Cells are the basic units of life. In living organisms, cells are responsible for carrying out some specialized functions that include the taking in of nutrients, converting the nutrients into energy, among other tasks (Goodman, 2002). The human cell contains the plasma membrane, ribosomes, nucleus, mitochondria, lysosomes and peroxisomes, Golgi apparatus, endoplasmic reticulum, endoplasm, cytoskeleton, and cytoplasm (Stein, 2012). The plasma or membrane is the outermost covering of the cell. The layer acts as a gatekeeper and regulates the inward and the outward movement of different materials to and from the cell.
There are only two ways through which substances can leave or enter a cell. They include the passive and active forms. The passive movement of materials is facilitated by the processes of simple diffusion, facilitated diffusion, and osmosis (Stein, 2012). All the three methods of passive transport of elements have a characteristic similarity since they do not need energy emanating from the cells to perform their functions although they are all different (Goodman, 2002). Diffusion involves movement of molecules from a highly concentrated area to one that has a low concentration (Stein, 2012).
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"Differences and Similarities of the Processes of Diffusion".
Simple diffusion involves the movement of non-polar molecules across the cell membrane, which is the simplest form of movement. Additionally, small polar molecules, such as urea and water, can also move through simple diffusion (Goodman, 2002). This process depends on particle sizes and their polarity. The difference between simple diffusion and facilitated diffusion is that the later involves facilitation by proteins that are part of the membrane structure. The proteins have channels which are in the form of hollow cores, which enable small polar molecules and ions to move through them across the membrane (Stein, 2012).
Unlike the diffusion process, which involves the movement of ions and polar molecules, osmosis involves the movement of water from a highly concentrated region to a region of low concentration lowly concentrated (Stein, 2012). The movement of water by osmosis is highly influenced by concentration of a solute in the water. Active transport, unlike the passive form of transport, involves the movement of molecules against the normal concentration gradient through a semipermeable membrane by carrier proteins. Since active transport involves a movement from a low concentration to a high concentration region, energy is required to facilitate the process (Stein, 2012).
The major similarity between facilitated diffusion and simple diffusion is that both their movements take place down a concentration gradient, from a higher concentration to a lower concentration and do not therefore need energy to take place (Stein,2012). They are both passive processes. Similarities between active and passive transport of materials across cell membranes is that both involve the movement of ions in and out of a cell (Stein, 2012). Similarly, both processes ensure that there is a maintained equilibrium of different substances in and out of the cell thus, maintaining homeostasis. Additionally, the major similarity between osmosis and diffusion is that both processes are passive processes and do not require energy to take place (Stein, 2012). Their main difference is that diffusion involves the movement of particles that are randomly moving in or out of the cells and an increase in temperature increases the movement of the particles. Conversely, osmosis involves a free movement of water particles from a region of low solute concentration to a region of high solute concentration (Stein, 2012).
The similarities and differences of the processes of active transport, osmosis, facilitated diffusion, and simple diffusion clearly illustrate that all the processes have the similar function, which is the transportation of materials across the cell membrane in and out of the cell. However, the transport processes perform their tasks in different ways, which is their major difference. Despite their capacities of transporting different materials, all their results are to facilitate the transport process.
