What Is Active Transport?

Active transportation refers to the transportation of substances along the reverse chemical concentration gradient (that is, substances move from low concentration areas to high concentration areas). Active transportation not only requires the use of a specific transfer protein molecule embedded in the cell membrane as a carrier (That is, each substance is transported by a special carrier), and must also consume the energy produced by cell metabolism to complete. First, the carrier protein obtains energy from the energy released by the hydrolysis of ATP and converts it into an activated carrier, which combines with substances inside or outside the membrane to form a complex called an ion pump or proton pump.

Chinese name: Active Transportation

English name: active transport ^[1]

The characteristics of active transportation are:

Reverse concentration gradient (reverse chemical gradient) transportation;

Process that requires energy (directly powered by ATP) or releases energy

The main energy sources required for active transportation are:

1. Ion gradient dynamics in coordinated transportation;

2. ATP-driven pump gains energy by hydrolyzing ATP

In fact, it is Na + -K + ATPase, which is generally considered to be a tetramer composed of two large subunits and two small subunits. Na + -K + ATPase is

Calcium ion pump is very important for cells, because calcium ions are usually related to signal transduction, and changes in calcium ion concentration will cause the response of intracellular signal pathways, leading to a series of physiological changes. Intracellular calcium ion concentration (10-7M) is significantly lower than extracellular calcium ion concentration (10-3M), mainly because of the plasma membrane and

There are three types of proton pumps: P-type, V-type, and F-type.

1. P-type: The carrier protein uses ATP to phosphorylate itself and change conformation to transfer protons or other ions, such as H + pump on plant cell membrane, Na + -K + pump on animal cells, Ca2 + ion pump, H + -K + ATPase (located in gastric epidermal cells, secreting gastric acid).

2. V-type: It is located on the membrane of the vesicle (vacuole) and is composed of many subunits. It hydrolyzes ATP to produce energy, but does not undergo autophosphorylation. Vesicle membrane, plant vacuole membrane.

3. F-type: It is a tubular structure composed of many subunits. H + moves along a concentration gradient, and the released energy is coupled with ATP synthesis, so it is also called ATP synthase. F is oxidative phosphorylation or Abbreviation for photosynthetic phosphorylation coupling factor. F-type proton pump is located in the bacterial plasma membrane,

Cotransport is a type of active transportation that is accomplished by indirectly providing energy. The energy required for the movement of matter across the membrane comes from the electrochemistry of ions on both sides of the membrane

Active transport of this substance

Differences between active and passive transportation

There are three main differences: different starting conditions, different modes of transport, and different results.

Active transport consumes energy released by the cell's metabolism, and passive transport does not consume energy released by the cell's metabolism. Both active and passive transport are small molecule or ion transport methods.

Comparison of active transport free proliferation, assisted proliferation, and active transport

The comparison is as follows:

Compare items	Transportation direction	Do you need a carrier	Whether to consume energy	Representative example
Free diffusion	High concentrationlow concentration;	No need	Not consumed	Oxygen, carbon dioxide, water molecules
Assist in proliferation	High concentrationlow concentration;	need	Not consumed	Glucose enters red blood cells
Active transport	Low concentration-high concentration; reverse concentration difference	need	Consume	Amino acids, various ions enter cells, glucose enters small intestinal epithelial cells