2 2.1.4 comparing the relative sizes of molecules……………….. You have 3 minutes to answer the following: Give two reasons why we use light microscopes and give the main reason why we use the electron microscope.
3 What units of measurement do we use in biology? International System. Why?So that the same units are used in every country in the world.Copy the following information.
4 SI units (international system) 1 metre (m) = 1m1 millimeter (mm) = 1mm = 1x10-3m1 micrometre (μm) = 1μm = 1x10-6m1 nanometre (nm) = 1nm = 1x10-9m1 centimetre cubed = 1cm31 decimetre cubed = 1dm3 (deci = 1/10 of a metre = 10 cm)1 second = 1s1 minute = 1min1 hour = 1hConcentration is measured in mol dm-3This just means mols per decimetre cubed.
5 Activity In pairs: Consider the following structures: Put them in order of size starting with the smallest.a hydrogen molecule.a human cheek cell.a cell organelle(mitochondrion).a virus.a bacterium.plasma membrane
6 Answers a hydrogen molecule. plasma membrane a virus. a bacterium. a cell organelle(mitochondrion).a human cheek cell.See page 10 of your text book.