Endosymbiotic Theory Endosymbiosis Endosymbiosis is where one organism lives within another If the relationship is?beneficial?to both organisms the engulfed organism is not digested For endosymbios...
Spontaneous Generation Pre-existing cells In 1852 Robert Remak made the conclusion that cells divided to form new cells, that is cells came from?pre-existing cells His conclusion was reached after ...
Practical 1: Using a Microscope Many biological structures are too small to be seen by the naked eye Optical (light) microscopes are an invaluable tool for scientists as they allow for tissues, cel...
Stem Cells A?stem cell?is a cell that can?divide?(by mitosis) an?unlimited number of times Each new cell (produced when a stem cell divides) has the potential to?remain a stem cell?or to develop in...
Emergent Properties Multicellular organisms are able to undertake functions that unicellular organisms cannot, e.g. move over vast distances and digest large macromolecules This is a result of prop...
新學(xué)期來(lái)了，相信又有一批新同學(xué)和家長(zhǎng)開(kāi)始接觸AP體系了。美國(guó)的AP課程大概有幾十門(mén)，國(guó)內(nèi)開(kāi)設(shè)的課程可能只有十幾門(mén)。也就是說(shuō)，AP課程的選擇有一定限制。 同學(xué)們需要思考未來(lái)的專業(yè)意向。因?yàn)锳P課程是比較靈活的...
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...
