CONCEPTS IN BIOLOGY

Appendix 1

The Metric System

Standard Metric Units

Abbreviation

Standard unit of mass

gram

g

Standard unit of length

meter

m

Standard unit of volume

liter

L

Common Prefixes

Examples

kilo

1,000

A kilogram is 1,000 grams

centi

0.01

A centimeter is 0.01 meter.

milli

0.001

A milliliter is 0.001 liter.

micro (μ)

one-millionth

A micrometer is 0.000001 (one-millionth) of a meter.

nano (n)

one-billionth

A nanogram is 10-9 (one-billionth) of a gram.

pico (p)

one-trillionth

A picogram is 10-12 (one-trillionth) of a gram.

Units of Length

Unit

Abbreviation

Equivalent

meter

m

approximately 39 in.

centimeter

cm

10-2 m

millimeter

mm

10-3 m

micrometer

μm

10-6 m

nanometer

nm

10-9 m

angstrom

A

10-10 m

Length Conversions

1 in. = 2.5 cm

1 ft = 30 cm

1 yd = 0.9 m

1 mi = 1.6 km

1 mm = 0.039 in

1 cm = 0.39 in

1 m = 39 in

1 m = 1.094 yd

1 km = 0.6 mi

To Convert

Multiply By

To Obtain

inches

2.54

centimeters

feet

30

centimeters

centimeters

0.39

inches

millimeters

0.039

inches

Units of Volume

Unit

Abbreviation

Equivalent

liter

L

approximately 1.06 qt

milliliter

mL

10-3 L (1 mL = 1 cm3 = 1 cc)

microliter

μL

10-6 L

Volume Conversions

1 tsp = 5 mL

1 tbsp = 15 mL

1 fl oz = 30 mL

1 cup = 0.24 L

1 pt = 0.47 L

1 qt = 0.95 L

1 gal = 3.8 L

1 mL = 0.03 fl oz

1 L = 2.1 pt

1 L = 1.06 qt

1 L = 0.26 gal

To Convert

Multiply By

To Obtain

fluid ounces

30

milliliters

quarts

0.95

liters

milliliters

0.03

fluid ounces

liters

1.06

quarts

Units of Weight

Unit

Abbreviation

Equivalent

kilogram

kg

103 g (approximately 2.2 lb)

gram

g

approximately 0.035 oz

milligram

mg

10-3 g

microgram

μg

10-6 g

nanogram

ng

10-9 g

pictogram

pg

10-12 g

Weight Conversions

1 oz = 28.3 g

1 lb = 453.6 g

1 lb = 0.45 kg

1 g = 0.035 oz

1 kg = 2.2 lb

To Convert

Multiply By

To Obtain

ounces

28.3

grams

pounds

453.6

grams

pounds

0.45

kilograms

grams

0.035

ounces

kilograms

2.2

pounds

Temperature

Apothecary System of Weight and Volume*

Metric

Apothecary

Metric

Apothecary

Weight

Weight

Volume

Volume

30 g

= 1 ounce

1,000 mL

= 1 quart

15 g

= 4 drams

500 mL

= 1 pint

10 g

= 2.5 drams

250 mL

= 8 fl ounces

4 g

= 60 grains

90 mL

= 3 fl ounces

(= 1 dram)

30 mL

= 1 fl ounce

2 g

= 30 grains

1 g

= 15 grains

___________________________

*Used by pharmacists in preparing medications.

Temperature Conversions

Some Equivalents

0°C = 32°F

37°C = 98.6°F

100°C = 212°F