Question

1.Define the terms hypotonic and hypertonic. If I were to give you the salt concentration, for example, inside a cell versus outside a cell, be able to state whether the solution outside the cell is hypotonic or hypertonic to the cell. Also, what is isotonic?

2. Explain turgor, and how this term applies to wilting (think of how a cut flower will wilt out of water)

3. Question about turgor and osmosis – think of a leftover salad. You have salad dressing on the salad, which is typically salty and concentrated so that it is flavorful. Link osmosis and turgor to the fact that salads do not stay fresh very long after they are dressed?

Answer 1

1) Hypertonic solution refers to the solution which has more solute and less water (greater osmotic pressure) than another solution where as in hypotonic solution, reverse is true i.e. hypotonic solution has more water and less solute (lower osmotic pressure) compared to the other solution. In biology, the other solution is usually taken as cell's protoplasm. Hypertonic solution may thus be defined as solution in which solute concentration is higher outside than inside of cell while hypotonic solution is one in which solute concentration is higher inside the cell than outside of it. Also, isotonic cell is the solution in which solute concentration is same inside and outside of the cell.

A solution outside the cell is hypotonic with respect to cell having high salt concentration.

2) Turgor pressure is water pressure inside a plant cells. It is a force exerted by expanding protoplast that pushes plasma membrane against the cell wall and is maintained by osmosis. If a cell is kept in a hypertonic solution, the water inside the cell will start to come out and cause cell to shrink, Cell will lose it's turgor pressure and will become flaccid. This eventually will result in cell losing its rigidity and structure, causing the plant to wilt.