What is the difference between DNA and genes?

Answer 1

The following earlier provided answer, I believe, is wrong:

"A gene is not a single structure or thing. It is made up of the micro-structures that determine a trait. These micro-structures are primarily chromosomes. Chromosomes are pieces of DNA. A single strand of DNA stretched out would be about 3 feet long. A common analogy is that DNA is like the strands of a necklace and the chromosomes are the beads. There are two strands of DNA that intertwine forming a pattern called the "Double Helix"

basically, a gene is part of a chromosome. which all falls underneath DNA"

To my understanding, a chromosome consists of a single DNA string (up to 2 meters long if unfolded) that is tightly curled up around many protein molecules (histone) and around itself (much like old telephone wires after years of use). The resulting bundle is called a chromosome.

A Gene is a particular section of the chromosome's DNA string. There are many such sections on the DNA string - thus it contains (also calls 'codes') many genes - in humans between 500 and 4500 depending on what chromosome. One gene contains information for producing one particular protein. It is the sequence of bases (T, C, G or A) in the DNA gene section that defines which protein.

The beginning and end of a gene section is marked by a start and a stop sequence ( also called codons) of a gene. In DNA the start can typically be the base sequence ATG and the stop sequence typically TAA, TGA or TAG.

Humans have 23 pairs of chromosomes. Each chromosome has a different DNA string. Thus some times you see people wrinting that a chromosome is only a part of a person's DNA. By that, they mean all the DNA in the body - whcih of course is true, since you have 23 different pairs of chromosomes. But that should not be misunderstood as "a chromosome is part of a DNA string" as frequently seen on the net.
Genes are to be found on Chromosomes.

And Chromosomes are singular pieces of DNA, which contain many genes, regulatory elements and other nucleotide sequences.

Answer 2

A gene is a section of DNA that will eventually code for a specific protein. All genes are composed of DNA but not all DNA are genes.

or

It is a name given to some stretches of DNA and RNA that code for a polypeptide.

or

A gene is a segment of DNA that will transcript for a specific protein.