Cell transport
Cell transport refers to the movement of ions, molecules, and particles across the membrane of a cell. According to online sources, the most significant feature of a phospholipid cell membrane is its selective permeability (Foundation, 2020). Permeability regulates the passage of unwanted materials, and only small molecules or ions penetrate through. The cell structure is thus able to dictate the transportation of materials in and out of it. Additionally, the phospholipid bilayer regulates the types of molecules that pass through due to its molecular make-up.
A good example is the restriction of polar molecules (H2O) and calcium ions (Ca2+) and the passage of water-hating molecules such as oxygen (O2) and Carbon dioxide (CO2)
Active transport energy in the form of ATP is required to facilitate the movement of substances from areas of low concentration to areas of high concentration against the concentration gradient. The process is “active” because it directly involves the use of energy required to pump out ions and molecules, in this case, sodium-potassium pump. Protein carriers are used in Active transport to change conformation when hydrolysis of ATP emerges (Khan Academy, 2020). Contrary, in passive transport, no energy is required to facilitate movement. The primary process involved is diffusion, which enables change of substances from areas of high concentration to regions of low concentration across the semipermeable membrane. Diffusion is achieved when there is equal concentration all over the space (Khan Academy, 2020). The semipermeable membrane hinders the passage of large molecules and charged ions but allows uncharged substances like oxygen and carbon dioxide to pass through.
Additionally, through vesicle transport, larger molecules pass through the phospholipid cell membrane. Molecule movement involves bubbles like sacs initially formed by the cell membrane. Endocytosis and Exocytosis form the basis of vesicular transport.
In conclusion, cell transport involves numerous activities across the cell membrane. The structure of the membrane (semi-permeable) provides essential characteristics which dictate transportation of molecules, charged and uncharged ions and other particles. Cell transport can either use ATP energy (Adenosine Trisphosphate) to facilitate the process of Active transport or no energy to foster passive transport. Besides, transport can require basic contribution use of pumps/proteins. Lastly, vesicle transport also aids the movement of substances across the cell.
Works Cited
Foundation, CK-12. “Cell Transport”. CK-12 Foundation, 2020, https://www.ck12.org/biology/cell-transport/lesson/Cell-Transport-Advanced-BIO-ADV/.
“Sodium Potassium Pump (Video) | Khan Academy”. Khan Academy, 2020, https://www.khanacademy.org/science/high-school-biology/hs-energy-and-transport/hs-passive-and-active-transport/v/sodium-potassium-pump-video.