Final answer:
In this scenario, water molecules will move through osmosis, resulting in changes in concentration inside and outside the cell.
Step-by-step explanation:
Animal cells are permeable to water and urea but not to sucrose. In this scenario, the initial concentrations of sucrose and urea inside and outside the cell are:
Inside: 10 molecules of sucrose and 10 molecules of urea
Outside: 20 molecules of sucrose and 10 molecules of urea
As osmosis occurs, water molecules will move from an area of lower solute concentration (higher water concentration) to an area of higher solute concentration (lower water concentration). Since the sucrose molecules cannot pass through the cell membrane, there will be no net movement of sucrose. However, since the urea molecules can pass through the cell membrane, there will be equalization of urea concentrations inside and outside the cell.
Therefore, after the system reaches equilibrium via osmosis, the concentrations inside and outside the cell will be:
Inside: 20 molecules of sucrose and 10 molecules of urea
Outside: 20 molecules of sucrose and 10 molecules of urea