Confusion about DNA structure?

Question

In the double helix, are the two strands that cross the nucleotides??

Answer 1

The strand of DNA is a polymer of nucleotides. The backbone of the DNA strand is made from alternating phosphate and sugar residues. The sugar in DNA is 2-deoxyribose, which is a pentose (five-carbon) sugar. The sugars are joined together by phosphate groups that form phosphodiester bonds between the third and fifth carbon atoms of adjacent sugar rings. The DNA double helix is stabilized by hydrogen bonds between the bases attached to the two strands. The four bases found in DNA are adenine (abbreviated A), cytosine (C), guanine (G) and thymine (T).  

Answer 2

In molecular biology, two nucleotides on opposite complementary DNA or RNA strands that are connected via hydrogen bonds are called a base pair  Like at the junction of A + T

Nucleotides are organic compounds that consist of three joined structures: a nitrogenous base, a sugar, and a phosphate group. The most common nucleotides can be divided into two groups (purines and pyrimidines) based on the structure of the nitrogenous base. The joined sugar is either ribose or deoxyribose.

In order for the phosphodiester bond to be formed and the nucleotides to be joined, the tri-phosphate or di-phosphate forms of the nucleotide building blocks are broken apart to give off energy required to drive the enzyme-catalyzed reaction. When a single phosphate or two phosphates known as pyrophosphates break away and catalyze the reaction, the phosphodiester bond is formed.

Answer 3

a nucleotide is three things: a sugar, a phosphate group, and a base..the base is either adenine, thymine, cyosine or guanine..

the phosphate groups and sugars make up the 'strands' or like the sides of a 'ladder' if you unwound the DNA and alternate sugar/phos/sugar/phos..and the bases bond to their matching pair from the other strand..so nucleotides are just sections of DNA

not sure if this helped heres a pic



http://www.biologycorner.com/resources/D...

Answer 4

I think you're asking if the in the simple "ladder" model, "Are the rungs (steps) of the ladder representing the nucleotides?"  If so, then the answer is yes.  In these models each step of the ladder represents 2 nucleotides pairing with each other.  (A's with T's and G's with C's)

Here are a number of images of DNA:

http://images.search.yahoo.com/search/im...