Passive Transport Across the Cell Membrane

These flashcards cover the key concepts of passive transport across the cell membrane, including diffusion, osmosis, types of solutions, and the effects on animal and plant cells.

What are solutes?

Dissolved particles within a solution.

What does concentration refer to?

The amount of solute particles in a given volume of solvent.

What is a concentration gradient?

A difference in concentration across a distance or space.

What does high concentration mean?

A solution with a larger amount of solute compared to another solution.

What does low concentration mean?

A solution with a smaller amount of solute compared to another solution.

What is diffusion?

The movement of particles from an area of high concentration to an area of low concentration.

What is equilibrium in relation to particle movement?

A state where the concentration of particles is equal on both sides of a membrane, resulting in no net movement.

What is simple diffusion?

The movement of small, nonpolar solutes across the cell membrane without energy.

What types of molecules typically undergo simple diffusion?

Small, nonpolar molecules such as oxygen gas (O2) and carbon dioxide (CO2).

What is facilitated diffusion?

The process by which larger or polar/charged solutes cross the membrane with the help of membrane proteins.

What are channel proteins?

Proteins that provide a passageway for large, polar, or charged solutes across the membrane.

What are carrier proteins?

Proteins that bind specifically to solutes and change shape to transport them across the membrane.

How does concentration affect the rate of diffusion?

Higher concentrations increase the rate of diffusion due to more collisions between molecules.

What effect does temperature have on diffusion?

Higher temperatures increase the energy of molecules, resulting in faster diffusion.

How does molecular size affect diffusion?

Larger molecules diffuse more slowly due to increased friction.

What is osmosis?

The process of water diffusing across a membrane.

How does water move during osmosis?

Water moves from areas of high water concentration to areas of low water concentration until equilibrium is reached.

What is a hypotonic solution?

A solution with a higher water concentration and lower solute concentration compared to the cell's internal environment.

What happens when a cell is placed in a hypotonic solution?

Water enters the cell, causing it to swell.

What is turgor pressure?

The pressure of the cytoplasm against the cell wall in plant cells.

What is a hypertonic solution?

A solution with a lower water concentration and higher solute concentration compared to the cell's internal environment.

What happens when a cell is placed in a hypertonic solution?

Water leaves the cell, causing it to shrink.

What happens to animal cells in a hypertonic solution?

Animal cells will shrink and can become crenated (shriveled).

What happens to plant cells in a hypertonic solution?

Plant cells may become plasmolyzed, as the cell membrane pulls away from the cell wall.

What is an isotonic solution?

A solution with equal water and solute concentrations compared to the cell's internal environment.

What occurs with cells in isotonic solutions?

There is no net movement of water, and cells maintain their size.

How do plant cells react in isotonic solutions?

Plant cells do not thrive and may become flaccid due to reduced turgor pressure.