BIOLOGY Volume 3 - General Biology Guide - 2004

APPENDICES

Appendix 3. Nomenclature and Units of Measurement

A.3.1. List of Most Frequently Used Chemical Substance Names

Old name	New name (u.c. — unchanged)
Adenine	u.c.
Adenosine	u.c.
Adipic acid	1,4-butanedicarboxylic acid
Nitric acid	u.c.
Alanine	2-aminopropanoic acid
Aliphatic	u.c.
Alkyl	u.c.
Aldehyde	u.c.
Aldol	3-hydroxybutanal
Aminobenzoic acid	u.c.
Acetaldehyde (acetic aldehyde)	Ethanal
Acetamide	Ethanamide or u.c.
Acetylene	Ethyne
Acetone	Propanone
Acetoacetic acid	3-oxobutanoic acid
Benzaldehyde	Benzoic aldehyde or u.c.
Benzoic acid	u.c.
Benzene	u.c.
n-Valeric acid	Pentanoic acid
Tartaric acid	(—) 2,3-dihydroxybutanedioic acid
Ammonium hydroxide	Aqueous ammonia solution; ammonia Water
Glycolic acid	Hydroxyethanoic acid Hydroxyacetic acid
Glyoxylic acid	Oxoethanoic acid Oxoacetic acid
Glycerol	1,2,3-trioxypropane
Glycine	Aminoethanoic acid Aminoacetic acid
Glutamic acid	2-aminoglutaric acid
Glucose	u.c.
Dextrose	(+) Glucose
Isopropyl alcohol	2-propanol, dimethylcarbinol
Indoleacetic acid	Indoleethanoic acid
Potassium permanganate	Potassium manganate
Camphor	u.c.
Carboxylic acids	u.c.
Xylene	Dimethylbenzene
Lactose	u.c.
Citric acid	2-hydroxy-1,2,3-propanetricarboxylic acid
Maleic acid	Ethylene-1,2-dicarboxylic acid
Malonic acid	Methanedicarboxylic acid
Maltose	u.c.
Butyric acid	Butanoic acid
Lactic acid	α-hydroxypropionic acid
Urea	Carbamide or u.c.
Formic aldehyde	Methanal
Oleic acid	cis-9-octadecenoic acid
Palmitic acid	Hexadecanoic acid
Pyridine	u.c.
Pyruvic acid	α-oxopropionic acid
Pyrogallol	1,2,3-trioxybenzene
Sucrose	u.c.
Ethyl alcohol	Ethanol
Methyl alcohol (wood alcohol)	Methanol
Stearic acid	Octadecanoic acid
Thiourea	Thiocarbamide or u.c.
Toluene	Methylbenzene
Acetic acid	Ethanoic acid or u.c.
Phenol	u.c.
Fructose	u.c.
Fumaric acid	trans-butenedioic acid
Quinol	1,4-dioxybenzene
Cobalt chloride	Cobalt(II) chloride
Chloroform	Trichloromethane
Carbon tetrachloride	Tetrachloromethane
Oxalic acid	Ethanedioic acid
Ethyl acetate	Ethyl ethanoate or u.c.
Ethylene	Ethene
Malic acid	Hydroxysuccinic acid
Succinic acid	Butanedioic acid

A.3.2. Abbreviations and Symbols

Adenosine 5'-pyrophosphate	ADP, or adenosine diphosphate
Adenosine 5'-triphosphate	ATP, or adenosine triphosphate
Adrenocorticotropic hormone	ACTH
Angstrom	Å; SI units are preferred: 10 Å = 1 nm
Antidiuretic hormone	ADH
Time	t
Hemoglobin	Hb
Growth Hormone	GH
Degrees Celsius	°C
Gram	g
Pressure	p
Deoxyribonucleic acid	DNA
Joule	J
Respiratory quotient	RQ
Calorie	cal; the SI unit, the joule (J), is preferred: 1 cal = 4.2 J
Calciferol	It is preferable to use "vitamin D₂", since vitamin D is a general term for a Class of compounds
Kilogram (10³ g)	kg
Coenzyme A	CoA
Luteinizing hormone	LH
Minute	min
Mole (amount of substance unit)	The mole replaces such terms as gram-molecule, gram-ion, gram-atom, etc.
Molar (concentration)	M (mol/l)
Normal solution	The term "isoosmotic solution" should not be used
Newton	N
Negative logarithm of hydrogen ion concentration	pH
Petroleum ether	The term "light gasoline" should not be used
Approximately equal to	=
Ribonucleic acid	RNA
CEREBROSPINAL FLUID	CSF
Mean value of x
Standard deviation (hypothetical population)	s
Standard deviation (observed sample)	S
Sum (statistical term)	Σ
Temperature	T (absolute) t (other scales)
Thyroid-stimulating hormone	TSH
Chi-square	χ²
Central Nervous system	CNS
Krebs cycle	Tricarboxylic Acid Cycle
Parts per million	ppm
Number of observations	n (or f)
Endoplasmic reticulum	ER

A.3.3. International System of Units (SI)

A.3.3.1. Names and Symbols of Base SI Units

Physical quantity	Name	Symbol
Time	second	s
Length	meter	m
Amount of substance	mole	mol
Mass	kilogram	kg
Luminous intensity	candela	cd
Electric current	ampere	A
Solid angle	steradian	sr
Thermodynamic temperature	kelvin	K

A.3.3.2. Derived SI Units with Special Names

Quantity	Unit	Symbol	Expression in SI units
Electric charge	coulomb	C	A · s
Power	watt	W	kg · m² · s^-3 = J · s^-1
Volume	cubic meter		m³
Illuminance	lux	lx	cd · sr · m^-2 or lm · m^-2
Density	kilogram per cubic meter		kg · m^-3
Area	square meter		m²
Work, energy, quantity of heat	joule	J	kg · m² · s^-2; 1 J = 1 N · m
Luminous flux	lumen	lm	cd · sr
Force	newton	N	kg · m · s^-2 = J · m^-1
Electric potential	volt	V	kg · m² · s^-3 · A^-1; W / A

A.3.3.3. Special Units Temporarily Accepted for Use

Quantity	Unit name	Symbol	Conversion to SI units
Length	angstrom	Å	10^-10 m = 0.1 nm
Length	micron	µm	10^-6 m = 10^-3 mm = 1 µm
Volume	liter	l	10^-3 m³ = 1 dm³
Mass	tonne	t	10³ kg = Mg
Pressure	millimeter of mercury	mmHg	10² mmHg ≈ 13.3 kPa

A.3.3.4. Prefixes and Multipliers for SI Submultiples and Multiples

Used to indicate decimal fractions and multiples of base and derived SI units.

Multiplier	Prefix	Symbol
0.000 000 000 001 = 10^-12	pico	p
0.000 000 001 = 10^-9	nano	n
0.000 001 = 10^-6	micro	µ
0.001 = 10^-3	milli	m
1000 = 10³	kilo	k
1 000 000 = 10⁶	mega	M
1 000 000 000 = 10⁹	giga	G
1 000 000 000 000 = 10¹²	tera	T

Therefore, 1 nanometer (nm) = 1 · 10^-9 m, and 1 centimeter (cm) = 1 · 10^-2 m.

Note that the kilogram is somewhat inconsistent with the other prefixes in the table above, as it is a base SI unit. When working in a teaching laboratory, it is most convenient to use units such as the gram (g) and the cubic centimeter (cm³). Whenever possible, base SI units should be used.

A.3.3.5. Rules for Writing SI Units

1. Unit symbols are not abbreviations of the full name, and therefore no period is placed after them, except when the symbol appears at the end of a sentence.

2. Symbols do not take a plural form.

3. Symbols are generally written in lowercase letters, except when the unit is named after a famous scientist, for example, N (Newton), W (Watt), or J (Joule).

4. Symbols combined into a single expression may be written, for example, as meters per second or m · s^-1.

Last update: 06/08/2026

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