Match the situation with the result. Write the letter of the correct answer on the line at the left. Situation Cells are in an isotonic solution. Cells are in a hypertonic solution. Cells are in a hypotonic solution. Result The cells lose water. The cells gain water. The cells stay the same. In the table below, draw how each type of cell will look after being placed in a hypertonic solution. Appearance of Cells in a Hypertonic Solution Animal Cells Plant Cells Passive Transport Diffusion is the movement of particles from an area of high concentration to an area of low concentration. Osmosis is the diffusion of water through a selectively permeable membrane. Study the beakers at the right. The arrows between beakers tell you what process is occurring. In the beakers on the right, draw the result of the described process. Draw changes in water levels. Draw changes in the number of solute particles. Remember to draw on both sides of the membrane. Look at the top left beaker. What would happen if the membrane did not allow water or solute particles to pass through it? Label each diagram as either facilitated diffusion or active transport. Facilitated diffusion takes place when a substance diffuses across the cell membrane through a protein channel. Active transport takes place when the cell uses energy to carry a substance across the cell membrane against a concentration difference. Answer the questions by circling the correct answer. Which process can move molecules from a lower concentration solution on one side of the membrane to a higher concentration solution on the other side? active transport facilitated diffusion
Which molecule(s) will move across the membrane and in which net direction(s)? Notice that the levels of liquid in both A and B are equal. Do you think they will appear this way when the system reaches equilibrium? Explain. Three funnels containing three different starch solutions were placed for 24 hours into a beaker that contained a starch solution of UNKNOWN concentration. The end of each funnel was covered by a selectively permeable membrane allowing only water to pass across the membrane. Based on the results, what is the concentration of the unknown solution? How can you tell? Flasks X, Y, and Z contain solutions with different concentrations of the solute NaCl. Flask X has 0.5% NaCl, flask Y has 0.9% NaCl, and flask Z has 1.5% NaCl. Red blood cells (0.9% NaCl) will be placed into each flask. Predict what will happen when water crosses the red blood cell membrane. Predict what will happen to the red blood cells in flask X (draw a diagram). Predict what will happen to the red blood cells in flask Y (draw a diagram). Predict what will happen to the red blood cells in flask Z (draw a diagram). Study the diagrams of the beakers to the right, noting the concentrations of various substances in the beakers and in the cellulose bags. Water molecules can pass through the cellulose, but starch cannot pass through. Draw arrows in the diagrams to show the direction in which water will move.
Mix the blood in a salty solution to cause the RBC’s to lyse. Mix the blood in an isotonic solution and allow the WBCs to float to the top. Mix the blood with a dye that stains the proteins in the cytoplasm. Mix the blood with a hypotonic solution, which will cause the RBCs to lyse. Mix the blood with a hypertonic solution, which will cause the RBCs to lyse. Activities in the human body are represented in the diagram to right. Which would be appropriate for the diagram? Rate of excretion varies in response to amount of water taken in Feedback mechanisms help to maintain homeostasis Respiratory rate responds to an increase in muscle activity The nervous system responds to changes in blood sugar levels