A 2.3x
10 -3
B 1.8x
10 - 5
C 5.0x
10 4
D 4.6x
10 4
E 2.0x
10 7
F 2.0x
10 -2
SCIENTIC NOTATION -METRIC SYSTEM
Scientists,clinicians
and most countries utilize the metric system as a standardizingsystem for
measuring the physical and biological world around them. The metricsystem is
based upon powers of ten where units of measurement increase ordecrease by
tens, hundreds or thousands, etc. The standard unit of length isthe meter, mass
(weight) the gram and volume the liter. Various prefixes areused with the
metric system to represent units of measurement larger or smallerthan the
standard unit and are applicable to length, mass and volume. The mostcommon
prefix for values larger than the standard unit is kilo- whichrepresents a
thousand standard units. The more common prefixes used in biologywhich
represent fractions of the standard unit are deci-, centi-, milli-,micro-, and
nano-. See Table 1-3. There are one thousand nano- units in amicro- unit and
one thousand micro- units in a milli- unit. One thousand milli-units are in the
standard unit of measurement. Thus 1000 times 1000 equals onemillion nano-
units for each milli- unit. There are also one billion nano-units per standard
unit, 1000 times 1000 times 1000.
Table 1.3. Metric System prefixes.
|
Prefix |
Symbol |
Value Compared to the Standard
Unit |
|
kilo |
k |
1.0 x 10 3 |
|
deci |
d |
1.0 x 10 -1 |
|
centi |
c |
1.0 x 10 -2 |
|
milli |
m |
1.0 x 10 -3 |
|
micro |
µ (mu) |
1.0 x 10 -6 |
|
nano |
n |
1.0 x 10 -9 |
LENGTH
Thestandard
unit of length is the meter (m) and is equivalent to 39.37 inches orjust over
one yard. The common metric lengths used in biology include thecentimeter (one
hundredth of a meter), the millimeter (one thousandth of ameter) and the
micrometer (one millionth of a meter). Most cells range from 50to 200
micrometers in diameter.
See Figure 1-1.
Figure 1-1. Length relationships
frommeters to micrometers.
MASS OR WEIGHT
Thestandard
unit of mass is the gram (the amount of artificial sweetener in thesugar
packages found in family restaurants). The common weights seen in biologyrange
from large kilogram organisms to small nanograms of chemicals, which arelocated
within the body's fluid. See Figure 1-2.
one gram = 1,000
mg = 1,000,000 µg = 1,000,000,000 ng
Figure 1-2. Mass Relationships
fromGrams to Nanograms.
VOLUME
|
|
Thestandard
unit of volume is the liter and is equivalent to 1.06 quarts. Volumein the
metric system can be expressed in liters or in cubic measurements oflength. The
common units used in physiology are the milliliter (one thousandthof a liter)
and the microliter (one millionth of a liter). One milliliter isalso equal to a
cubic centimeter (cc or cm3) and a microliter is equivalent
to acubic millimeter (mm3).Figure 1-3.
Figure 1-3. Liter Diagram.
Reviewthe material in Table 1-3, Figure 1-1, Figure 1-2, and Figure 1-3 and calculatethe following conversions.
1.
How
manymilliliters are in one liter?
2.
How
manymicroliters are in one milliliter?
3.
How
manymicroliters are in 35 liters
4.
How
manygrams are in 2.2 kilograms?
5.
How
manymilligrams in 54,000 micrograms?
6.
How
manymillimeters are in 25 centimeters?
7.
How
manymilliliters are in 420 cubic centimeters (cc)?
DATA ANALYSIS
Thedata
obtained from scientific research or laboratory exercises can beinterpreted
when presented in a table, graph or chart. Tabular values areusually presented
in tables as raw data or treated data.
Define the following terms used
in theanalysis of data:
Average or mean
Mode
Range
Graphicalrepresentation
of the data allows for a quick pictorial analysis of theinformation. A graph
usually has two variables observed in the experiment withone plotted along the
horizontal x-axis and the other variable along thevertical y-axis. The
relationship between the variables of a graph can linearor curvilinear and show
a positive or direct relationship, a negative orinverse relationship, a neutral
relationship where the dependent variable isconstant or some other
relationship. See Figure 1-4.
A B C D E
Figure 1-4. Relationships
between thevariables of a graph.
Graphs A, B and C are linear
graphs witha graph A having a positive or direct relationship, graph B a
negative orinverse relationship and graph C as being constant. Graph D shows a
positivecurvilinear relationship and E a negative curvilinear relationship.
Theindependent
variable is changed, usually at regular intervals, in order toobserve its
effect on the dependent variable. Most graphs plot the independentvariable on
the abscissa (horizontal x-axis) and the dependent variable on theordinate
(vertical y-axis). Graphs can be line, histograms or scatter. SeeFigures 1-5
and 1-6.
Agraph
is first constructed by differentiating between the dependent andindependent
variables, and their axes. The spacing of the tabular data on theaxes is
important. This is achieved by spreading the values out along the axesand by
using the same distances for equivalent values. The first datum point isthen
ready for plotting on the graph. The values for both variables are locatedon
their respective axes. Each value is then moved either vertically
orhorizontally until both of them intersect for the datum point. This process
isthen continued for all values. Finally all the data points on the graph
areconnected point to point with straight lines.
Table 1-4. Age and Weight in Boys.
|
Age (years) |
Weight (kilograms) |
Age (years) |
Weight (kilograms) |
|
0 |
3.4 |
10 |
32.6 |
|
1 |
10.1 |
11 |
35.2 |
|
2 |
12.6 |
12 |
38.3 |
|
3 |
14.6 |
13 |
42.2 |
|
4 |
16.5 |
14 |
48.8 |
|
5 |
18.9 |
15 |
54.5 |
|
6 |
21.9 |
16 |
58.8 |
|
7 |
24.5 |
17 |
61.8 |
|
8 |
27.3 |
18 |
63.1 |
|
9 |
29.9 |
|
|
Whichfactor
on Table 1-4 is the independent variable?
Whichaxis
of a graph is the independent variable usually plotted on?
What
is therelationship between age and body weight as seen in Figure 1-5 and
Figure 1-6.
Whatare
the two age ranges in Figures 1-5 and 1-6 that show a dramatic increase inbody
weight?
Figure 1-5. Line Graph of the
BodyWeight Data.
Figure 1-6. Bar Chart of the
BodyWeight Data.
Datacan
also be visualized in a chart such as a bar chart or pie diagram. A piechart is
a circular diagram that is divided into sections that represent acategory of
data. The total area or all of the data is usually expressed as 100percent. See
Figure 1.7.
Figure1-7.
Age Distribution at Mesa College.
GRAPHING DATA
OXYGENAND HEMOGLOBIN
Table 1-5. Relationship Between
OxygenLevels and Percent Saturation.
|
Partial
Pressure (Concentration) of O2 (mmHg) |
10 |
20 |
30 |
40 |
50 |
60 |
70 |
80 |
90 |
100 |
|
Percent O2 Saturation
on Hemoglobin |
14 |
35 |
60 |
75 |
84 |
89 |
92 |
95 |
96 |
97 |
What is the independent variable on Table1-5?
What
is thespecific variable from Table 1-5 is plotted on the vertical axis?
Label both axes
correctly on Figure1-8 and plot the data from Table 1-5 on Figure 1-8. Draw a
line connectingdatum point to datum point.
Figure 1-8. Hemoglobin
Saturationverses Oxygen Levels.
Describe
therelationship between the partial pressure of oxygen gas to the percent
ofoxygen saturation on hemoglobin.
ROD CELLS
Table 1-6. Rod Cell Sensitivity
toDifferent Wavelengths.
|
Color |
violet |
blue |
green |
yellow |
orange |
red |
|
Wavelength (nanometers) |
400 |
425 |
450 |
475 |
500 |
525 |
550 |
575 |
600 |
625 |
650 |
|
Rod Cell Sensitivity |
20 |
30 |
60 |
90 |
100 |
85 |
40 |
15 |
5 |
0 |
0 |
Plotthe
data from Table 1-6 on Figure 1-9 and draw a line connecting the datapoints.