The Instigator
Con (against)
0 Points
The Contender
Pro (for)
6 Points

is DNA really double helix?

Do you like this debate?NoYes+1
Add this debate to Google Add this debate to Delicious Add this debate to FaceBook Add this debate to Digg  
Post Voting Period
The voting period for this debate has ended.
after 1 vote the winner is...
Voting Style: Open Point System: 7 Point
Started: 1/18/2012 Category: Science
Updated: 4 years ago Status: Post Voting Period
Viewed: 3,486 times Debate No: 20473
Debate Rounds (5)
Comments (13)
Votes (1)




guys i found that what is known as dna in real life is quite different from the model of dna.

so what is the actual shape of dna? why should i believe dna exist?

real life DNA

model DNA

i argue that dna is not double helix therefore does not exist. pro will argue that dna is double helix and therefore exist.


I assume that this round (1) is for acceptance only. I ask my opponent to please tell me what rounds are for main arguments, but if he doesn't I will assume that Round 2-3 is for arguments, 4 is for rebuttals, and 5 is for rebuttals and closing. Plus, I just finished a unit at my school on Genetics and DNA, so I will put my knowledge to work. Good luck Pro.
Debate Round No. 1


i agree with pro

round 2-3 is argument, 4 rebuttal, 5 conclusion.i already posted my argument.


DNA is deoxyribonucleic acid. It is made out of nucleotides. Nucleotides are made out of a sugar group, phosphate group, and nitrogen base, and the nitrogen base may be Thymine, Adenine, Cytosine, and Guanine. The former two pair together and the latter two pair together.

DNA Background and Proof

The DNA is a double helix and is a nucleic acid, and contains the genetic instructions used in the development and functioning of all living organisms. Viruses are the only known exception, but still aren't a true exception because viruses are not living. [1]

Nucleotides: Made of sugar group, phosphate group, and nitrogen base.
DNA: Made of nucleotides.

The model that Pro presented as the "model" image is real, but is a computer generated image. DNA can be better described by the link [2] The strand that you always see in DNA that twists is called the DNA strand. This is also known as the DNA backbone. It is composed of a phosphate group (represented by circles) and by a 5-carbon sugar (also called a sugar group; represented by pentagon). Both the phosphate group and the 5-carbon sugar form together the
DNA sugar-phosphate backbone, which is the "band" you see that forms the exterior of the DNA models, [3]

Then, the in the model you see that, right after the backbone of DNA, you have the groups of two that pair up and look like a small rectangle, and always pair up A-T, T-A, G-C, or C-G. These letter are the nitrogen groups, which I said in the beginning. They can also be called
nitrogenous bases [2] Two of these have two rings instead of one, and are called Purines. The others are called Pyrimidines. [3]
Now, all of this DNA that I have been talking about is a double helix and has is
UNIVERSALLY accepted by the Scientific community, and I have just PROVED you wrong, DNA is a Double Helix. The people who discovered the double helix, James Watson and Francis Crick, tested numerous experiments to prove that DNA is a double helix. They used the x-rays from earlier scientist Rosalind Franklin, and they found a x-ray pattern. Then, they concluded later that DNA was a double helix, in which two strands were wound around each other. [4] [5]

DNA is Double Helix: Main argument

Your picture is of, I assume, a chromosome. I will get back to that soon.

Regarding all of the background information on DNA that I gave, DNA is a double helix made out of nucleotides.

Your Picture is right, but DNA is a Double Helix Still

When the cell is just doing its necessary functions, DNA is in the shape of a double helix. It has been proved, and I proved it about in the DNA background section. However, later, before cell division, DNA condenses up [4] [5] and then wraps around histones (type of protein). The histones coil up in massive amounts to form the chromatids in a chromosome. Then, the
chromosome is visible when an electron microscope is looking at a cell during mitosis. Now, the picture you are showing IS A CHROMOSOME. Chromosomes in humans look like on the link for the most part [6], besides the 23rd set of chromosomes (sex chromosomes). However, chromosomes vary among organisms. Some look like human chromosomes on link 6, and some, like the E Coli Chromosome (only has 1) look much different and may even be of different structure. [7] Still, DNA is really a double helix and I have proved it. The chromosomes you see are made up of DNA which is made up of much smaller and is a double helix in form, as you can see in the Pictures on the link [3] DNA is a double helix, and still is even when it is condensed in a chromosome. [3] The only time DNA is not a double helix is when DNA is being copied by the DNA enzyme Polyermase during the cell stage of Interphase (more specifically the S Phase of Interphase). Then, the DNA is put back into a double helix form. [4] Vote CON


[4] "Biology" By Miller/Levine. Prentice Hall

Debate Round No. 2


my point is that the DNA seen through electron microscope does not match with the double helix picture.

then either the model is wrong or the thing identified as DNA by electron microscope is not DNA.

what is the case here?

please don't say that scientists approve it. use your own intellect to understand my point.


Chromosomes in Humans/ E Coli

Chromosomes: Any of several threadlike bodies, consisting of chromatin, that carry the genes in a linear order.

C1: I couldn't find that picture that you have anywhere else. Since you give scarcely any information about it, I have to assume that it is a chromosome. However, it is not a human chromosome. I give a link below to a picture of a karyotype, which is a snapshot of all of the human's chromosomes at once, collected by observing nuclei under an electron microscope.

Human Chromosomes: [1]

However, other organisms, such as E Coli, have different amounts and different looking chromosomes. For example, once again, E Coli, which is a prokaryote, and a relatively simple organism.

E Coli Chromosome: [2]

C2: DNA is a double helix nucleic acid. I have a link that is awesome at showing you the model of the DNA double helix and everything I described in Round 2 on DNA: [3]

You have been saying "DNA looks like my link. Not like a DNA double helix". This is your main attack, and the attack that I haven't been using my intellect (ha ha). My sources are for pictures for the voters and us to see.

DNA (double helix) = Content of Chromosomes

DNA double helix > Wrapped around Histones > Called Nucleosome > Large coil of nucleosomes called Supercoil > Supercoils form Protein Scaffold > Many protein scaffolds form Chromosome [4] [6]

With C3, I have showed you the relationship between the DNA double helix and a Chromosome. I also have a few links for picture purposes. [5] [6] [4] The DNA wraps around histones, which are then called nucleosomes, and the coils of nucleosomes are called a supercoil, and the supercoils form protein scaffolds, which form chromosomes. It can be concluded from the Law of Syllogism that DNA double helix >> Chromosome. [7] (definition of Law of Syllogism)

So, Chromosomes, which are the ones on my link 1, are made at their very core of DNA, which is a double helix. This is my intellect for you. The structure of the DNA helix is [3], and it makes up chromosomes [6] (shows relationship) Now, as I have stated, other organisms have different looking chromosomes. Still however, their chromosomes, even though they look different like the E Coli chromosome, are made up at their basic level DNA, which is a double helix.

Plus, the reason for all of these links is for the pictures so you and the voters can understand my case better. So YOUR PICTURE IS A CHROMOSOME made OUT OF tightly coiled DNA which is A DOUBLE HELIX. You case is refuted.

Additional Proof:

Rosalind Franklin studied DNA to find out its model. She used a technique called X-ray diffraction to discover what the structure of the DNA molecule looked like. Her work shows that DNA strands are twisted around each other and that there are two strands in the structure. The link has a picture of one of her results: [8]





[4] "Biology" by Miller/ Levine. Prentice Hall





Debate Round No. 3


see this above 2 pics .

the double helix model does not match with real life pic of DNA under electron microscope.

thats my point.


CI: Chromosomes are made up of DNA

My opponent has no true case. His case, is that DNA, as shown by google searching, that DNA looks like the pictures on his "real DNA" links. However, these results are not real. These photos, on his link, are mainly pictures of chromosomes.

Chromosome: Any of several threadlike bodies, consisting of chromatin, that carry the genes in a linear order

--picture of chromosome:

DNA: Deoxyribonucleic acid: an extremely long macromolecule that is the main component of chromosome
material that transfers genetic characteristics in all life forms, constructed of two nucleotide strands coil around each other in a ladderlike arrangement with the sidepieces composed of alternating phosphate & deoxyribose units
and the rungs composed of the
purine and pyrimidine bases adenine, guanine,
cytosine, and thymine:
the genetic information of DNA is encoded in the sequence of the bases and is transcribed as the strands unwind and

--picture of DNA at core:

I have shown that DNA is not the same as Chromosomes, and that Chromosomes are made out of DNA.
Chromosomes are the genetic structures that contain the genetic
information that humans give to their offspring. DNA is the basis of this structure. Compare it to a computer. The computer is the main structure, but is made out of computer parts (i.e. motherboard, graphics card, RAM, CPU, etc.) Compare this example to our debate. It is similar to saying, "Is a motherboard really made of circuit paths?" then showing us pictures of a computer case.

C2: DNA (double helix) >> Chromosomes

DNA IS A DOUBLE HELIX! When in a nucleus of cell, DNA is not visible. However, when
DNA is about to enter cell division and mitosis (division of nucleus), the DNA condenses and, as I showed us in round 3, how DNA coils up and forms a chromosome, which is what you are showing me a picture of. Your pictures are of chromosomes my friend! And I have proven numerous times that DNA coils up to form these chromosomes! You are basically showing us pictures of non-human chromosomes, and then saying DNA is not a double helix! You have no case! I have described what the similarities and differences between DNA and Chromosomes are, and how DNA coils
up to form chromosomes. Therefore, Pro should automatically win!

Here I have a picture describing the similarities between DNA how it coils up to form a Chromosome. The second picture shows a model of DNA that proves it is a double helix:

<< The Model of DNA

Debate Round No. 4


xxx200 forfeited this round.


As I have said, my opponent has only showed pictures of chromosomes of non-human chromosomes. I have proved that chromosomes are made out of coiled up DNA shown by x-ray diffraction, and by a chart. My opponent has not refuted this in any way, and Pro automatically should win.

Picture showing DNA double helix under x-ray diffraction:

Debate Round No. 5
13 comments have been posted on this debate. Showing 1 through 10 records.
Posted by vmpire321 4 years ago
LMFAO@Bench. I'm guessing he is some 10-year-old who thinks he is smart and joined DDO... Obvious fake age much?

Or perhaps he really is this stupid.

Or perhaps he is just a troll.
Posted by imabench 4 years ago
How is xxx200 27 years old..... No 27 year old can be this unintelligent
Posted by vmpire321 4 years ago
No. Someone should make an account called "Protra" and challenge Contra. xD
Posted by PeacefulChaos 4 years ago
Someone should create an account with the username called, "Pro", then take the Con side of the debate.
Posted by vmpire321 4 years ago
Yes Con(tra) is failing..

LOl that never gets old for me. Expect to see that for a while
Posted by vmpire321 4 years ago
Yes Con(tra) is failing..

LOl that never gets old for me. Expect to see that for a while
Posted by Contra 4 years ago
What is sad that Con can't construct a real argument?
Posted by vmpire321 4 years ago
This is sad.
Posted by Maikuru 4 years ago
Yeah, Pro. Use your intellect!
Posted by Fluer 4 years ago
so just because our hearts are not shaped like the hearts on a suit of cards then we don't have hearts ??
1 votes has been placed for this debate.
Vote Placed by Ron-Paul 4 years ago
Agreed with before the debate:-Vote Checkmark-0 points
Agreed with after the debate:-Vote Checkmark-0 points
Who had better conduct:-Vote Checkmark-1 point
Had better spelling and grammar:--Vote Checkmark1 point
Made more convincing arguments:-Vote Checkmark-3 points
Used the most reliable sources:-Vote Checkmark-2 points
Total points awarded:06 
Reasons for voting decision: Wow. One, this guy needs to extend his arguments and use sources, and two, he shouldn't agree with his opponent on the whole argument. Vote Pro!