Bacteria living in a freshwater stream that are moved to salty seawater would most likely:

• A. remain unaffected due to their cell wall
• B. begin to reproduce more rapidly
• C. lose water and undergo plasmolysis
• D. gain water and swell

Answer: (C)

Verified step by step guidance

1. Understand the concept of osmosis, which is the movement of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration.
2. Recognize that freshwater bacteria are adapted to an environment with low solute concentration outside their cells, so their internal environment has relatively higher solute concentration compared to freshwater.
3. When these bacteria are moved to salty seawater, the external environment now has a higher solute concentration than the inside of the bacterial cells.
4. Due to osmosis, water will move out of the bacterial cells into the salty seawater to balance the solute concentrations, causing the cells to lose water.
5. As a result of water loss, the bacterial cells will undergo plasmolysis, where the cell membrane pulls away from the cell wall, leading to cell shrinkage and potential damage.