Our guide picked us up and entertained us the whole way, taking us to the best spots â we even had a close encounter with a bear on the side of the road! This wildlife photo tour will explore the wildlife, geology, and natural history of Grand Teton National Park.
Chromosomes contain smaller units of genetic material called DNA. DNA is a sequence of letters that spell out the genetic code. The DNA is organized into words and sentences called genes. Humans have approximately 20,000 genes and each one influences a part of development. These genes usually come in pairs.
Today, this molecule is called DNA. Nearly all of the cells within a single organism include exactly the same DNA. DNA is a linear molecule composed of four types of smaller chemical molecules called nucleotide bases: adenine (A), cytosine (C), guanine (G), and thymine (T).The order of these bases is called the DNA sequence.n 1953, Francis Crick and James Watson described the molecular shape of DNA as a double helix.. Double-stranded DNA is composed of two linear strands that run opposite to each other, known as anti-parallel strands; these strands twist together to form a double helix.