Question

Why? How do water morcules move in and out of cells counts for over 70% of the human body. If water levels are not regulated and maintained in an is the consequences can be disastrous. Cells and tissues may well, blood cells burst, or the brain muy expand so much it pushes on the skull, leading to brain damage and death. So what exactly is the process that allows organisms to regulate and maintain their water content? Model 1 - Movement of Water In and Out of Cells 0 0 O Super molecules (solute) + Water molecules (solvent) EEE Selectively permeabile membrane +0+0+0² 1. A solution consists of a solute and a solvent mixed together. For the solution in Model 1 identify and provide the symbol for the 4. solute & solvent. Circle the correct word below to indicate the change in the concentration of the sugar solution on each side of the membrane as water molecules move. 4. The solution inside the cell will become (more/les) concentrated with the net movement of 2. Consider the size of the sugar and water molecules in Model 1. Which molecules in the diagram in Model 1 are able to move through the selectively permeable membrane! The solution outside the cell will become more/les concen water. Outside the Cell 3. Complete the table below by counting the molecules in Model 1. Inside the Cell Number of sugar molecules Number of water molecules Ratio of water to sugar 4. Which solution in Model 1 is more concentrated the solution inside the cell or outside of the cell? Explain your answer in terms of the ratio of solute to solvent particles. 5. Consider the arrows indicating movement of water across the membrane 4. In which direction are water molecules moving into or out of the cell? k Are more water molecules moving into or out of the cell? c. Is the net direction of water movement into or out of the cell?

Answer 1

1. The water are the solvent units (b) as they seem to be travelling across the semipermeable membrene and the bigger round particles i,e sugar molecules are the solute units (a).

2. The water molecules are the ones which can move across the semi permeable membrene.

3. No. of sugar molecules outside the cell : 15

No. of water molecules outside the cell : 15

Ratio of number of water to sugar: 15/15= 1

No. of sugar molecules inside the cell : 6

No. of water molecules inside the cell : 24

Ratio of number of water to sugar: 24/6= 4

4. As we can see the Water to Sugar ratio is more inside the cell than outside that is there are more water molecules wrt the number of sugar molecules inside the cell, hence the solution is more diluted. Thus we can sday that the solution outsiode the cell ismore concentrated.

5. a. Water molecules are moving both into and out of the cell as indicated by the arrows.

b. More water molecules are moving out of the cell

c. The net direction of movement of water is out of the cell.