What is the difference between a nucleotide, gene, and a chromosome?

Expert Answers

An illustration of the letter 'A' in a speech bubbles

A nucleotide is a building block to DNA. The DNA contains genes, which are located on individual chromosomes. They are related, and you can't really have DNA without genes and for sure not without nucleotides.

A nucleotide is made of three basic pieces.  A phosphate, a five carbon sugar (deoxyribose),...

Unlock
This Answer Now

Start your 48-hour free trial to unlock this answer and thousands more. Enjoy eNotes ad-free and cancel anytime.

Start your 48-Hour Free Trial

A nucleotide is a building block to DNA. The DNA contains genes, which are located on individual chromosomes. They are related, and you can't really have DNA without genes and for sure not without nucleotides.

A nucleotide is made of three basic pieces.  A phosphate, a five carbon sugar (deoxyribose), and one of four nitrogen bases. The phosphate and sugar stack on top of each other and the base sticks off the side of the sugar. It resembles the shape of an "L." That's a nucleotide. Another corresponding base would attach to the base and then be connected to the sugar with the phosphate on top. Now it should look like a "U" with a flat bottom. That's two nucleotides attached side by side. Stick another nucleotide pair beneath it and another and another and it starts looking like a ladder. Twist that ladder, and you have the double helix that is DNA.

If you made that DNA ladder 3 billion ladder "rungs" long, you would have a human DNA sequence. Divide that up into 46 chunks, and those are the chromosomes present in the human genome.  In other words a chromosome is a really long section of DNA, which is made of nucleotide units.

A gene is a smaller section of a chromosome. A different way to put it is that a gene is a smaller section of DNA, or a group of bases (which are a part of the nucleotide).

Approved by eNotes Editorial Team