Cell Permeability & Transport

What is the definition of permeability in the context of cell models?

The ability of a membrane to allow substances to pass through.

What do we understand by selective permeability?

Some molecules can pass through the membrane, while others cannot.

What is tonicity?

The relative solute concentration of two solutions.

What is the driving force in transport processes?

The factor causing movement, such as concentration gradient, pressure, or ATP.

What does a hypotonic solution do to red blood cells?

Causes the cells to swell and become turgid.

What effect does a hypertonic solution have on red blood cells?

Causes the cells to shrink, leading to plasmolysis.

What happens to red blood cells in an isotonic solution?

There is no visible change to the cells.

What does Benedict’s solution test for?

Tests for glucose, changing color from blue to orange when heated.

What substance does iodine (IKI) test for?

Tests for starch, changing from yellow-brown to blue-black.

How do artificial cell models demonstrate selective permeability?

They have microscopic pores that allow smaller molecules to pass while retaining larger ones.

What is the definition of permeability in the context of cell models?

The ability of a membrane to allow substances to pass through.

What do we understand by selective permeability?

Some molecules can pass through the membrane, while others cannot.

What is tonicity?

The relative solute concentration of two solutions.

What is the driving force in transport processes?

The factor causing movement, such as concentration gradient, pressure, or ATP.

What does a hypotonic solution do to red blood cells?

Causes the cells to swell and become turgid.

What effect does a hypertonic solution have on red blood cells?

Causes the cells to shrink, leading to plasmolysis.

What happens to red blood cells in an isotonic solution?

There is no visible change to the cells.

What does Benedict’s solution test for?

Tests for glucose, changing color from blue to orange when heated.

What substance does iodine (IKI) test for?

Tests for starch, changing from yellow-brown to blue-black.

How do artificial cell models demonstrate selective permeability?

They have microscopic pores that allow smaller molecules to pass while retaining larger ones.

What is the key difference between passive and active transport?

Passive transport does not require energy (e.g., diffusion, osmosis), while active transport requires energy (ATP) to move substances against their concentration gradient.

Define diffusion in the context of membrane transport.

Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration.

What is osmosis?

Osmosis is the diffusion of water across a selectively permeable membrane from an area of higher water concentration to an area of lower water concentration.

Why do plant cells not burst in a hypotonic solution, unlike animal red blood cells?

Plant cells have a rigid cell wall that provides structural support and prevents over-expansion, maintaining turgor pressure, whereas animal cells lack a cell wall and will lyse.