lesson 1: Present continuous

Study this example situation: I’m working.please be quiet.This mean: I’m working now, at the time of speaking.The action is not finished. Am/is/are  + –ing is the present continuous: I am doing something = I’m in the middle of doing it, I’ve started doing it and I haven’t finished: The weather is nice at the moment […]

Chapter 11 : 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 that we will describe here. Meiosis in a diploid organism consists of two rounds of […]

Chapter 10 : meiosis

The sequence of events during meiosis involves two nuclear divisions ( meiosis I and meiosis II ). Prophase 1 In prophase 1 of meiosis, the DNA coils tighter, and individual chromosomes first become visible under the light microscope as a matrix of fine threads. Because the DNA has already replicated before the onset of meiosis, […]

Chapter 4d: 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 energy, each term participating for ½R. As a solid has 3 dimensions, Cv=3R However, this […]

Chapter 4c: 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, be creased or smashed or can be very rigid. As explained at the beginning of […]