Bio-Pac 03: Objective 04, 06 and 07 Flashcards
Objective 4. Explain why selectively permeable is necessary for homeostasis within a cell.
Selectively permeable is necessary for homeostasis, or for a cell to live, because it will allow things to pass through the cell that are necessary for the cell to live. You don’t want your cell to be permeable of impermeable, because if it was permeable, the things could pass freely in and out of the cell while some things need to stay in the cell and other things need to stay out; if your cell was impermeable, it would not allow things to go in or out of the cell, while waste needs to go out, and other substances need to come into the cell. Having the plasma membrane being selectively permeable is necessary for homeostasis, because it maintains a balance by controlling materials that enter and leave by keeping the internal concentration balanced and allowing waste materials to leave, and it will let materials to pass in and out when the concentration of the external environment changes, so the internal concentration is the right concentration for the cell.
Objective 6. Design a chart that compares plant and animal cells in different osmotic systems.
ISOTONIC SYSTEM
Plant Cell
• Concentration of water inside and outside of the cell is the same.
• Water moves in and out of the cell at the same rate.
• No stress on cell.
• Osmosis does not occur in cell, but the cell is in dynamic equilibrium.
• Cells will have normal shape.
Animal Cell
• Concentration of water inside and outside of the cell is the same.
• Water moves in and out of the cell at the same rate.
• No stress on cell.
• Osmosis does not occur in cell, but the cell is in dynamic equilibrium.
• Cells will have normal shape.
HYPOTONIC SOLUTION
Plant Cell
• Less concentration of solute outside of cell therefore a greater concentration of water outside of the cell. Therefore the water will move into the cell.
• The turgor pressure will increase, and cause the plasma membrane to push against the cell wall, making the plant stiff. The organelles will slowly die from this.
Animal Cell
• Less concentration of solute outside of cell therefore a greater concentration of water outside of the cell. Therefore the water will move into the cell.
• The turgor pressure will increase and cause cytolysis to occur only in plant cells. Because there is no cell wall the cell will swell from the water coming in and then burst.
HYPERTONIC SOLUTION
Plant Cell
• Greater concentration of solutes outside of the cell therefore a greater concentration of water inside the cell. Therefore the water will move out of the cell.
• Plasmolysis will occur-when a plant or animal cell loses too much water.
• The plasma membrane pulls away from the cell wall.
Animal Cell
• Greater concentration of solutes outside of the cell therefore a greater concentration of water inside the cell. Therefore the water will move out of the cell.
• Plasmolysis will occur-when a plant or animal cell loses too much water.
• The cell will shrink in size.
Objective 7. Differentiate between endocytosis and exocytosis.
Endocytosis and Exocytosis are reverse processes of active transport. Endocytosis is a process that will take in large molecules, groups of molecules, or whole cells by making a cell surround and take in material from its environment, this material does not go through the membrane. This material is engulfed and enclosed by a portion of the cell’s plasma membrane, and then that portion will break away and the resulting vacuole with its contents will then move to the inside of the cell. Exocytosis is the reverse active transport process of endocytosis. Cells will use the exocytosis process to expel waste, such as indigestible particles, and to secrete substances produced by the cell, such as hormones, from the interior of the to the exterior environment.
