It is a thin, soft, fragile, and elastic semipermeable membrane that is close to the inside of the cell wall and surrounds the cytoplasm. The main chemical components are phospholipids, proteins and a small amount of sugars. Except for mycoplasma, there is no cholesterol in the cell membrane of prokaryotes

① Able to selectively control the transport of nutrients and metabolites inside and outside cells;

② Structural barrier to maintain normal intracellular osmotic pressure

③Important place for synthesizing components related to cell wall and glycocalyx;

④The membrane contains enzyme systems related to energy metabolism such as oxidative phosphorylation or photosynthetic phosphorylation, so it is the energy production base of cells;

⑤The insertion site of the flagellum basal body and the functional site of flagellum rotation

Intermediates

Thylakoid

chromophore

carboxysome

It is a general term for all translucent, gelatinous, and granular substances surrounded by the cytoplasmic membrane except the nuclear area. Contains ribosomes, inclusions, bubbles and other substances.

Also known as the ribosome, it is the place where polypeptides and proteins are synthesized. It is a 70S particle and consists of two subunits, 50S and 30S. The chemical components are protein and RNA. Prokaryotic ribosomes are often distributed in the cytoplasm in a free state or in a polyribosome state

The larger granular structure inside the cell refers to the storage granules that bacteria store when nutrients are abundant and decompose and utilize them when nutrients are scarce.

In the later stages of its growth and development, spore-forming bacteria form a round or oval, thick-walled, highly refractive, low-water content, and stress-resistant dormant body in the cell, which is called a spore.

Spores are the most stress-resistant structures in the living world

Two genera of G-bacteria

Spores begin to form when the environment lacks nutrients and harmful metabolites accumulate and the cells of spore-forming bacteria stop growing.

3 stages

① The theory of osmotic regulation of cortical expansion: the free water content in the core of spores is low, making nucleic acids and proteins less susceptible to denaturation;

②The cortex contains 2,6-pyridinedicarboxylic acid (DPA) (only found in spores). DPA calcium salt can improve the heat resistance and antioxidant capacity of spores;

③The cortex is composed of unique spore peptidoglycan, thick and dense

Heat-resistant enzyme

concept

Toxic to lepidopteran larvae

cyst

Mucospores, bdelloid spores, exospores, etc.

A type of genetic material that exists outside the nucleus or is integrated into the nuclear chromosome. Most of it is composed of DNA molecules. Small circular DNA molecules that can replicate themselves

It can self-replicate and have stable inheritance. It can also be inserted into bacterial chromosomes or copy and increase value together with the exogenous DNA fragments it carries. It can be transferred alone or together with the chromosome fragments.