Genes vs. DNA vs. Chromosomes – Instant Egghead #19


You can think about DNA,
genes and chromosomes as forming a kind of blueprint of life. These are the plans that tell the body
how to make things. In this case proteins, which are
the body’s basic building blocks. But, unlike a blueprint for a house where all the information is stored
on a flat piece of paper, the blueprint of life has many levels
of organization to it. Let’s start with DNA the most basic level. A DNA molecule is made up
of a sugar backbone and four flavors of a molecule
called a nucleotide. These nucleotides are arranged
along the backbone in a unique order. When your body needs a particular protein, it reads the sequence of nucleotides. and uses it as a template
to make that protein. Moving up a level of organization,
we have genes. Genes are long snippets or chunks of DNA. They’re also the most basic units
of inheritance. Traits are passed on
from parents to children in the form of genes. Genes include other information
about building proteins. For example, they tell the body
how long a protein should be and how much to make and when to make it. Genes also have directions about
where DNA can be edited out to make proteins with different functions. This is how the body makes
an estimated one million proteins from only twenty thousand genes. The next level up is the chromosome. Humans have 46 of these, arranged in pairs. Chromosomes are long strands of DNA wrapped around BEACH bobbin proteins
called Histones. Chromosomes contain many genes
along with long stretches of DNA whose purpose we’ve yet to figure out. In order to make a protein,
DNA has to be unwound from its histones. This is controlled by a process
called acetylation and it’s just another level of control
the body has over the production of proteins. So, as you can see, the blueprint
for our bodies is quite well organized if only that was the case,
for the rest of our lives. For Scientific Americans,
Instant Egghead, I’m Eric Olson.