bio 2.8

These flashcards cover the concepts of osmosis, tonicity, and osmoregulation, helping to prepare for understanding the movement of water and solutes across cell membranes.

What is osmosis?

The diffusion of free water across a selectively permeable membrane.

What role do aquaporins play in water movement?

Aquaporins facilitate the transport of large quantities of water across the cell membrane.

Define osmolarity.

The total solute concentration in a solution.

What is tonicity?

The measurement of the relative concentrations of solute between two solutions inside and outside of a cell.

What occurs in a hypertonic environment?

The environment has more solute and less water than the inside of the cell, causing water to leave the cell.

What happens to a cell in an isotonic environment?

There is equal movement of water in and out of the cell, resulting in no net movement of water.

What is plasmolysis?

The process that occurs when water leaves a plant cell due to environmental hypertonicity, causing the cell to shrink.

How does osmoregulation function in plant cells?

It maintains water balance and controls internal solute composition.

What is turgor pressure?

The pressure exerted by the cell wall against the cytoplasm due to water entering the vacuoles via osmosis.

What happens to animal cells in a hypotonic environment?

They risk lysis, which means they could burst due to excess water intake.

How does a freshwater paramecium maintain homeostasis in a hypotonic environment?

It collects excess water in the contractile vacuole and pumps it out.

What happens to a paramecium placed in saltwater?

Water would diffuse out of the paramecium, risking the cell shriveling.

What is the relationship between osmolarity and water movement?

Water moves by osmosis from areas of low osmolarity to areas of high osmolarity.

How is growth and homeostasis maintained in cells?

Through the constant movement of molecules across the membrane.

What is the optimum state for a plant cell?

Turgidity, where the cell is firm and fully inflated due to water.