Maths in A-level Biology

• Draw a Tangent to where it meets the x-axis and Y-axis
• calculate the gradient - change in Y / Change in X
• Enzymes lower the activation energy of a reaction

• using a scale bar to work out magnification - measure the length of the scale bar, convert to units used on the scale bar then divide by the number on the scale bar

• Pipette a drop of water onto the slide, then use tweezers to place a thin section of your specimen ontop of the water drop
• Add a drop of staine e.g. eosin for cytoplasm & iodine for starch
• Finally add a cover slip and don't get any air bubbles

• Line up the eyepiece graticule and stage micrometer
• Each division on the stage micrometer will be shown
• You can then see how many eye piece gracticle unit is 1 stage micrometer then divide these by each other
• You then know how many unit it is equal too

Calulate Mitotic Index by counting number of cells undergoing mitosis (pmat)/total number of cells x 100

This starts with an inital sucrose standard of 2M diluting by a factor of 2

• Line up five test tubes
• Add 10cm3 of the inital 2M sucrose standard to the first test tube and add 5cm3 of distilled water to the other test tubes
• Using a pipette, draw 5cm3 of the solution from the first test tube add it to the distilled water in the second and mix- you have 10cm that is half as concentrated solution than the first
• Repeat three more times to create solutions of 0.5M, 0.25M and 0.125M  

Index of diversity = D= N(N-1)/sum of n(n-1)

• calulate N = (number of species)
• calculate N(N-1)
• calculate n(n-1) n= number in an individual species
• caluculate the sum of n(n-1)
• divide through N(N-1)/sum of n(n-1) 

Mark Release Recapture = N = MC/R

N= size of population 

M = number in first sample marked 

C= number in second sample 

R= number of marked in second sample

Net Primary production = gross primary production - repiratory losses

net production = chemical energy ingested (i) - (chemical energy lossed in waste x energy lost in respiration)

10% energy transferred to each trophic level 

Cardiac Output = Heart rate x Stroke Volume

Cardiac Outut - the amount of blood pumped through the circulatory system in one minute

Heart Rate - Number of heart beats in a minute

Stroke Volume - the amount of blood pumped by the left ventricle of the heart in one contraction of the heart