Question

polynucleotide chain of dna contains

Answer 1

Definition

DNA and RNA are essential in making you you. But what makes DNA DNA? Well, DNA and RNA are made up of organic molecules of a particular composition called nucleotides. If you had a toy tower made of Legos, DNA would be the tower and nucleotides the individual Legos.

A polynucleotide, therefore, is a chain of nucleotides. RNA is a polynucleotide, and DNA is a pair of polynucleotides. In this lesson, we'll learn how nucleotides join together to make a polynucleotide strand.

Structure

Think of a string of flags - like Tibetan prayer flags or even the flags you might see at a car dealership. The string is like a backbone that holds the flags together. A polynucleotide has a backbone, too. This polynucleotide backbone is made of the sugar and phosphate parts of nucleotides, so we call it a sugar-phosphate backbone.

Just as a strand of flags can have a sequence - say 'red, red, blue, red, green...' a polynucleotide strand has a sequence of bases called nitrogenous bases. Instead of colors, the bases have different chemical names. In DNA, the bases are adenine, guanine, cytosine, and thymine. This means that a polynucleotide's sequence might look like:

ACGTCGTATATCGTAGCTGTCAGTCGAGTAC...

RNA's polynucleotides are a little different; instead of thymine, they have uracil. They also have a different type of sugar in their backbone.

How Nucleotides Join Together

Each nucleotide has a base, a sugar, and a phosphate. An enzyme called polymerase joins the sugars to the phosphates. DNA and RNA each has its own polymerase.

The polymerase adds new nucleotides to the bottom of the strand, which we call the 3' end. The name comes from where the phosphate group attaches: on the sugar's third carbon. The top of the strand is called the 5' end; the phosphate group attaches to the sugar's fifth carbon.

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Answer 2

See, in the basic structure of the DNA,

two polynucleotide chains are there. It is called as polynucleotide chains since they are composed of monomer units.

Each nucleotide contains one of for nucleotide bases cytosine , guanine, adenine, thymine.

And a sugar called deoxyribose.

And a phosphate group.

Adenine (A) always makes 2 weak hydrogen bond with thymine (T).

Cytosine (C) always makes 3 weak hydrogen bonds with guanine (G).


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