Characteristics of bacteria
The characteristics of bacteria are: DNA concentration area, but no nucleus and cell wall are formed. Some bacteria have capsules and flagella, but no chloroplasts, and can multiply rapidly and form spores.
(1) morphological characteristics:
Under the microscope, the morphology of different bacteria can be said to be varied and colorful, but as far as a single organism is concerned, its basic morphology can be divided into three types: spherical, rod-shaped and spiral. Although it is a unicellular organism, many bacteria often grow in pairs, chains and clusters, such as diplococcus (pneumococcus, also known as pneumococcus), streptococcus, tetracoccus, octococcus, staphylococcus and so on.
Besides the three basic forms of cocci, bacilli and spirillus, there are many other forms of bacteria.
(2) Characteristics of structural components:
Bacteria belong to prokaryotes, which are primitive single-celled organisms, with only naked DNA in the nuclear region, including eubacteria (different from fungi) and archaea.
The cell membrane of eubacteria contains lipids linked by ester bonds, the cell wall contains unique peptidoglycan (except Mycoplasma imperforata), and there is generally no intron in DNA (but there are exceptions in recent years).
Bacteria, actinomycetes, cyanobacteria (also called cyanobacteria), mycoplasma, rickettsia and chlamydia are all true bacteria.