Video Transcript
Which of the following best
describes a gene? (A) A section of DNA or RNA that
codes for a particular protein or molecule. (B) A section of DNA or RNA that
codes for a specific carbohydrate. (C) All of the DNA and RNA within
an organism. (D) The physical appearance of an
organism. (E) The combination of different
alleles that make up an organism.
Our genetic information is stored
in our cells as DNA. We have a lot of DNA in a single
cell. And if we were to unravel it and
stretch it out, it would be about two meters in length. This isn’t one long, continuous
molecule of DNA. Instead, it’s organized into
structures called chromosomes. In humans, we have 23 pairs of
chromosomes, or 46 in total. Let’s look more closely at one of
these chromosomes so we can answer our question.
DNA is wrapped around special
proteins called histones that are tightly packed up into the chromosome structure we
see above. This is how we can package two
meters of DNA inside a single cell.
Scattered throughout our DNA are
sections of DNA called genes. Genes provide the instructions to
produce different functional units. For example, a gene can code for a
protein like insulin, or it can produce an RNA molecule with a specific
function. These can include a structural RNA
molecule like ribosomal, or rRNA that is a component of the ribosome or a regulatory
RNA molecule like a microRNA that can regulate the expression of different
genes.
Going back to our question, the
option that best describes a gene is given by answer choice (A): a section of DNA or
RNA that codes for a particular protein or molecule.
