Chemistry Reference
In-Depth Information
TABLE 85
Nucleic Acids
Abbreviation
Full name
Characteristic function
DNA
Deoxyribonucleic acid
Carries genetic instructions for making
living organisms
n-DNA
Nuclear
DNA enclosed within the chromosomes, in
deoxyribonucleic acid
the nucleus of the cell; inherited from
both parents
mt-DNA
Mitochondrial
DNA in cell mitochondria; inherited only
deoxyribonucleic acid
from the mother
RNA
Ribonucleic acid
Transfers genetic information from DNA to
proteins synthesized by the cell
m-RNA
Messenger ribonucleic
Transfers genetic information from nuclear
acid
DNA to the protein synthesized in cell
ribosomes
r-RNA
Ribosomal ribonucleic acid
A stable, structure component of ribosomes
t-RNA
Transfer ribonucleic
Picks up specific amino acids and transfers
acid
them to the appropriate location in
m-RNA during protein synthesis
TEXTBOX
64
THE NUCLEIC ACIDS: DNA AND RNA
The
nucleic
acids,
deoxyribonucleic acid
(DNA) and
ribonucleic acid
(RNA),
which carry embedded in their complex molecules the genetic information
that characterizes every organism, are found in virtually all living cells. Their
molecules are very large and complex biopolymers made up basically of
monomeric units known as
nucleotides
. Thus DNA and RNA are said to be
polynucleotides
. The nucleotides are made up of three bonded (linked) com-
ponents: a
sugar
, a
nitrogenous base
, and one or more
phosphate groups
:
•
The nature of the
sugar
varies, depending on whether the polynu-
cleotide is RNA or DNA; in RNA the sugar is
ribose
(C
5
H
10
O
5
) while in
DNA it is
deoxyribose
(C
5
H
10
O
4
). The prefix
deoxy
-, often found in
relation to nucleic acids, means “without oxygen”; thus
deoxyribose
denotes ribose lacking (some) oxygen.
•
Four different nitrogenous bases may occur in each nucleotide:
adenine
(A),
cytosine
(C),
guanine
(G), and
thymine
(T); in DNA,
uracyl
(U), substitutes for the thymine in RNA.
•
The
phosphate groups
are electrically charged atomic groups com-
posed of phosphorus and oxygen atoms (the formula of the phos-
phate group is PO
3
−
). The large amount of phosphorus in the nucleic
acids, it should be mentioned, is another unusual characteristic of
the nucleic acids among biological materials.
