone know what Royolistic actually wanted to know about DNA???

haha good question, where the heck is he?

He didn't specify what we wanted to know. Not our problem. But we could start posting random facts about it again.

good idea

I'll start with the basics.

DNA - deoxyribonucleic acid - discovered by Francis Crick and James Watson - doubled stranded structure, also known as "double helix", made of sugar, phosphate, and nitrogenous groups. a nitrogenous group forms the "rung" of the double stranded structure, and sugar and phosphate form the backbone of the double helix

RNA - ribonucleic acid - singled stranded - produces proteins

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:

http://prince.byu.edu/so_courses/so_convert/Non-courses/dev/ps100/imgs/l22_thymine.jpg

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.

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

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 :D

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?

http://prince.byu.edu/so_courses/so_convert/Non-courses/dev/ps100/imgs/l22_cytosine.jpg , 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.

http://prince.byu.edu/so_courses/so_convert/Non-courses/dev/ps100/imgs/l22_uracil.jpg, the base unique to RNA

I thought DNA was always double stranded and RNA single?
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?

hypothetically such a polymer as Quadruple stranded DNA (QsDNA) could exist if radically different base pairs were used. It would be uni-directional instead of bi-direction like dsDNA is. (that means that in DNA there are two strand running in opposite directions to each other) it would hypothetically be more stable. Perhaps in some extraterrestrial life form, as of yet no such thing exist naturally or synthetically.

So we could have several different nucleic acids occur in a hypothetical alien lifeform;

RNA
dsRNA
RNA-DNA hybrids
ssDNA
B-DNA
A-DNA
Z-DNA
qsDNA
and isn't there one called PNA as well? any more?

All very interesting stuff; thank you.
On top of all this diversity, I believe it is the case that the way codons code for various proteins could also be different in other biochemistries,

and also that many other exotic amino acids are never used by Earth life but could be utilised by alien biology.

---------------------
SF worldbuilding at
www.orionsarm.com

PNA? Please explain!

http://www.web-dictionary.org/encyclopedia/pn/PNA.html

Peptide nucleic acid.

A-DNA, B-DNA and Z-DNA are just forms of the helix, there not different chemically. Think of it as simply how the helix is twisted.

http://www.fmv.ulg.ac.be/genmol/MODGEN/Image27.gif