Question

part c: decide whether each statement is true or false.

1. __ active transport requires atp to move substances against a concentration gradient.
2. __ the cell membrane is selectively permeable, allowing all molecules to pass through.
3. __ a hypertonic solution causes water to move into a cell, making it swell.
4. __ endocytosis is a form of passive transport.
5. __ facilitated diffusion requires a transport protein to help move molecules across the membrane.
6. __ in an isotonic solution, the concentration of solutes inside and outside the cell is equal.
7. __ hypotonic solutions will cause animal cells to lose water and shrink.

part d: answer the following questions using complete sentences.

1. what is the difference between facilitated diffusion and simple diffusion?
2. what molecules can easily diffuse across the cell membrane?
3. what molecules cannot easily diffuse across the cell membrane?
4. why would a dehydrated individual need to receive a saline iv instead of pure water? (explain your answer in terms of cell transport and osmosis.)
5. create an illustration that showcases what would happen to a freshwater fish if it was placed in a saltwater environment. use arrows in your illustration to indicate water flow.

Explanation:

Part C:

• 7. Active transport indeed uses ATP to move substances against a concentration gradient, so it's True.
• 8. The cell - membrane is selectively permeable, allowing only certain molecules to pass through, not all, so it's False.
• 9. A hypertonic solution causes water to move out of a cell, making it shrink, not swell, so it's False.
• 10. Endocytosis is a form of active transport, not passive transport, so it's False.
• 11. Facilitated diffusion requires a transport protein to move molecules across the membrane, so it's True.
• 12. In an isotonic solution, the solute concentration inside and outside the cell is equal, so it's True.
• 13. Hypotonic solutions cause animal cells to gain water and swell, not lose water and shrink, so it's False.

Part D:

• 14. Simple diffusion is the movement of small, non - polar molecules directly through the lipid bilayer of the cell membrane down their concentration gradient, while facilitated diffusion uses transport proteins (carrier or channel proteins) to move larger or polar molecules down their concentration gradient.
• 15. Small, non - polar molecules like oxygen ($O_2$), carbon dioxide ($CO_2$), and small hydrophobic molecules can easily diffuse across the cell membrane.
• 16. Large polar molecules (e.g., glucose), ions (e.g., $Na^+$, $K^+$), and charged molecules cannot easily diffuse across the cell membrane.
• 17. A dehydrated individual needs a saline IV instead of pure water because pure water would be hypotonic relative to the cells. This could cause water to rush into the cells by osmosis, potentially leading to cell swelling and lysis. Saline IV has a similar solute concentration to the body's fluids (isotonic), preventing excessive water movement into the cells and maintaining cell integrity.
• 18. If a freshwater fish is placed in a saltwater environment, the saltwater is hypertonic relative to the fish's cells. Water will move out of the fish's cells by osmosis. In the illustration, arrows should point from inside the fish (representing cells) to the outside (the saltwater environment) to indicate water flow.

Answer:

Part C:

1. True
2. False
3. False
4. False
5. True
6. True
7. False

Part D:

1. Simple diffusion is the movement of small, non - polar molecules directly through the lipid bilayer, while facilitated diffusion uses transport proteins to move larger or polar molecules.
2. Small, non - polar molecules such as oxygen, carbon dioxide, and small hydrophobic molecules.
3. Large polar molecules, ions, and charged molecules.
4. Saline IV is isotonic and prevents cell swelling and lysis that could occur with pure water (hypotonic), which would cause excessive water influx into cells by osmosis.
5. Arrows should point from inside the fish (cells) to the outside (saltwater environment) to show water moving out of the fish's cells due to the hypertonic saltwater.