The main mechanism by which microorganisms absorb nutrients

Active transport of source C source nSource Inorganic salts.

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.

Simple diffusion: diffusion from a place with a high concentration to a place with a low concentration, without the need for carrier proteins and ATP on the membrane to facilitate diffusion: not limited by concentration, the carrier protein is required and ATP is not actively transported:

Concentration is not limited and requires a carrier and ATP group shift: The solute undergoes a change in molecular structure before and after transport, requiring a carrier and ATP

The main square shed answer for microorganisms to absorb nutrients is ().

a.Active transportation.

b.Simple draft and bi diffusion.

c.Facilitated diffusion.

d.Group translocation.

Correct Answer: Active Shipping.

Answer]: B In order to meet the needs of metabolic reaction speed, Min Qiantan usually has a high concentration of nutrients, and when it is the same as P. bridge, it has to continuously absorb nutrients from outside the cell to the cell, so the active transportation mode of reverse concentration difference and energy consumption is the most common.