Question

Please summarize this chapter typed clearly.

Diffusion Is a passive process of transport. A single substance tends to move from an area of high concentration to an area of low concentration until the concentration is equal across a space. Facilitated transport Facilitated diffusion is the process of spontaneous passive transport of molecules or ions across a biological membrane via specific transmembrane integral proteins. Channels The integral proteins involved in facilitated transport are collectively referred to as transport proteins, and they function as either channels for the material or carriers. In both cases, they are transmembrane proteins. Aquaporins Are channel proteins that allow water to pass through the membrane at a very high rate. Osmosis Is the movement of water through a semipermeable membrane according to the concentration gradient of water across the membrane, which is inversely proportional to the concentration of solutes. Tonicity describes how an extracellular solution can change the volume of a cell by affecting osmosis. A solution's tonicity often directly correlates with the osmolarity of the solution Endocytosis Is a type of active transport that moves particles, such as large molecules, parts of cells, and even whole cells, into a cell. Phagocytosis Is the process by which large particles, such as cells or relatively large particles, are taken in by a cell. Exocytosis Exocytosis is a form of active transport and bulk transport in which a cell transports molecules out of the cell by secreting them through an energy-dependent process.

Answer 1

All the above mentioned are different mechanisms of transport in which some processes make use of energy while others use a passive mechanism. Diffusion and osmosis is based on the movement of substance from a region of higher concentration to lower concentration. One thing that distinguishes osmosis and diffusion is that in osmosis the movement takes place across a semipermeable membrane. In the case of facilitated transport just as the name suggests the movement is facilitated by certain proteins. Actually these proteins are transmembrane integral proteins. In case of channels these are also integral transmembrane proteins that act as carriers which facilitate the transport. Aquaporins are a class of channel proteins that allow the movement of water molecules. Tonicity is a term that is directly related to osmosis which is related to effect of extracellular solution on the volume of a cell. Endocytosis is the movement of materials into a cell. Exocytosis is just the reverse of endocytosis which moves contents out of the cell. Exocytosis secretes the molecules inside a cell by an energy dependent process. Phagocytosis is the engulfment of large particles into the cell. These are the processes that are commonly found in the transport of materials into or out of the cell in which some processes are enabled by certain proteins, while others use energy.