General Biology 1: Cell Transport Systems

Vocabulary flashcards covering the key terms and concepts of cell transport systems, including passive transport, active transport, and bulk transport based on General Biology 1.

Fluid Mosaic Model

A cell membrane model proposed in 1972, commonly attributed to Seymour J. Singer and Garth L. Nicolson.

Hydrophilic Head

The polar part of a phospholipid, composed of phosphoric acid (phosphorylated alcohol) and glycerol, which interacts with water.

Hydrophobic Tail

The non-polar part of a phospholipid consisting of two fatty acid chains with kinks that repel water.

Diffusion

The mixing of materials by their own random motion from an area of high concentration to an area of low concentration along a concentration gradient.

Osmosis

The diffusion of $H_2O$ molecules through a membrane from an area of high concentration to low concentration.

Osmotic Pressure

The pressure caused by water molecules during osmosis.

Hypotonic Solution

A solution with higher water potential than inside the cell, causing water to move into the cell, making animal cells burst and plant cells become turgid.

Hypertonic Solution

A solution with lower water potential than inside the cell, causing water to move out of the cell, making animal cells shrink and plant cells become plasmolysed.

Plasmolysis

The process in plant cells placed in a hypertonic solution where the cell shrinks and the protoplast pulls away from the cell wall.

Active Transport

The movement of molecules via membrane proteins in one direction against the concentration gradient, requiring energy (ATP) from the cell.

Sodium / Potassium Pump

An active transport system that pumps $2$ $K^+$ (potassium) ions into the cell and $3$ $Na^+$ (sodium) ions out of the cell using energy from ATP in a 6-step process.

Endocytosis

A bulk transport process where large particles enter the cell as the membrane actively surrounds and engulfs particles or fluid to form a vesicle.

Phagocytosis

A type of endocytosis known as 'cell eating' that involves the engulfment of large particles.

Pinocytosis

A type of endocytosis known as 'cell drinking' that involves the engulfment of liquids.

Exocytosis

A bulk transport process where large particles exit the cell as a vesicle moves to and merges with the plasma membrane, rupturing outwards to release its contents.

Receptor-Mediated Endocytosis

A process where ligands bind to specific receptors on coated pits on the cell surface, such as the process human cells use to take in cholesterol.