Deoxyribonucleic acid and ribonucleic acid are two chemical substances.
in transmitting genetic information from parent to offspring. It was.
known early into the.
20th century that chromosomes, the genetic material of cells, contained.
DNA. In 1944,.
Oswald T. Avery, Colin M. MacLeod, and Maclyn McCarty concluded that DNA.
was the.
basic genetic component of chromosomes. Later, RNA would be proven to.
regulate.
protein synthesis. (Miller, 139).
DNA is the genetic material found in most viruses and in all.
cellular organisms. .
Some viruses do not have DNA, but contain RNA instead. Depending on the.
organism,.
most DNA is found within a single chromosome like bacteria, or in several.
chromosomes.
like most other living things. (Heath, 110) DNA can also be found.
outside of.
chromosomes. It can be found in cell organelles such as plasmids in.
bacteria, also in.
chloroplasts in plants, and mitochondria in plants and animals.
All DNA molecules contain a set of linked units called.
nucleotides. Each.
nucleotide is composed of three things. The first is a sugar called.
deoxyribose. Attached.
to one end of the sugar is a phosphate group, and at the other is one of.
several.
nitrogenous bases. DNA contains four nitrogenous bases. The first two,.
adenine and.
guanine, are double-ringed purine compounds. The others, cytosine and.
thymine, are.
single-ringed pyrimidine compounds. (Miller, 141) Four types of DNA.
nucleotides can.
be formed, depending on which nitrogenous base is involved.
The phosphate group of each nucleotide bonds with a carbon from.
the.
deoxyribose. This forms what is called a polynucleotide chain. James D.
Watson and.
Francis Crick proved that most DNA consists of two polynucleotide chains.
that are.
twisted together into a coil, forming a double helix. Watson and Crick.
also discovered.
that in a double helix, the pairing between bases of the two chains is.
highly specific. .
Adenine is always linked to thymine by two hydrogen bonds, and guanine is.
