Mathematical skills in Life Sciences
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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.
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Measure the length of the scale line on the micrograph in mm, e.g. 1 µm = 17mm
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Measure the diameter of the organelle in millimetres, e.g. = 60mm
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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:
Sum =1 602 cmAverage:
Average =160210=160,2 cmAnswer: 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 (%):
Percentage =Number with feature (A)Total number (B)×100Example: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:
=AB×100=448×100=8,3%Answer: 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:
=100−8,3=91,7%Answer: 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 | 1 | 1 000 | 1 000 000 | 1 000 000 000 |
mm | 10−3 or 1/1 000 | 1 | 1 000 | 1 000 000 |
µm (micrometres) | 10−6 or 11 000 000 | 10−3 or 11 000 | 1 | 1 000 |
nm (nanometres) | 10−9 or 11 000 000 000 | 10−6 or 1/1 000 000 | 10−3 or 11 000 | 1 |
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