DNA is a polymer ( a large molecule that contains repeating units) composed of 2’ deoxyribose (a five-carbon sugar), phosphoric acid, and the four nitrogen containing bases denoted A, T, G and C. The chemical structures of the bases are
Chapter 5 : stem cells
What is a stem cell? Ultimately, every cell in the human body can be traced back to a fertilized egg that came into existence from the union of egg and sperm. But the body is made up of over hundreds
Chapter 4 : specific features of meiosis
Meiosis has three unique features : The mechanism of cell division varies in important details in different organism. This is particularly true of chromosomal separation mechanism, which differ substantially in protists and fungi from the process in plants and animals
Chapter 2 : Replication
1) Definition The DNA replication is one of the key mechanisms of cell cycle. It is a highly regulated biological process in which new synthesis and repair mechanisms ensure the integrity of the genome. S phase or replication phase follows
Chapter 1 : TRANSCRIPTION
The central dogma of molecular biology The central dogma is the classic sequence of events : DNA produces RNA by transcription and RNA produces proteins ( structural proteins and Enzymes ) by translation . Transcription: making of RNA (taking the
Chapter 10 : solids – conductivity
Electric conduction Some solids are conducting the electricity and some are not. We will explain here from where the conductivity comes and the difference between a conductor and an insulator. The conductivity is explained by the band theory. We have seen in
Chapter 9 : Phase diagram
The state of compounds depends on the temperature and on the pressure. We map the states of the matter on the diagram of phases. The pressure is put as ordinate and the temperature as abscise. The states are separated by
Chapter 8 : Solids – lattice energy
In gases, the heat capacity was a resultant of translation, vibration and rotation. In a solid, there is no translation and no rotation. The atoms may vibe around their equilibrium position. The vibration involves a potential energy and a kinetic
Chapter 7 : Solids – crystallography
A characteristic of the solids is that they have their own shape. Liquids are taking the shape of their recipient and gases take all the available space. So solids have their own shape but some are malleable, can be cut,
Chapter 6 : Liquids
Liquids Liquids are a condensed state: the volume of a liquid does not change by much when a pressure is applied. A liquid is a fluid: it has not its own shape and molecules can move inside it. As said previously, liquids