Bacteria are single-celled organisms of which there are many different types. These bacteria are prokaryotic, that is, they do not have a nucleus. Bacteria have a major influence on people and the environment.
Bacteria on the laboratory
Bacteria are often grown in the laboratory. A liquid or a solid nutrient medium is used for this. Often nutrients are also added to this. Bacteria multiply through binary division. Cell division begins with the doubling of the circular chromosome. Then the cell stretches to separate the two chromosomes. A transverse wall then forms to divide the stretched cell into two daughter cells. The binary division can proceed fairly quickly, some bacteria can divide every twenty minutes under optimal conditions. Under unfavorable conditions, some rod-shaped bacteria can undergo spore formation. Spore formation in the process of forming an endospore, an endospore is a structure in the cytoplasm that consists of a thick spore wall in which the DNA can be stored. If the bacteria itself dies because of bad conditions, the whole bacteria dies except the endospore. It can survive bad conditions and if the conditions are better, the endospore can grow back into a bacterium.
The environment of bacteria
Ideal conditions are determined by a number of different factors; oxygen tension, temperature, acidity and osmotic value. All these factors play a role in the growth of the bacteria.
Oxygen tension
Most bacteria need oxygen, often cannot even grow without oxygen, these are called obligate aerobic. You also have obligatory anaerobic bacteria, which only grow without oxygen. Finally, you also have the facultative anaerobic bacteria, which grow in the presence and absence of oxygen.
Temperature
Each bacterium has a minimum, an optimum and a maximum temperature, the minimum temperature is the temperature at which the bacterium cannot grow lower than that, the optimum temperature is the temperature at which the bacterium grows best. The maximum temperature is the temperature above which the bacteria cannot grow. You can divide the bacteria into 3 different groups based on temperature. Psychrophiles, who have a low temperature optimum of 0 to 15 degrees, mesophiles, who have an optimum temperature of 20 to 37 degrees, and thermophiles, who have a high optimum temperature of 55 to 65 degrees, and extreme thermophiles, who have an optimum temperature of 100 degrees.
Acidity
Just like the optimum temperature, a bacteria also has an optimal acidity at which the bacteria can grow. Most bacteria grow optimally at a pH of 7. There are also bacteria that can grow at a pH of 0.8, these bacteria that can grow at a low pH are called acidophiles.
Osmotic value
Bacteria also need water just like most organisms. The bacteria grow best in an isotonic environment. If there is a low osmotic value in a nutrient medium, the bacteria will absorb water by means of osmosis. If there is a high osmotic value, the bacteria will lose water and die.