Tonicity and Osmoregulation

These flashcards cover key concepts related to tonicity, osmosis, and water potential essential for understanding cellular functions and responses to environmental changes.

What is osmosis?

A type of passive transport in which water molecules diffuse from an area of higher concentration to an area of lower concentration.

What happens to plant cells in hypotonic solutions?

Plant cells gain water and maintain turgor pressure.

Define tonicity.

The ability of an extracellular solution to cause a cell to gain or lose water.

Differentiate between isotonic, hypertonic, and hypotonic solutions.

Isotonic: no net water movement. Hypertonic: cells lose water. Hypotonic: cells gain water.

What is the formula for water potential?

Water potential (Ψ) = solute potential (Ψs) + pressure potential (Ψp).

What occurs to animal cells in hypertonic solutions?

Animal cells lose water and undergo crenation.

What is the relevance of aquaporins in osmosis?

Aquaporins are channel proteins that facilitate the diffusion of water across cell membranes.

What is osmoregulation?

The process by which organisms maintain water balance and control internal solute composition.

What is the equation for calculating solute potential?

Ψs = -iCRT, where i = ionization constant, C = molar concentration, R = pressure constant, T = temperature in Kelvin.

In what environment do plant cells function optimally?

Plant cells function optimally in hypotonic solutions.

What is the outcome of cells placed in isotonic saline solutions?

There is no net movement of water; cells maintain their shape.

What does a hypertonic solution do to a plant cell?

Causes plasmolysis, where the plasma membrane detaches from the cell wall.

Why is turgor pressure important for plants?

It helps maintain structural integrity and supports growth.

What is a contractile vacuole?

An organelle that expels excess water in certain freshwater organisms.

Describe the direction of water movement in regards to water potential.

Water moves from areas of high water potential to areas of low water potential.

How do external environments affect internal cell environments?

They can be hypotonic, hypertonic, or isotonic, affecting water movement and cell health.

What does osmolarity refer to?

The total solute concentration of a solution.

What happens to animal cells in hypotonic solutions?

Animal cells swell and may lyse (burst) due to excessive water uptake.

Define hypertonic solution.

A solution with a higher concentration of solutes compared to the cytosol, causing water to leave the cell.

What occurs to cells in hypertonic solutions?

Cells lose water and may experience plasmolysis or dehydration.

How does temperature affect the pressure potential in water potential calculations?

Temperature is measured in Kelvin, affecting the value of pressure potential.

What is the significance of the ionization constant in solute potential?

It reflects the number of particles formed when a solute dissolves.

What kind of solutions contribute to cell lysis?

Hypotonic solutions can cause animal cells to swell and burst.

Explain water movement in plant cells in a hypertonic solution.

Water moves out, causing the cell to plasmolyze and shrink.

What is a plant's response to hypertonic solutions?

Plants undergo plasmolysis, where the plasma membrane pulls away from the cell wall.

When is a solution considered isotonic relative to a cell?

When the osmolarity of the extracellular fluid is equal to that of the cytosol.

How can you determine the direction of water flow based on solute concentrations?

Water flows from areas of low solute concentration to high solute concentration.

What does it mean for a solution to be hypotonic?

It has a lower concentration of solutes compared to the inside of the cell.

What occurs during plasmolysis in plant cells?

The plasma membrane detaches from the cell wall due to water loss.

In osmosis, what does high osmolarity indicate?

High osmolarity means higher solute concentration and lower water potential.

How does osmolarity relate to tonicity?

Tonicity describes how osmolarity influences the movement of water across cell membranes.

Describe the effect of osmosis on aquatic organisms.

Osmoregulation is crucial for maintaining water and solute balance in aquatic environments.

What role does pressure potential play in water potential?

It reflects the physical pressure exerted on a solution, impacting water flow.

How do cells adapt to hypertonic environments?

Cells may adapt by producing compatible solutes or employing mechanisms to retain water.

State the importance of maintaining osmotic balance in cells.

It is vital for cell function, stability, and overall health.

What is the result of high osmolarity on animal cells?

Animal cells may shrivel and have decreased functionality.

What happens during cytolysis?

Cytolysis refers to the bursting of a cell when it takes in too much water.