Membrane Structure and Function

These flashcards cover key concepts, definitions, and processes related to membrane structure and function.

What is the Fluid Mosaic Model of the cell membrane?

It describes the cell membrane as a phospholipid bilayer with protein molecules embedded in it, with proteins scattered irregularly.

What are the two types of proteins found in the plasma membrane?

Peripheral proteins and integral proteins.

What is the role of carbohydrate chains on animal cell membranes?

They form the glycocalyx, which protects the cell and plays a role in cell-to-cell recognition.

What determines the fluidity of the plasma membrane?

The types of lipids present in the membrane.

What type of proteins allow for the transport of materials across the plasma membrane?

Channel proteins and carrier proteins.

What is diffusion?

The movement of molecules from an area of higher concentration to an area of lower concentration until equilibrium is reached.

How does osmosis differ from diffusion?

Osmosis specifically refers to the movement of water toward solute molecules that cannot cross the membrane.

What is the definition of a hypotonic solution?

A solution with a lower concentration of solutes than the interior of a cell.

What occurs in a hypertonic solution?

Cells lose water and may undergo crenation or plasmolysis.

What is facilitated diffusion?

A process where special carrier proteins transport specific molecules across the membrane without the use of energy.

What is active transport?

The movement of substances against a concentration gradient, requiring energy, often through carrier proteins.

What is the function of the Sodium-Potassium Pump?

It pumps sodium out of cells and potassium into cells, using ATP for energy.

What is endocytosis?

The process by which cells take in substances by engulfing them in a vesicle.

What is receptor-mediated endocytosis?

A type of pinocytosis where molecules bind to specific receptor molecules on the plasma membrane for transport.

What are anchoring junctions?

Junctions between cells that include adhesion junctions and desmosomes.

What is the extracellular matrix?

A network of proteins and carbohydrates outside of cells that provides structural and biochemical support.

What is the purpose of the plant cell wall?

It provides structure and protection to plant cells.

What are plasmodesmata?

Channels between plant cells that allow for transport and communication.