DNA Basics

Discussion of all aspects of biological molecules, biochemical processes and laboratory procedures in the field.

Moderators: honeev, Leonid, amiradm, BioTeam

Post Reply
User avatar
cytochromeP
Death Adder
Death Adder
Posts: 73
Joined: Wed Apr 06, 2005 2:17 pm
Location: Third Rock From The Sun
Contact:

DNA Basics

Post by cytochromeP » Fri Sep 16, 2005 8:39 pm

Why are the two strands of a double stranded DNA molecule anti-parallel?

It would be great if someone could support their reason using some real data - like pointing me to a url or some great book which gives the reason :)
Know thyself.

loupass
Garter
Garter
Posts: 8
Joined: Thu Jun 09, 2005 8:38 pm

Post by loupass » Wed Sep 21, 2005 9:09 pm


User avatar
cytochromeP
Death Adder
Death Adder
Posts: 73
Joined: Wed Apr 06, 2005 2:17 pm
Location: Third Rock From The Sun
Contact:

Thnx

Post by cytochromeP » Tue Sep 27, 2005 5:29 pm

Thnx loupass.

I wont say that i am thoroughly satisfied but now atleast I have two new sources to look up answers from.

Thnx again :D
Know thyself.

User avatar
microbe hunter
Garter
Garter
Posts: 16
Joined: Sat Oct 01, 2005 4:27 am

Re: DNA Basics

Post by microbe hunter » Sun Oct 02, 2005 2:17 pm

the diameter of a b form dna helix is 20 angstrom.so in that space only a bicyclic purine and monocyclic pyrimidine can fit in correctly...and thus the strands bcome complementary.....then they obviously have to be antiparallel rite???

User avatar
cytochromeP
Death Adder
Death Adder
Posts: 73
Joined: Wed Apr 06, 2005 2:17 pm
Location: Third Rock From The Sun
Contact:

Re: DNA Basics

Post by cytochromeP » Sun Oct 02, 2005 3:08 pm

microbe hunter wrote:the diameter of a b form dna helix is 20 angstrom.so in that space only a bicyclic purine and monocyclic pyrimidine can fit in correctly...and thus the strands bcome complementary.....then they obviously have to be antiparallel rite???


Well the logic u have applied is indeed correct. But the question is not how the strands 'actually' are in DNA. Instead the question is - can one have a DNA molecule in which the two strands a not anti-parallel?

Moreover, the DNA fibre being 20A thick is a consequence of the base pair being made up of a purine and a pyrimidine and not the other way round. Causality.
Know thyself.

User avatar
cytochromeP
Death Adder
Death Adder
Posts: 73
Joined: Wed Apr 06, 2005 2:17 pm
Location: Third Rock From The Sun
Contact:

Re: DNA Basics

Post by cytochromeP » Mon Oct 03, 2005 1:29 pm

cytochromeP wrote:Well the logic u have applied is indeed correct.


Oops!! Sorie that I missed it first.
The logic you applied is indeed flawed.
Well the logic you applied sure does explain why a DNA base pair is made up of one Purine and one Pyrimidine. But this does'nt imply that the two starnds are anti-parallel. They are called anti-parallel becoz of the opposite orientation of riboses in the two strands.
Know thyself.

Post Reply

Who is online

Users browsing this forum: Google Adsense [Bot] and 9 guests