During osmosis, individual molecules move:A)Toward lower concentrationsB)Toward lower osmotic pressureC)All directions with equal probabilityD)Toward higher concentrationsQ2. When the SimCell membrane in the Cell-O-Scope simulator jiggled back and forth, this was due to:A)Pressure against the membraneB)Osmosis causing molecules to flow across the membraneC)The membrane not being at equilibriumD)None of the aboveQ3. Placing blood cells into a solution that is hypertonic to the cells will cause the osmotic pressure of the cells to:A)IncreaseB)DecreaseC)Neither increase nor decreaseQ4. Placing blood cells into a solution that is isotonic to the cells will cause the osmotic pressure of the cells to:A)IncreaseB)DecreaseC)Neither increase nor decreaseQ5. According to the rules of osmosis, a system will reach a state of equilibrium when there are equal numbers of __ molecules on both sides of a water-permeable membrane.A)soluteB)solventC)waterD)none of the aboveQ6. A SimCell with a water-permeable membrane that contains 20 hemoglobin molecules and 480 water molecules is placed into an extracellular fluid that contains 20 dextrose molecules and 480 water molecules. Which of the following should happen?A)More water molecules will flow from the SimCell into the extracellular fluid than from the extracellular fluid into the SimCell.B)More water molecules will flow from the extracellular fluid into the SimCell than from the SimCell into the extracellular fluid.C)There will be no movement of water molecules across the membrane.D)Water molecules will move back and forth equally across the membrane.Q7. A SimCell with a water-permeable membrane that contains 20 hemoglobin molecules and 480 water molecules is placed in an extracellular fluid that contains 40 dextrose molecules and 960 water molecules. Which of the following should happen?A)More water molecules will flow from the SimCell into the extracellular fluid than from the extracellular fluid into the SimCell.B)More water molecules will flow from the extracellular fluid into the SimCell than from the SimCell into the extracellular fluid.C)There will be no movement of water molecules across the membrane.D)Water molecules will move back and forth equally across the membrane.Q8. A SimCell with a water-permeable membrane that contains 50 dextrose molecules, 25 glucose molecules, 25 hemoglobin molecules and 900 water molecules is placed in an extracellular fluid that is one part solute to 15 parts water (its solute-to-solvent ratio is 1:15). Which of the following should happen?A)More water molecules will flow from the SimCell into the extracellular fluid than from the extracellular fluid into the SimCell.B)More water molecules will flow from the extracellular fluid into the SimCell than from the SimCell into the extracellular fluid.C)There will be no movement of water molecules across the membrane.D)Water molecules will move back and forth equally across the membrane.Q9. A SimCell has a special membrane that is permeable to alcohol but not to water. This SimCell contains 20% alcohol and 80% water and is placed in a solution containing 40% alcohol and 60% water. What will happen to the cell?A)It will expand due to net movement of water into the cell.B)It will expand due to net movement of alcohol into the cell.C)It will contract due to net movement of water out of the cell.D)It will contract due to net movement of alcohol out of the cell.Q10. Fish that live in saltwater and fish that live in freshwater both have water balance challenges that deal with osmosis. What is the best characterization of the challenges for each, based on your investigations in this lab?A)Both types of fish must constantly get rid of excess water.B)Freshwater fish must get rid of excess water and saltwater fish must retain the water they have.C)Freshwater fish must retain the water they have and saltwater fish must get rid of excess water.D)Both kinds of fish must retain as much water as they can.
The Correct Answer and Explanation is :
Let’s address each question in detail:
Q1. During osmosis, individual molecules move:
Answer: D) Toward higher concentrations
Explanation: Osmosis is the passive movement of water molecules through a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration. This movement continues until equilibrium is reached, where the concentration of solute is equal on both sides of the membrane.
Q2. When the SimCell membrane in the Cell-O-Scope simulator jiggled back and forth, this was due to:
Answer: C) The membrane not being at equilibrium
Explanation: The jiggling of the membrane indicates that the system has not yet reached equilibrium. In osmosis, water molecules move across the membrane until the concentrations of solute are equal on both sides. Until this equilibrium is achieved, the membrane will exhibit movement due to the ongoing process of osmosis.
Q3. Placing blood cells into a solution that is hypertonic to the cells will cause the osmotic pressure of the cells to:
Answer: B) Decrease
Explanation: A hypertonic solution has a higher concentration of solutes compared to the inside of the cell. When blood cells are placed in such a solution, water moves out of the cells to balance the solute concentrations, leading to cell shrinkage. As water leaves, the osmotic pressure inside the cells decreases.
Q4. Placing blood cells into a solution that is isotonic to the cells will cause the osmotic pressure of the cells to:
Answer: C) Neither increase nor decrease
Explanation: An isotonic solution has the same concentration of solutes as the inside of the cell. In this scenario, there is no net movement of water into or out of the cell, so the osmotic pressure remains unchanged.
Q5. According to the rules of osmosis, a system will reach a state of equilibrium when there are equal numbers of __ molecules on both sides of a water-permeable membrane.
Answer: C) Water
Explanation: Osmosis involves the movement of water molecules across a semipermeable membrane. Equilibrium is achieved when the concentration of water molecules is equal on both sides of the membrane, not necessarily when the number of solute molecules is equal.
Q6. A SimCell with a water-permeable membrane that contains 20 hemoglobin molecules and 480 water molecules is placed into an extracellular fluid that contains 20 dextrose molecules and 480 water molecules. Which of the following should happen?
Answer: B) More water molecules will flow from the extracellular fluid into the SimCell than from the SimCell into the extracellular fluid.
Explanation: In this scenario, the SimCell contains hemoglobin molecules, which are large and cannot pass through the membrane, while the extracellular fluid contains dextrose molecules, which are small and can pass through. This creates a concentration gradient where the extracellular fluid has a higher concentration of permeable solutes (dextrose) compared to the SimCell. To balance the concentrations, water will move into the SimCell, leading to cell expansion.
Q7. A SimCell with a water-permeable membrane that contains 20 hemoglobin molecules and 480 water molecules is placed in an extracellular fluid that contains 40 dextrose molecules and 960 water molecules. Which of the following should happen?
Answer: B) More water molecules will flow from the extracellular fluid into the SimCell than from the SimCell into the extracellular fluid.
Explanation: The extracellular fluid has a higher concentration of permeable solutes (dextrose) compared to the SimCell. To balance the concentrations, water will move into the SimCell, leading to cell expansion.
Q8. A SimCell with a water-permeable membrane that contains 50 dextrose molecules, 25 glucose molecules, 25 hemoglobin molecules, and 900 water molecules is placed in an extracellular fluid that is one part solute to 15 parts water (its solute-to-solvent ratio is 1:15). Which of the following should happen?
Answer: B) More water molecules will flow from the extracellular fluid into the SimCell than from the SimCell into the extracellular fluid.
Explanation: The extracellular fluid has a higher concentration of permeable solutes compared to the SimCell. To balance the concentrations, water will move into the SimCell, leading to cell expansion.
Q9. A SimCell has a special membrane that is permeable to alcohol but not to water. This SimCell contains 20% alcohol and 80% water and is placed in a solution containing 40% alcohol and 60% water. What will happen to the cell?
Answer: B) It will expand due to net movement of alcohol into the cell.
Explanation: Since the membrane is permeable to alcohol but not to water, alcohol molecules will move into the SimCell from the surrounding solution to balance the concentrations. This influx of alcohol will cause the cell to expand.
Q10. Fish that live in saltwater and fish that live in freshwater both have water balance challenges that deal with osmosis. What is the best characterization of the challenges for each, based on your investigations in this lab?
Answer: B) Freshwater fish must get rid of excess water and saltwater fish must retain the water they have.
Explanation: Freshwater fish live in an environment where the surrounding water has a lower concentration of solutes compared to their bodies. This causes water to enter their bodies, and they must excrete the excess to maintain osmotic balance. Conversely, saltwater fish live in an environment where the surrounding water has a higher concentration of solutes. They must retain water to prevent dehydration.
For a visual explanation of osmosis and related concepts, you might find the following video helpful: