Question

The concentration of glucose in the blood at P, and in the fluid at Q, is 0.1 per cent. The concentration of glucose in the fluid at R is 0.0 per cent.

Use information from the diagram, and your own biological knowledge, to explain the change in glucose concentration from point P through to point R.

Answer 1

The change in glucose concentration from point P to point R can be explained by the process of selective reabsorption in the kidneys. In the kidney, glucose is filtered from the blood at the glomerulus, forming the glomerular filtrate. The glomerular filtrate then passes through the renal tubules, where selective reabsorption occurs.

At point P, the concentration of glucose in the blood is 0.1 per cent, which is the same as the concentration in the fluid at Q. This suggests that at point P, glucose is freely filtered from the blood into the glomerular filtrate without being selectively reabsorbed. Therefore, the concentration of glucose remains constant from point P to point Q.

However, at point R, the concentration of glucose in the fluid is 0.0 per cent. This indicates that glucose has been selectively reabsorbed from the glomerular filtrate back into the blood. In the renal tubules, specialized transporters actively reabsorb glucose molecules from the filtrate and transport them back into the bloodstream. This process ensures that glucose, which is an important energy source for the body, is retained rather than being excreted in the urine.

The change in glucose concentration from point P to point R is due to the selective reabsorption of glucose in the kidneys. As the glomerular filtrate passes through the renal tubules, glucose is actively transported back into the bloodstream, leading to a decrease in its concentration from point P to point R. This mechanism helps maintain a stable blood glucose level and prevents the loss of valuable energy resources.

Answer 2

Step-by-step explanation:The change in glucose concentration from point P to point R can be explained by the process of diffusion. Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration.

At point P, the concentration of glucose in the blood is 0.1 percent. This means that there is a higher concentration of glucose in the blood compared to the surrounding fluid. Due to the concentration gradient, glucose molecules will tend to move from the blood to the surrounding fluid through diffusion. As a result, glucose molecules will diffuse from point P towards point R.

As the glucose molecules move from point P towards point R, they will continue to spread out and mix with the surrounding fluid. At point Q, which is between P and R, the concentration of glucose in the fluid will increase due to the diffusion of glucose from the blood. However, the concentration at point Q will still be lower than the initial concentration at point P.

As the glucose molecules continue to diffuse towards point R, the concentration gradient decreases. Eventually, at point R, the concentration of glucose in the fluid is 0.0 percent. This means that all the glucose molecules have diffused from the blood and mixed with the fluid, resulting in an equal concentration of glucose in the blood and the fluid at point R.

In summary, the change in glucose concentration from point P to point R is due to the process of diffusion, where glucose molecules move from an area of higher concentration (point P) to an area of lower concentration (point R) until equilibrium is reached.