The document discusses isotonic, hypotonic, and hypertonic solutions and their effects on cells. An isotonic solution has an equal concentration to a cell, so there is no net movement of water into or out of the cell. A hypotonic solution has a lower concentration than a cell, so water will move into the cell by osmosis, causing it to swell. A hypertonic solution has a higher concentration than a cell, so water will move out of the cell by osmosis, causing it to shrink or crenate.

1. Isotonic , Hypotonic , Hypertonic solutions

2. Isotonic , Hypotonic , Hypertonic solutions iso tonic = a solution of equal concentration to a cell hypo tonic = a solution of lower concentration than a cell (higher water potential) hyper tonic = a solution of higher concentration than a cell (lower water potential) Note: Using these terms always involve comparison between 2 different solutions!

5. Predict the direction of osmosis in the following solutions partially

6. Osmosis in cells

7. How do cells react in isotonic , hypotonic & hypertonic solutions? partially

8. Isotonic solution + cells

9. Hypotonic solution + cells swell -> may burst turgid

10. (only for plant cells!)

11. Turgor pressure

12. Turgidity Maintains shape of soft plant tissues [provides support (water sufficient)/ wilts (lack of water -> control fertilizer input )] Responsible for movement in plants e.g. mimosa -> changes in turgor in small swellings at the base of leaflets e.g. flowers opening in day and closing at night/ bending of petals

13. Hypertonic solution + cells Crenation Plasmolysis

14. Crenation crenation is caused by water movement out of a cell in a hypertonic solution

15. Crenation

16. Plasmolysis (shrinkage of cytoplasm away from cellulose cell wall when plant cells are immersed in a solution of low water potential) Normal plant cells (turgid) Plasmolysed plant cells (flaccid) hypertonic salt solution Plasmolysed cells lend little support to the structure of the plant, indeed this is the very reason why plants wilt if put into salty water

17. - vacuoles decreases in size - cytoplasm shrinks away from the cellulose cell wall

18. Summary

20. Question: What happens when 2 fresh raw eggs (with their shells removed with acid) are placed into a sucrose solution (hypertonic) and distilled water (hypotonic)?

21. Answer: Water enters the egg in water ( endosmosis ) causing it to swell and water leaves the egg in sucrose causing it to shrink ( exosmosis ).

22. Question: Here are typical data from a dialysis tubing experiment. Is the dialysis tubing in a(n): (a) Hypotonic environment (b) Isotonic environment (c) Hypertonic environment