Final answer:
Active transport involves the movement of substances across the cell membrane against their concentration gradient, utilizing energy. There are two main types, pump transport, exemplified by the sodium-potassium pump, and vesicle transport, which includes endocytosis and exocytosis. Group translocation is a form of active transport in bacteria that alters the substance as it enters the cell.
Step-by-step explanation:
Active transport refers to the movement of substances across the cell membrane, against their concentration gradient, with the help of energy in the form of ATP. The two main types of active transport are pump transport and vesicle transport.
Pump Transport
The best-known example of pump transport is the sodium-potassium pump, which moves sodium (Na+) out of cells and potassium (K+) into cells, using energy from ATP. This creates an electrochemical gradient, which is essential for various cellular processes, including nerve impulse transmission.
Vesicle Transport
Vesicle transport involves the movement of substances into or out of cells by vesicles. The two types are endocytosis, which brings substances into the cell, and exocytosis, which expels substances from the cell. Further subdivision of endocytosis includes phagocytosis (for solids) and pinocytosis (for liquids).
Group Translocation
Group translocation is a specific type of active transport found in some bacteria, where a substance is chemically modified as it is brought into the cell, often making it useful immediately for cellular metabolism.