
a Quick reference
A Dictionary of Ecology (5 ed.)
The usual abbreviation for *year (from the Latin annus, meaning year).

a Reference library
Oxford Dictionary of Biochemistry and Molecular Biology (2 ed.)
1 abbr. for adsorbed.
2 symbol for atto+ (SI prefix denoting 10−18).
3 axial.
4 year.

2′‐5′A Reference library
Oxford Dictionary of Biochemistry and Molecular Biology (2 ed.)
symbol for any member of a series of oligonucleotides of the general formula p a A[2′p5′A] n , where p

Å Reference library
Oxford Dictionary of Biochemistry and Molecular Biology (2 ed.)
symbol for ångström (unit of length equal to 10−10 m).

a Reference library
Oxford Dictionary of Biochemistry and Molecular Biology (2 ed.)

A Reference library
Oxford Dictionary of Biochemistry and Molecular Biology (2 ed.)
symbol for
1 acid‐catalysed (of a reaction mechanism).
2 a residue of the α‐amino acid

A Reference library
Oxford Dictionary of Biochemistry and Molecular Biology (2 ed.)
symbol for
1 absorbance.
2 activity (def. 2).
3 affinity.
4 Helmholtz function.
5 mass number/nucleon number.

A Quick reference
A Dictionary of Genetics (8 ed.)
1. mass number of an atom.
2. haploid set of autosomes.
3. ampere.
4. adenine or adenosine.

(A + T)/(G + C) ratio Reference library
Oxford Dictionary of Biochemistry and Molecular Biology (2 ed.)
the ratio of the sum of the adenine plus thymine bases to the sum of the guanine plus cytosine bases