More pages in this category (in alphabetical order):
Cysteine
Amino Acids
Amino acids are important biological units that are sometimes called the "building
blocks" of proteins because many amino
acids together form proteins. Proteins form a significant proportion of
the structure
of cells, cells being
the basic functional units of living organisms.
Chemistry of Amino Acids
Amino acids are organic compounds that include both an amino group, and a carboxyl group.
The term "organic
compound"
refers to substances whose molecular structure is based on the
presence and properties of the element carbon, whose chemical symbol is C.
An "amino group" is
a group of atoms arranged in a particular configuration that
includes the elements nitrogen and hydrogen and is represented by
-NH2.
A "carboxyl group" is
a group of atoms arranged in a particular configuration that
includes carbon, oxygen, and hydrogen and is represented by -COOH.
Cysteine is an amino acid.
The molecular formula of cysteine is C3H7NO2S
Amino acids generally are explained further in the column on the rightin further detail below. Briefly, there are two types of amino acid:
- Those that can be synthesized by the body itself (non-essential amino acids), and
- those that, although necessary for the healthy growth or maintenance of the body, cannot be produced by the body itself.
This second type of amino acids are called essential amino acids, and are also referred to as indispensible amino acids in some textbooks.
Cysteine is a "non-essential" or "dispensible" amino
acid because, although its presence in an appropriate quantity is important
for good health, the human body can produce this chemical from an excess
of certain other amino acids in the body. Therefore it is not essential as a part of the diet.
Cysteine is sometimes described
as a "natural sulphur antibiotic", which can be explained by its
sulphur content - as indicated in its chemical formula.
The presence of this sulphur component is responsible for some of the
main functions of cysteine. For example, the disulphide
(S-S) links between adjacent molecules in the polypeptide chains formed
by cysteine help
to form the 3-dimensional structures of the proteins of which they are
part.
Cysteine is also an important part of many enzymes.
Amino Acids
Amino acids are important biological units that are sometimes called the "building
blocks" of proteins because many amino
acids together form proteins. Proteins form a significant proportion of
the structure
of cells, cells being
the basic functional units of living organisms.
Chemistry of Amino Acids
Amino acids are organic compounds that include both an amino group, and a carboxyl group.
The term "organic
compound"
refers to substances whose molecular structure is based on the
presence and properties of the element carbon, whose chemical symbol is C.
An "amino group" is
a group of atoms arranged in a particular configuration that
includes the elements nitrogen and hydrogen and is represented by
-NH2.
A "carboxyl group" is
a group of atoms arranged in a particular configuration that
includes carbon, oxygen, and hydrogen and is represented by -COOH.
For further information about amino acids in general, see Amino Acids.
