Transport, also known as transportation, is the transfer of animals, people, and goods from one place to another. The total amount of all transported items is called the freight. Freight may be trucked, shipped by air, or moved by any other mode. Simply put, the act of transporting is defined as the actual movement of an object or an organism from a given point A to a given point B.
There are three types of transport: primary active transport, glycolysis, and multistage transport. In primary active transport, chemical reactions that generate energy are actually used to convert fuel into a product. In this case, energy would be the result of a chemical reaction between a hydrogen atom and an oxygen atom. In the process, the hydrogen atom receives a proton (positive charge), and the oxygen atom receives an electron (negative charge). This reaction creates energy, which becomes the energy needed to move the molecules in the appropriate direction. Thus, the fuel or gas will be burned and the resulting products will be moved to their destinations.
In the case of the first type of transport, known as primary active transport, molecules are moved by diffusion. For instance, during the digestive process, food particles are transported through the colon, esophagus, and intestines in order to be broken down into nutrients for the body. During this process, some substances are transported through the intestinal wall while others are carried via the lymph system and other circulation systems. Some substances in the feces remain in the intestinal lining as waste, while others are moved into the blood stream and eventually deliver these nutrients to all parts of the body.
The second type of transport, known as glycolysis, occurs when two substances combine to change a small amount of their mass into another substance. For example, fatty acids convert into glucose, and oxygen reacts with glycogen to form glycogen, a compound that can be utilized for energy production. Glycogen is transported from the liver to various cells in the body, but the process is slow, and glycolysis is a complete reaction rather than a diffusion process.
The third type of movement is called autotrophic movement. This occurs when the molecules are held together by an electrochemical gradient. The gradient results from the uneven distribution of positive and negative charges within the cytoplasm, which causes the dimerization of the hydrogen atoms. As the molecules move, they push the atoms out of the cytoplasm, allowing the creation of ions, free radicals, and new compounds. As this process continues, the cytoplasm becomes more dense and the molecules become heavier, until they finally begin to float on the surface of the water.
A concentration gradient is a concentration gradient that occurs on a surface because of surface tension. For instance, when two containers are placed on top of each other at a specific angle, the concentration of each molecule is different. Because of this, these two containers cannot mix completely. The molecules will only mix to some extent, and only part of them will be in a constant concentration. In order for these compounds to fully blend, they must travel across the surface of one container and into the other one.
The concentration gradient that occurs in the cytoplasm is also true of other substances, such as fat and water. As fluids flow through the cells in our body, they take on only molecules that can pass through the cell walls. Once the substances reach a certain concentration, they become immobile. They do not move any further, so they are stuck in one place. In order for a substance to be diffuse, it must be in a continuous state of motion. Thus, most substances, including water and fat, diffuse through lipid membranes, but are composed of very small molecules until they become larger molecules like lipids and fats.
Most substances are not in a constant state of motion, which explains why most substances are easily absorbed by cell membranes. Lipids are transported to the ends of the cell membrane, where they sit waiting to be picked up by a passing cell. When a cell obtains a substance that could not pass through the cell’s lipid membrane, it picks up the substance, spreads it across the lipid membrane, and attaches it to the interior of the cell. The transport of substances through the plasma membrane is how cells get their components to where they are needed.