Table of Contents
germ-theory-of-disease
The germ theory of disease is a scientific theory that states that microorganisms are the cause of most diseases. The theory was developed by Louis Pasteur and Joseph Lister in the 19th century.
History and Experiments
The history of the periodic table begins with the recognition of patterns in the elemental abundances found in the Earth’s crust. The first person to notice these patterns was the English chemist John Dalton, who in 1803 published a table of relative atomic weights, which showed that the elements in the table occurred in a repeating pattern.
Dalton’s table, however, was not based on any underlying principle, and so it was not until the 1860s that the Russian chemist Dmitry Mendeleev began to develop a periodic table based on the idea that the elements are arranged in order of increasing atomic weight and that they also exhibit repeating chemical properties.
Mendeleev’s table was not perfect, as he was unable to predict the existence of some elements, but it was nevertheless a significant advance in the field of chemistry. Since then, the periodic table has been amended and refined many times, and it is now considered to be the most accurate representation of the chemical elements currently known.
The modern periodic table is based on the atomic number of an element, which is the number of protons in the element’s nucleus. The atomic number increases from left to right across a row in the table, and from top to bottom down a column. This arrangement reflects the increasing atomic weight of the elements.
The elements are also divided into periods and groups. The periods are numbered 1 through 7, and the groups are denoted by letters (e.g. A, B
Fermentation
is the process by which an organic molecule is converted into an inorganic molecule, usually an alcohol or an acid. The process is often catalyzed by enzymes.
In the fermentation of sugar to ethanol, the sugar is first converted to glucose and then to ethanol. The reaction is catalyzed by the enzyme alcohol dehydrogenase.
Koch’s Postulates
In 1883, Robert Koch developed a set of four postulates to help identify the cause of a disease. The postulates are as follows:
The organism must be isolated from a diseased organism and grown in a pure culture. The organism must cause disease when introduced into a healthy organism. The organism must be re-isolated from the diseased organism. The organism must be identical to the original organism.
Koch’s postulates helped to identify the cause of many diseases and have been used as the foundation for modern microbiology.
Examples of Microbes
There are many types of microbes, but some of the most common are bacteria, viruses, and fungi.
Bacteria are single-celled organisms that can be found almost everywhere in nature. They are incredibly versatile and can survive in a variety of environments, including extreme conditions like high temperatures or low oxygen levels. Bacteria are responsible for many important processes, like breaking down organic matter and producing essential nutrients.
Viruses are tiny, parasitic organisms that can only survive inside other cells. They are incredibly efficient at reproducing and can cause serious diseases in plants and animals.
Fungi are a large group of organisms that include mushrooms, yeast, and molds. Fungi are unique in that they can live both in the soil and in the air. They are important for breaking down dead plant and animal matter, and some fungi can even be used to produce food and medicines.
