Final answer:
The type of transport occurring in the proximal tubule is active transport and secondary active transport.
Step-by-step explanation:
The type of transport that occurs in the proximal tubule is active transport and secondary active transport.
The proximal tubule is responsible for the reabsorption of most of the filtered fluid from the glomerulus. It actively transports ions such as sodium (Na+), chloride (Cl-), and glucose from the tubular fluid into the blood, against their concentration gradients. This is accomplished through the use of specific transport proteins on the luminal surface of the proximal tubule cells.
For example, a Na+/glucose symport protein assists both Na+ and glucose movement into the cell. As Na+ moves down its electrochemical gradient created by the basal membranes Na+/K+ ATPases, glucose is transported against its concentration gradient. The glucose then diffuses across the basal membrane into the interstitial space and is eventually transported into peritubular capillaries.