What are the two main types of active transport in cells?

• A. Primary and secondary active transport
• B. Osmosis and diffusion
• C. Phagocytosis and pinocytosis
• D. Facilitated diffusion and endocytosis

Answer: (A)

Verified step by step guidance

1. Begin by understanding the concept of active transport. Active transport is a cellular process that moves molecules across a cell membrane against their concentration gradient, requiring energy input, usually in the form of ATP.
2. Identify the two main types of active transport: primary and secondary active transport. Primary active transport directly uses energy to transport molecules, while secondary active transport uses the energy from the electrochemical gradient created by primary active transport.
3. Differentiate between primary and secondary active transport. In primary active transport, ATP is used directly to transport molecules, such as the sodium-potassium pump. In secondary active transport, the movement of one molecule down its gradient provides the energy to transport another molecule against its gradient.
4. Consider other processes mentioned in the options: osmosis and diffusion are passive transport processes, not requiring energy. Phagocytosis and pinocytosis are forms of endocytosis, which involve the cell engulfing materials, but are not classified as active transport types.
5. Facilitated diffusion is a passive transport process that uses transport proteins to move molecules across the membrane without energy input. Endocytosis is a process of active transport but is not one of the two main types of active transport.