1. The cell membrane is selectively permeable.
2. Small, nonpolar molecules like oxygen and carbon dioxide can diffuse across the cell membrane easily.
3. If a cell doesn’t have enough O₂ to make ATP, it will die.
4. In active transport, substances move from low to high concentration.
5. If CO₂ diffuses out of the cell, the cell would require more time to maintain equilibrium and would have to work harder to produce ATP.
6. Diffusion: small, nonpolar molecules; Osmosis: water; Active Transport: large or charged molecules.
7. Passive transport requires no energy; active transport requires energy (ATP).
8. Endocytosis: engulfing material into the cell; Exocytosis: expelling material out of the cell.
9. The process by which cells use energy to move materials across the cell membrane is called active transport.
10. The two types of endocytosis are phagocytosis and pinocytosis.
11. Phagocytosis is the process where a cell engulfs large particles or other cells.
12. Pinocytosis is the process where a cell takes in fluids and dissolved solutes.
13. Exocytosis is the process where vesicles fuse with the plasma membrane to release their contents outside the cell.
14. A cell that needs to take in large amounts of material would likely use phagocytosis.
15. A cell that needs to release waste products or secretions would likely use exocytosis.
16. When a cell uses active transport to move molecules against their concentration gradient, it requires energy in the form of ATP.
17. The sodium-potassium pump is an example of active transport that moves Na⁺ out of the cell and K⁺ into the cell.
18. If a cell’s membrane becomes too rigid, it may not be able to perform endocytosis or exocytosis effectively.
19. If a cell’s membrane becomes too fluid, it may lose its selective permeability and allow unwanted substances to enter.
20. The cell membrane maintains homeostasis by regulating what enters and exits the cell.
Parent Tip: Review the logic above to help your child master the concept of cellular transport and the cell cycle worksheet.
