One substance has no membrane transporters to move it but can diffuse freely through open leak channels if there is a concentrat
ion gradient. Initially, this substance's concentrations in the filtrate and extracellular fluid are equal. Later, however, the active transport of Na+ and other solutes creates a gradient by removing water from the lumen of the tubule where it is located. What substance is this?
There are two large ovoid organs called the thalamus, which form most of the lateral walls of the third ventricle of the brain. A variety of receptors transmit signals from the thalamus to the cerebral cortex. Thalamus is anatomically situated adjacent to the midline third ventricle in the brain.
concentration of the enzyme, concentration of the substrate, and temperature. However there are more than three. A lock and key analogy is used when explaining the specific action of an enzyme with a single substrate.