Chapitre 5 : les enzymes

Les enzymes (“dans la levure») sont des catalyseurs de réactions chimiques des systèmes biologiques. La plupart des enzymes sont des protéines et ils utilisent souvent des ions métalliques ou des groupes prosthétiques comme les vitamines qui vont aider à la catalyse. Beaucoup de troubles génétiques héréditaires résultent d’une défectuosité ou même une absence totale d’une […]

Chapter 2a: acid-base reactions

In this module we will review one of the main types of reaction of chemistry. Reactions can indeed be classified in 3 major categories: Acid-base reactions Redox (reduction and oxidation) reactions Solubility reactions (dissolution and precipitation) The two last reaction types are seen in other sections of our lessons. We will here focus on acid-base […]

Chapter 1: history of chemistry and chemical reactions

It is often useful to take a look on the history of something to understand it. That is how we will begin our lessons about chemistry. As far as we can go, chemistry started with the discovery of fire, which is basically the combustion of a reactant to obtain heat from it. Later, different metals […]

Chapter 5 : exercices and exam questions (probability)

Problem 1: A marketing survey indicates that 60% of the population owns an automobile, 30% owns a house, and 20% owns both an automobile and house. Calculate the probability that a person chosen at random owns an automobile or a house, but not both. (A) 0.4               (B) 0.5                     (C) 0.6               (D) 07              (E) 09 Problem […]

Chapter2: torque and angular momentum in circular motion

Definitions: the torque and angular momentum are defined as vector products of position, force and momentum. Suppose a forceacts on a particle whose position with respect to the origin 0 is the displacement vector . Then the torque “about the point 0 and acting on the particle,” is defined as: Now suppose the particle has […]