Cell Structure and Function Quiz

Cell Structure and Function

• Cell Membrane: It plays an important role in cell signaling & cell recognition. The cell membrane is a phospholipid bilayer. Proteins in the membrane help in signal transduction. Proteins are also involved in transporting materials.
• Cell Proteins: Proteins have two functions: one part interacts with the extracellular fluid and the other part interacts with the intracellular fluid.
• Cell Membrane Proteins: Transmembrane proteins pass completely through the membrane, while peripheral proteins are attached to the inner or outer face, or embedded in one side of the membrane.
• Cell Membrane Structures: Gap junctions, desmosomes, tight junctions, and channels allow the exchange of gases and other materials within the cell.
• Fluid Mosaic Model: The cell membrane is a fluid structure with proteins embedded within the phospholipid bilayer.
• Mitochondria: It is also called the powerhouse of the cell. It is involved in generating ATP (adenosine triphosphate).
• Golgi Apparatus: It is a refining/packaging system for cellular products. It is packaged in sacs called vesicles.
• Ribosomes: Plays a complex role in protein synthesis.
• Nucleus: The largest organelle in the cell. It contains the genetic material (DNA) and controls cellular activities.
• Cytoplasm: The fluid-like substance inside the cell, and all the organelles are suspended in it.
• Cell Transport: It transports substances in and out of the cell.
• Active Transport: The mechanism that requires energy. It is also called uphill transport because any substance may be transported against its concentration gradient.
• Passive Transport: The transport of substances does not require energy. It is also called downhill transport. Examples are simple diffusion and facilitated diffusion, which may move substances across the membrane.
• Simple Diffusion: It is the movement of materials from an area of high concentration to an area of low concentration. This can be influenced by factors such as temperature, surface area, and concentration gradient.
• Facilitated Diffusion: Substances move across the membrane with the help of carrier proteins.
• Bulk Flow: Movement of large quantities of molecules from an area of high pressure to an area of low pressure - Bulk flow is in the lungs (example).
• Filtration: It is the movement of water and small dissolved particles from an area of high hydrostatic pressure to an area of low hydrostatic pressure.