Mathematical skills in Life Sciences
Previous
Presenting data
|
Next
Lab safety procedures
|
Mathematical skills in Life Sciences (ESG3T)
Mathematical skills are important in Life Sciences. Below are explanations of some of the skills you will encounter.
- Scales
- Averages
- Percentages
- Conversions
NB. You must state the UNITS at the end of each calculation, e.g. cm, degrees, kg, etc.
Scales (ESG3V)
A scale is given in a diagram, drawing or electron micrograph so that the actual size of the object that is being shown can be determined. The object could be bigger or smaller in real life.
Example: To measure the diameter of a chloroplast with a scale line of 1 µm.
-
Measure the length of the scale line on the micrograph in mm, e.g. 1 µm = 17mm
-
Measure the diameter of the organelle in millimetres, e.g. = 60mm
-
True diameter of chloroplast:
Answer: The true diameter of the chloroplast is 3.53 μm.
Averages (ESG3W)
To find an average of a set of numbers, you add all the items and divide the total by the number of items.
Example: Find the average height in a class of 10 learners with the following heights in cm: 173, 135, 142, 167, 189, 140, 139, 164, 172, 181 cm.
- Add all 10 learners heights together to get a total.
- Divide the total by the number of learners (10) to get the average.
Total:
\begin{align*} \text{Sum } &= \text{1 602}\text{ cm} \end{align*}Average:
\begin{align*} \text{Average } &= \frac{1602}{10} \\ &= \text{160,2}\text{ cm} \end{align*}Answer: The average height of the learners is 160,2 cm
Percentages (ESG3X)
To calculate a percentage, multiply the fraction by 100.
Formula for calculating percentage (\(\%\)):
\[\text{Percentage } = \frac{\text{Number with feature }(A)}{\text{Total number }(B)} \times 100\]Example:There are 48 learners and 4 of them are left handed. Calculate the percentage of learners in your class that are left-handed.
- Count how many learners are left handed (A).
- Count the total number of learners in the class (B).
- Divide the number of left-handed learners (A) by the total number of learners (B) to get a fraction or proportion.
- Multiply the fraction by 100.
Therefore, to calculate the percentage of learners that are left-handed:
\begin{align*} &= \frac{A}{B} \times 100 \\ &= \frac{4}{48} \times 100 \\ &= \text{8,3}\% \end{align*}Answer: \(\text{8,3}\%\) of the learners in your class are left-handed.
Example: Using the same class of learners, calculate the percentage of learners that are right-handed.
To calculate the percentage of the class that is right handed, one could count the number of right-handed students, and perform the percentage calculation again. Or, since the whole class is equal to 100 %, one can simply subtract the percentage of left-handed students and you will be left with the percentage of right-handed students.
The percentage of right-handed learners:
\begin{align*} &= 100 - \text{8,3} \\ &= \text{91,7}\% \end{align*}Answer: \(\text{91,7}\%\) of the learners in your class are right-handed.
Conversions (ESG3Y)
Below is a table with some common conversions that you will need to use in the study of Life Sciences:
From unit: | To unit (number of these units per “From unit”): | |||
m | mm | µm | nm | |
m | \(\text{1}\) | \(\text{1 000}\) | \(\text{1 000 000}\) | \(\text{1 000 000 000}\) |
mm | \(\text{10}^{-\text{3}}\) or 1/\(\text{1 000}\) | \(\text{1}\) | \(\text{1 000}\) | \(\text{1 000 000}\) |
µm (micrometres) | \(\text{10}^{-\text{6}}\) or \(\frac{1}{\text{1 000 000}}\) | \(\text{10}^{-\text{3}}\) or \(\frac{1}{\text{1 000}}\) | \(\text{1}\) | \(\text{1 000}\) |
nm (nanometres) | \(\text{10}^{-\text{9}}\) or \(\frac{1}{\text{1 000 000 000}}\) | \(\text{10}^{-\text{6}}\) or 1/\(\text{1 000 000}\) | \(\text{10}^{-\text{3}}\) or \(\frac{1}{\text{1 000}}\) | \(\text{1}\) |
Previous
Presenting data
|
Table of Contents |
Next
Lab safety procedures
|