Mole & Avogadro Constant The?Avogadro constant?(NA?or?L) is the number of particles equivalent to the relative?atomic?mass?or?molecular mass?of a substance The Avogadro constant applies to atom...
Relative Masses Atomic Mass Unit The mass of a single atom is so small that it is impossible to weigh it directly Atomic masses are therefore defined in terms of a?standard?atom which is called the...
Structure of an Atom All matter is composed of?atoms, which are the smallest parts of an element that can take place in?chemical reactions Atoms are mostly made up of?empty?space?around a very smal...
Recombinant DNA Technology Recombinant DNA The genetic code is?universal, meaning that almost every organism uses the same four nitrogenous bases – A, T, C & G. There are a few exceptions The g...
Genome Sequencing Projects A genome contains?all of the genes within an organism Advances in technology have allowed scientists to map and sequence the genes within an organism's genome Genome sequ...
Totipotent Cells A?stem cell?is a cell that can?divide?(by mitosis) an?unlimited number of times Each new cell that is produced when a stem cell divides has the potential to?remain a stem cell?or t...
Gene Mutations A?gene mutation?is a change in the sequence of base pairs in a DNA molecule that may result in an altered polypeptide Mutations occur?continuously?and?spontaneously Errors in the DNA...
The Definition of a Community Species?do not exist by themselves in their own isolated environment, they interact with other species forming?communities A community can be defined as: Multiple popu...
Edexcel IGCSE Maths復習筆記 1.9.1 Compound Interest What is compound interest? Compound interest is where interest is paid on the interest from the year (or whatever time frame is being used) befor...
