How do bacteria absorb and digest nutrients?

Bacteria absorb nutrients from the outside world through permeation and selective absorption of cell membranes; It is digested in the body by enzymes.

The mode of nutrition of bacteria can be divided into two categories: heterotrophic and autotrophic. Most bacteria are heterotrophic, and a few are autotrophic (e.g., chemosynthetic bacteria and photosynthetic bacteria).The junior high school level replied like this:

The mode of nutrition of bacteria is mainly heterotrophic, including parasitism and saprophyticism".

The theory of microbiology section of the way bacteria are vegetative and reproduce.

Bacteria have chloroplasts in their cells and can only use readily available organic matter to thrive and live.

The nutritional mode of bacteria is self-managed and heterogeneous, among which heterogeneous saprophytic bacteria are important decomposers in the ecosystem, so that the carbon cycle can be carried out smoothly. Some bacteria fix nitrogen, which converts nitrogen into a bioavailable form. Bacteria also have a great influence on human activities.

On the one hand, bacteria are the causative agents of many diseases, including tuberculosisEducation Network|Diseases such as gonorrhea, anthrax, syphilis, plague, and trachoma are all caused by bacteria. However, bacteria are also often used by humans, such as the production of cheese and yogurt, the manufacture of some antibiotics, and the treatment of wastewater. In the field of biotechnology, bacteria are also widely used.

First of all, the nutrition of microorganisms includes six major nutrients: carbon source, nitrogen source, energy source, growth factors, inorganic salts and water. According to the different ways of utilization of carbon source and nitrogen source, it is divided into: heterotrophic microorganisms (using organic carbon sources), autotrophic microorganisms (using inorganic carbon sources), amino acid autotrophic microorganisms (using simple nitrogen sources, such as urea and ammonium salts can directly synthesize amino acids), and amino acid heterotrophic microorganisms (using ready-made amino acids).

Except for protozoa (eukaryotic microorganisms) can passEndocytosiswithPinocytosisIn addition to ingesting nutrients, other large classes of microorganisms with cells pass throughPermeability and selective absorption of cell membranesAbsorb nutrients from the outside world. There are 4 ways in which cell membranes transport nutrients, namely simple diffusion, facilitated diffusion, active transport, and group displacement.

1.Pure diffusion.

It is a passive transport, which refers to the transport mode in which many small molecules pass through the hydrophobic bilayer cell membrane passively by physical diffusion without the participation of carrier proteins.

2.Facilitated diffusion.

It refers to a kind of diffuse transport mode in which solutes must be assisted by substrate-specific carrier proteins present in the cell membrane, but do not consume energy.

3.Unsolicited shipping.

It refers to a type of transport mode that must provide energy and transport low concentrations of solutes from the extramembrane environment into the cell membrane through the conformational changes of specific carrier proteins on the cell membrane.

4.Group shift.

It refers to a class of material transport methods that require both the participation of specific carrier proteins and the consumption of energy, which is characterized by changes in the molecular structure of solutes before and after transport.

Microorganisms do not have organs that specialize in ingesting nutrients, they rely on the entire cell surface for nutrient intake, and it is believed that the absorption of various nutrients depends on the action of the cytoplasmic membrane, and there are many small pores on the cytoplasmic membrane, and various nutrients pass through the cell membrane through different absorption methods, and whether nutrients can enter the cell depends on three factors.

1.The properties of the nutrients themselves (relative molecular weight, mass, solubility, electronegativity, etc.) 2The environment in which the microorganism is located (temperature, pH, etc.) 3

According to the characteristics of the material transport process, the permeable barriers of microbial cells (protoplasmic membrane, cell wall, capsule, etc.) can be divided into free diffusion, facilitated diffusion, active transport, and group transfer.

1. Free proliferation.

Free diffusion is also known as simple diffusion The protoplasmic membrane is a semi-permeable membrane Nutrients diffuse through the pores on the protoplasmic membrane from a high concentration of extracellular environment to a low concentration of intracellular Free diffusion is non-specific, but the size and shape of the watery pores on the protoplasmic membrane have a certain selectivity for the nutrient molecules involved in pore diffusion It has the following characteristics: 1The substance does not undergo any reaction during diffusion 2Does not consume energy and cannot be transported against concentration 3

The rate of transport is proportional to the difference in the concentration of substances inside and outside the membrane Free diffusion is not the main way for microbial cells to absorb nutrients Water is the only molecule that can freely pass through the protoplasmic membrane by diffusion Fatty acids Ethanol Glycerol Some gases (O2 CO2) and some amino acids can also enter and exit the cell through free diffusion to a certain extent.

2. Facilitating diffusion.

In this process, (1) no energy is consumed, (2) the molecular structure of the substances involved in the transport does not change, (3) the reverse concentration transport cannot be carried out, (4) the transport rate is proportional to the concentration difference between the inside and outside of the membrane, (5) the nutrients that enter the cell through facilitated diffusion mainly include amino acids, monosaccharides, vitamins and inorganic salts, etc But there are also microorganisms that transport the same substance by more than one carrier protein.

In the process of body metabolism, many nutrients needed by the human body need to be dissolved in water to be transported by the blood and absorbed by tissues.

The macromolecular nutrients starch, protein, and fat ingested by the human body from food must be digested by the digestive tract before they can be absorbed, and the digestive system is composed of the digestive tract and digestive glands, and the small intestine is the main organ for digesting food and absorbing nutrients The food ingested by the human body from the outside world depends on the digestive system for digestion and absorption The small intestine is the main organ for digesting food and absorbing nutrients

So the answer is: digestion; Absorb; Small intestine.

Summary. Hello dear, glad to answer for you! The nutrients that bacteria must replenish from the outside are water, carbon sources, nitrogen sources, inorganic salts, growth factors.

Hello dear, glad to answer for you! The nutrients that bacteria must replenish from the outside are water, carbon sources, nitrogen sources, inorganic salts, growth factors.

Pro, the nutrients that bacteria must replenish from the outside are:1Water:

80-90% of the wet weight of bacteria is water. The chemical reactions, absorption and penetration, secretion, and excretion of nutrients in the process of bacterial metabolism all require water to carry out. 2.

Carbon source: All kinds of inorganic or organic carbon-containing compounds (CO2, carbonates, sugars, fats, etc.) can be absorbed and utilized by bacteria, as raw materials necessary for the synthesis of bacteria, and also as the main energy for bacterial metabolism**. Pathogenic bacteria mainly obtain carbon from sugars, hexose is the basic component of polysaccharides in bacteria, and pentose is involved in bacterial nucleic acid composition.

3.Nitrogen sources: From molecular nitrogen to nitrogen-containing compounds that can be used by different bacteria.

4.Inorganic salts: potassium, sodium, calcium, magnesium, sulfur, phosphorus, iron, manganese, zinc, cobalt, copper, molybdenum, etc. are inorganic salts required for bacterial growth and metabolism.

In addition to phosphorus, potassium, sodium, magnesium, sulfur, and iron, only trace amounts are required for travel photography. 5.Growth Factors:

Many bacteria also need some compounds that cannot be synthesized by themselves in the process of growth, called growth factors. Growth factors must be supplemented from the outside world, including vitamins, certain amino acids, lipids, purines, pyrimidines, etc.

Bacterial nutrients are those.

Bacterial nutrients are water, carbon sources, nitrogen sources, inorganic salts, growth factors.

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There are many digestive enzymes in the small intestine that break down nutrients in food into small molecules that are soluble in water, which are then absorbed by the villous epithelial cells of the small intestine;

Among them, glucose and amino acids mainly enter the capillaries of the villous epithelial cells of the small intestine, and the fat is broken down into glycerol and fatty acids and mainly enter the capillary lymphatic vessels of the villous epithelial cells of the small intestine.

In addition, food can also be initially digested in the mouth and stomach.

There are saprophytes, like the vast majority of bacteria in the biological kingdom.

There are autogenous bacteria such as cyanobacteria, sulfur bacteria.

There are also parasites, Mycobacterium tuberculosis, pneumococcus.