AP Bio Insta-Review Topic 2.8*: Tonicity & Osmoregulation

Front

What is tonicity?

Back

Tonicity refers to the ability of a surrounding solution to cause a cell to gain or lose water. It is determined by the concentration of solutes in the solution compared to the concentration of solutes inside the cell.

Front

Define isotonic solution.

Back

An isotonic solution has the same solute concentration as another solution, resulting in no net movement of water across the cell membrane.

Front

What happens to a cell in a hypertonic solution?

Back

In a hypertonic solution, the solute concentration outside the cell is higher than inside, causing water to move out of the cell, leading to cell shrinkage.

Front

What is a hypotonic solution?

Back

A hypotonic solution has a lower solute concentration compared to another solution, causing water to move into the cell, which may lead to cell swelling or bursting.

Front

Explain osmoregulation.

Back

Osmoregulation is the process by which organisms regulate the water and solute concentrations in their bodies to maintain homeostasis.

Front

What is water potential?

Back

Water potential is the measure of the potential energy in water, influencing the direction of water movement. It is affected by solute potential and pressure potential.

Front

Calculate the water potential if pressure potential is 0.2 MPa and solute potential is -0.6 MPa.

Back

Water Potential = Pressure Potential + Solute Potential = 0.2 MPa + (-0.6 MPa) = -0.4 MPa.

Front

What does a higher solute concentration indicate about a solution?

Back

A higher solute concentration indicates that the solution is hypertonic, which can lead to water moving out of cells placed in that solution.

Front

What is the ionization constant of sodium chloride (NaCl)?

Back

The ionization constant of sodium chloride is 2, as it dissociates into two ions: Na+ and Cl-.

Front

Describe the movement of water in an isotonic environment.

Back

In an isotonic environment, water moves equally into and out of the cell, maintaining cell size and shape.