1. Briefly explain about Sodium-potassium (Na+-K+) pump?2. Distinguish between Endocytosis and exocytosis ?
1. The sodium-potassium pump is a vital transport protein found in the cell membranes of all animal cells. It helps maintain the cell's internal concentration of sodium and potassium ions by actively transporting them against their concentration gradients. The pump uses energy from ATP to pump three sodium ions out of the cell in exchange for two potassium ions entering the cell. This process is important for regulating cell volume, maintaining membrane potential, and transmitting nerve impulses.
2. Endocytosis is a cellular process in which cells take in molecules or particles by engulfing them in a section of the cell membrane, forming a vesicle. This process is used to internalize substances such as nutrients, signaling molecules, or pathogens. Exocytosis, on the other hand, is the reverse process in which cells release molecules or particles by fusing vesicles containing the substances with the cell membrane, allowing them to be expelled from the cell. Endocytosis brings substances into the cell, while exocytosis releases substances from the cell.