1.4: Membrane Transport (IB Biology)

Front

What is the fluid mosaic model of cell membranes?

Back

The fluid mosaic model describes the structure of cell membranes as a mosaic of various components (phospholipids, proteins, cholesterol) that move fluidly within the layer, allowing for flexibility and functionality.

Front

What is endocytosis?

Back

Endocytosis is the process by which cells internalize substances from their external environment by engulfing them in a membrane-bound vesicle.

Front

What is exocytosis?

Back

Exocytosis is the process by which cells expel materials in vesicles that fuse with the plasma membrane, releasing their contents outside the cell.

Front

What is facilitated diffusion?

Back

Facilitated diffusion is a passive transport process that allows substances to cross membranes with the assistance of special proteins, such as channel or carrier proteins.

Front

What role do channel proteins play in membrane transport?

Back

Channel proteins provide passageways for specific ions or molecules to cross the cell membrane, facilitating transport without the use of energy.

Front

What is osmosis?

Back

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

Front

What happens to a cell in a hypertonic solution?

Back

In a hypertonic solution, water moves out of the cell, causing it to shrink or crenate due to loss of water.

Front

What is the difference between active and passive transport?

Back

Active transport requires energy (ATP) to move substances against their concentration gradient, while passive transport does not require energy and moves substances along their concentration gradient.

Front

What is the role of the Golgi apparatus in protein transport?

Back

The Golgi apparatus modifies, sorts, and packages proteins received from the rough endoplasmic reticulum for transport to their final destinations.

Front

What is a selectively permeable membrane?

Back

A selectively permeable membrane allows certain molecules or ions to pass through while restricting others, maintaining the internal environment of the cell.