With regard to free proliferation, assisted proliferation, active transport

Free diffusion and assisted diffusion must be from high to low concentrations, because these two kinds of diffusion do not require energy, they only have to rely on external forces. Active diffusion, on the other hand, requires energy and is not limited by concentration, regardless of whether it is low or high concentration when required.

Free diffusion: high concentration to the end of the concentration, no need for carrier, no need for energy-assisted diffusion: high concentration to low concentration, need for carrier, no need for active energy transport:

Low concentration to high concentration, need carrier, need energy in the high school range, don't know if it's the answer you want, hope to help you.

Free diffusion and assisted diffusion are along the concentration gradient, while active transport is not based on the concentration gradient to determine the transport direction, that is, it may be a pro-concentration gradient or an inverse concentration gradient

Do free diffusion and assisted diffusion have to be high concentrations?

Certain. And does active transport have to be low to high concentrations?

Not necessarily.

Our teacher said that active transport doesn't have to be low to high concentration, it depends on what the solute is, like 5% sucrose solution and 10% sucrose solution, it's 5% to 10% flow, right? But isn't the water from high to low? But for this, that's generally true, because we don't usually study water as a solute, right?

First sentence Definitely

The second sentence is not necessarily

Because active transport is mainly the cell to absorb the substances it needs.

Assist in proliferationand free diffusion is passive transport, which is carried out along the concentration gradient of substances without consuming cellular metabolic energy (ATP); Active transportationis active, regardless of concentration.

Assisted diffusion, free diffusion, and cytocytocytosis do not consume energy, and active transportation requires a certain amount of energy to be consumed.

Peculiarity. Active transport is not only to borrow the middle hand with the help of the mosaic in the cell membrane.

The specific delivery of protein molecules on the ground (i.e., each substance is transported by a specialized carrier) and must also be done by consuming the energy produced by cellular metabolism.

First, carrier proteins.

Energy is obtained from the energy released by ATP water and converted into an activation carrier, which combines with substances inside or outside the membrane to form a complex called an ion pump or proton pump.

Assisted diffusion generally refers to facilitated diffusionThe transmembrane transport of substances through the membrane is mediated by special proteins (including carriers and channels) on the membrane, and the paraelectro-chemical gradient is carried out. There are two main modes of transport: one is carrier-mediated facilitated diffusion; The second is channel-mediated facilitated diffusion.

Facilitated diffusion belongs to passive transport, and the main characteristics of passive transport are: the process of transporting substances does not need to consume energy, and it is a "passive" process with the "help" of special proteins on the cell membrane to carry out transmembrane transport along the concentration gradient or potential gradient.

Channels to assist in diffusion:

Different channels have different permeability to different ions of the finger bonds, i.e., ion selectivity, which is determined by the structure of the channel, allowing only ions with a specific ion radius and charge to pass through.

According to the different ion selectivity, the channels can be divided into sodium channels, calcium channels, potassium channels, chlorine channels, etc. However, the ion-selectivity of the channel is only relative rather than absolute, for example, sodium channels are permeable to ammonia ions in addition to being mainly permeable to sodium ions, and even slightly permeable to potassium ions.

Active Transport, Free Proliferation and Assisted Proliferation? The concept must be understood, otherwise it is useless to give more examples. Active transport refers to the process by which a substance is transported into or out of the cell membrane under the action of energy with the assistance of a carrier against the concentration gradient (moving from low to high concentration).

Such as potassium, proton transport, amino acids, nucleotides, polysaccharides, peptides, and even proteins. Generally speaking, it is a substance with a larger molecule and fewer ions in the cell. Free diffusion means that substances are transported from the high side through the cell membrane to the side with low concentration, such as O2, CO2, N2, glycerol, ethanol, benzene and other substances, which can be transported from the side with high concentration to the side with low concentration, and this mode of transport does not require energy.

Generally, they are small molecules and fatty substances. Gas: CO2O2 Lipids:

Glycerol, fatty acids (similarly compatible) Small molecule organics: ethanol, benzene, urea

Assisted diffusion, also known as facilitated diffusion, refers to a mode of transportation in which non-fat-soluble substances or hydrophilic substances, such as amino acids, sugars and metal ions, enter the membrane without consuming ATP with the help of membrane proteins on the cell membrane. This is not energy-consuming, and is much faster than free diffusion because of the help of protein, so it is more orderly and faster. Such as calcium, iron ions, Na+, NH4+, 3,

Factors influencing free diffusion: the difference in concentration of substances inside and outside the cell membrane--- the difference in concentration of substances inside and outside the cell membrane that assist in diffusion--- and the number of carriers carrying substances on the cell membrane.

--Active transport --- carriers: make a class of proteins on the cell membrane have saturation, specificity, and competition inhibition.

Energy: Energy consumption.

Concentration differenceConcentration difference Number and type of carriers.

Specific saturation requires the consumption of ATP

Active transport: Carrier, energy dissipation, and inverse concentration gradient required. It is mainly macromolecules with poor fat solubility, but there are also certain ions such as potassium ions absorbed by cells.

Free diffusion: along the concentration gradient, no carrier required, no energy consumption. Mainly small molecules or fat-soluble molecules with small molecular weights such as CO2, H20, glycerol.

Assisted diffusion: along the concentration gradient, requires a carrier, and does not consume energy. Mainly some macromolecules with poor fat solubility. Such as red blood cells absorbing glucose.

Sex hormones belong to the lipid class, which is fat-soluble, and generally enters the cell through free diffusion, thus binding to the receptors in the cell to exert its effect.

Amino acids are generally introduced into cells by assisting diffusion or active transport.

Vitamins are divided into water-soluble and fat-soluble, and can be freely diffused and actively transported.

Both free diffusion and assisted diffusion are passive transport, and substances can only be transported from a high-concentration area to a low-concentration area, and no energy is required in the process. The difference between the two is that free diffusion does not require a carrier, while assisted diffusion requires the participation of a carrier.

Active transport requires not only the assistance of a carrier, but also the consumption of energy, and the substance can be transported against the concentration gradient.

Free diffusion does not consume energy, nor does it require the assistance of carrier proteins, relying on the concentration difference between the inside and outside of the cell membrane, from high concentration to low concentration, mainly the transfer mode of some small molecules.

Assisted diffusion does not require energy, but requires carrier proteins, which also rely on the concentration difference between the inside and outside of the cell membrane, from high concentration to low concentration.

Active transport requires energy and carrier proteins, which can be transported from low to high concentrations by reversible concentration gradients.

Answer 1: The substances transported are different: the substances that are actively transported, assisted diffusion, and freely diffused are all ionic and polymer substances; Whereas, endocytosis and exocytosis are the transportation of macromolecular substances. 2. The way in which substances enter and exit the cell is different:

Assisted diffusion and free diffusion are passive transports, which are carried out along the concentration gradient of substances without consuming cellular metabolic energy (ATP); Active transport is active, regardless of concentration; The current mode of transportation of endocytosis is controversial and cannot be judged as active or passive transportation. 3. Whether it needs to consume energy is different: assisted diffusion, free diffusion and endocytocytosis do not consume energy, and active transportation requires a certain amount of energy.

The mode of transmembrane transportation of substances is divided into active transportation.

transport and DU passive transport, in which ZHI passive transport is divided into free diffusion and assisted diffusion.

Dedicated active transportation: the carrier egg is white and energy, which can be transported in reverse concentration, such as: ions, amino acids, glucose and other nutrients.

Assisted diffusion: Carrier proteins are needed and do not require energy, they can only be transported along the concentration, and the higher one notes an example: glucose enters the red blood cells, and the high three plus two more examples of potassium outflow and sodium influx in nerve cells are assisted diffusion.

Free diffusion: No carrier or energy is required, and can only be transported along the concentration, such as oxygen, carbon dioxide, water, glycerol, fatty acids, etc.

It is active transportation.

Active transport is a copy of the substance bai

Cis-or-inverse] concentration gradient, the process of transporting substances into or out of the cell membrane under the action of carrier proteins and energy. Therefore, it is not that it becomes a pro-concentration gradient and becomes an assist, but it also has to be called active transportation, and the definition here is a bit confusing, and it is all conventional.

But there is a special case, that is, when glucose enters red blood cells, it is the same carrier, that is, when the content of glucose in the small intestine is large, it enters the small intestine epithelial cells in the way of assisted diffusion, and when the content of glucose in the small intestine is less, it enters the small intestine in the way of active transport.

However, it is now generally considered to be assisted diffusion, i.e., a carrier is required but does not consume energy.

This explanation is the answer to this tangled question.

Active transportation

With assisted diffusion, bai is not only because of the concentration problem, but also because of the different types of transported substances.

DAOs take a different approach.

Therefore, the version of "if the weight fruit increases the ion concentration outside the membrane and becomes a pro-concentration gradient, then it is active transport or assisted diffusion" is not true, and active transport can not only follow the concentration gradient but also reverse the concentration gradient, but assisted diffusion can only be along the concentration gradient.

Only one substance can be transported by one carrier.

Chloroplasts certainly belong to the biofilm system, but not to the endomembrane system.