Which reagent is used to detect the presence of simple sugars?

Tonicity is the ability of a solution to cause water movement across a semi-permeable membrane, such as the cell membrane. In the lab, tonicity can be tested by observing the effects of different solutions on cells, such as red blood cells or plant cells. However, the items that have been contaminated with blood, such as slides, pipettes, or gloves, cannot be thrown away in the regular trash can, because they pose a biohazard risk. Biohazardous waste is any material that contains or has been exposed to infectious agents, such as blood, bacteria, viruses, or parasites. Biohazardous waste must be handled and disposed of according to specific safety protocols, such as using autoclaves, incinerators, or biohazard bags. Therefore, after testing tonicity in the lab, the items that have been contaminated with blood cannot be disposed of in the trash can.

Choice A rationale: Movement of water into the blood from the dialysis solution is incorrect because it is not the main goal of dialysis. Dialysis aims to remove excess water and solutes from the blood, not to add more water to it. The dialysis solution is usually isotonic to the blood, which means it has the same osmotic pressure and does not cause water movement.

Choice B rationale: Simple diffusion across a semi-permeable membrane is correct because it is the process of dialysis. Dialysis is the separation of small molecules from large molecules by using a membrane that allows only the small molecules to pass through. The dialysis membrane is semi-permeable, which means it is selective in what it allows to cross. The dialysis solution contains a lower concentration of wastes than the blood, which creates a concentration gradient that drives the diffusion of wastes from the blood to the solution.

Choice C rationale: Active transport across a semi-permeable membrane is incorrect because it is not involved in dialysis. Active transport is the movement of molecules across a membrane against their concentration gradient, which requires energy and transport proteins. Active transport is not necessary for dialysis, since the concentration gradient is favorable for diffusion.

Choice D rationale: Active transport of glucose from the blood to the dialysis solution is incorrect because it is not beneficial for dialysis. Glucose is a vital nutrient for the body, and it should not be removed from the blood. The dialysis solution usually contains glucose to prevent its loss from the blood by diffusion.

Choice E rationale: Facilitated diffusion across a semi-permeable membrane is incorrect because it is not relevant for dialysis. Facilitated diffusion is the passive movement of molecules across a membrane with the help of transport proteins. Facilitated diffusion is not needed for dialysis, since the wastes are small enough to cross the membrane by simple diffusion.