Give a detailed yet easy to understand explanation about what DNA is and its job (factors etc.) Also, please include chromosomes and genes. A better understanding?

I need a better explanation on DNA. I want a better understanding of DNA and how everything works (the bases and pairs etc.) Thank you for your understanding and consideration!

1 Answer
Jun 11, 2018

DNA (deoxyribonucleic acid) is basically a nucleic acid.


Alright, then what's a nucleic acid?

It's basically what we call as polynucleotides. Nucleic acids (like DNA and RNA) are polymers (polynucleotides) , made of repeating sub-units which are basically your nucleotides.

Alright, then what's a nucleotide?

A nucleotide is basically the monomer of all nucleic acids, and we have five of them.

  1. Adenine (A)
  2. Thymine (T)
  3. Guanine (G)
  4. Cytosine (C)
  5. Uracil (U)

Those are composed of a pentose (contains 5 carbon atoms) sugar (which could be a ribose or a deoxy ribose), a nitrogen-containing base (A, T, G, C, U) and a phosphate group.

P.S. You must've noticed that we name the nucleotides by the base attached to them.

Now that you know the basic structure of DNA, time to get to what DNA really is...

DNA has two polynucleotide chains running antiparallel to each other (in opposite directions) to form the double helix. They are held together by hydrogen bonds between the nitrogen containing bases that are arranged specifically.

So you would have:

Adenine with thymine with 2 hydrogen bonds and guanine with cytosine with 3 hydrogen bonds.

((P.S. Uracil, is used in RNA instead of thymine, in case you're curious))

But what really holds a polynucleotide chain together are phosphodiester bonds (covalent) to form what we call as 'sugar-phosphate backbone'.

That's briefly the structure of DNA. Now function:

DNA is composed of several genes that code for polypeptides. That's because they contain all the genetic material with which it can control the whole cell.


So genes are short lengths of DNA that code for a polypeptide chain. That includes enzymes, which catalyze ALL of our metabolic reactions. Without those enzymes, we won't survive. So DNA has got it all (the code for proteins).

What's also quiet important, is the ability to pass on all the genetic code to other cells as they divide. So what happens is, that it replicates itself semi-conservatively.

Before the cell divides, the DNA condenses and shortens to make what we call as a chromosome. A chromosome consists of two identical DNA molecules, which we call as sister chromatids, held at he center by a centromere.

Welp, hope that helped :)