Identify the mechanism of transport used in this location across the simple cuboidal cell of the proximal convoluted tubuleChoose from the following:(A) facilitated diffusion(B) simple diffusion(C) active transport(D) secondary active transport **Diagram Explanation: Amino Acid and Sodium Transport**This diagram depicts the mechanism of transport for amino acids across the intestinal brush border, highlighting the role of sodium ions (Na⁺) and energy in the form of ATP.- **Brush Border:** The top section labeled "brush border" represents the microvilli-covered surface of the intestinal epithelial cells, where nutrient absorption occurs.- **Amino Acid and Sodium Transport:** Amino acids are co-transported with sodium ions (Na⁺) across the membrane into the cell. This is indicated by the circular transport protein near the top of the diagram, outlined in a red square.- **Sodium-Potassium Pump (ATPase):** Beneath the brush border, there is an ATP-driven pump. This is shown by the directional arrows labeled "ATP," "ADP," and "Pᵢ" (inorganic phosphate), demonstrating ATP hydrolysis. This pump actively transports Na⁺ out of the cell and potassium ions (K⁺) into the cell.- **Ion Flow:** The arrows indicate the flow of Na⁺ into the cell with the amino acids at the top, and the exchange of Na⁺ out and K⁺ in at the bottom via the sodium-potassium pump.This system illustrates secondary active transport where the energy from ATP is used to maintain ion gradients, facilitating the intake of amino acids through symport with sodium ions.

The cell membrane or plasma membrane is a semipermeable membrane that does not allow anything and everything to enter the cell. Hence substances that need to be taken in or those that need to be removed move through the cell membrane by various mechanisms. The transport of substances across the membrane may or may not use energy. Smaller and uncharged molecules move freely like gases oxygen and carbon dioxide, others need propers points of entry and facilitators to achieve the movement. Correct Option - (D) - Secondary active transport. The image shows that the amino acid is taken in the cell transporting it along with Na+ ion. In a subsequent step, the Na+ ion is transported out of the cell by exchanging it for a K+ ion. This is a form of active transport because it uses energy but not in the form of ATP and hence it is named secondary active transport. It utilizes energy generated by creating an electrochemical gradient across the membrane. There are two types of secondary active transport - Co-transport as shown here where both molecules are transported inside the cell together or counter- transport where one molecule travels in and in exchange another molecule moves out. Incorrect Options:- facilitated diffusion makes use of special channels and channel proteins but the substance being transported moves along the concentration gradient.- Simple diffusion the substance just diffuses inside the cell along the concentration gradient.- Active transport uses energy in the form of ATP to move molecules against their concentration gradient.