Surface Area to Volume Ratio For cells to survive, metabolic reactions must be occurring, these reactions depend on: Materials constantly being exchanged across the plasma membrane The volume/mass ...
Functions of Life Unicellular (single-celled) and multicellular (many cells) organisms must carry out the following functions to stay alive: Metabolism - all the enzyme-catalysed reactions occurrin...
Cell Theory Until microscopes became powerful enough to view individual cells, no-one knew for certain what living organisms were made from A scientist called Robert Hooke came up with the term "ce...
Measuring Half-Life Half-life is defined as: The time taken for the initial number of nuclei to halve for a particular isotope This means when a time equal to the half-life has passed, the activity...
The Law of Radioactive Decay Since radioactive decay is spontaneous and random, it is useful to consider the average number of nuclei which are expected to decay per unit of time This is known as t...
The Neutrino An electron neutrino is a type of subatomic particle with no charge and negligible mass which is also emitted from the nucleus The anti-neutrino is the antiparticle of a neutrino Elect...
Nuclear Energy Levels In the same way that electrons can exist in excited states, nuclei can also exist in excited states After an unstable nucleus emits an alpha particle, beta particle or undergo...
Deviations from Rutherford Scattering In the Rutherford scattering experiment, alpha particles are fired at a thin gold foil Some of the alpha particles are found to come straight back from the gol...
Nuclear Scattering Electrons accelerated to close to the speed of light have wave-like properties such as the ability to diffract and have a de Broglie wavelength equal to: Where: h = Planck's con...
