BIOL1001 Quiz 3: Membrane Structure and Function

Vocabulary practice flashcards covering cellular membrane components, transport mechanisms, tonicity, and osmoregulation from Biology Lecture 3.

ATP

An energy molecule that possesses $3$ phosphate groups.

Carrier Proteins

Membrane proteins that typically transport specific, larger, or uncharged polar molecules such as glucose and amino acids across biological membranes.

Channel Proteins

Membrane proteins that mediate passive transport by providing hydrophilic corridors for specific molecules or ions to cross the membrane down their concentration gradient without requiring energy input.

Functions of Membrane Proteins

Roles performed by membrane proteins including transport across the membrane, cell-cell recognition, intercellular joining, enzymatic activity, and signal transduction (excluding cell division).

Osmosis

The net movement or diffusion of water molecules across a selectively permeable membrane from a region of lower solute concentration to a region of higher solute concentration.

Phospholipids

Amphipathic molecules possessing both hydrophobic (water-repelling) fatty acid tails and hydrophilic (water-attracting) phosphate heads, arranged in two layers in the plasma membrane.

Amphipathic

A chemical property describing molecules like phospholipids that contain both hydrophobic and hydrophilic regions.

Hypotonic Solution

The ideal environmental solution for plant cells, causing water to enter until the cell wall exerts turgor pressure back against the cell, keeping it turgid (firm and healthy).

Isotonic Solution

The ideal environmental solution for animal cells, where solute concentrations inside and outside are equal, resulting in no net water movement and preventing lysis or crenation.

Turgid

The firm and healthy state of a plant cell that occurs when water enters the cell in a hypotonic solution, providing structural support for the plant.

Plasmolysis

The cellular shrinkage phenomenon that occurs when a plant cell is placed into a hypertonic solution.

Flaccid

The state of a plant cell when it is placed in an isotonic solution.

Osmoregulation

The process by which organisms control and maintain the balance of water and solute concentrations across membranes to preserve homeostatic fluid balance.

Plasma Membrane

A selectively permeable cellular boundary composed of two layers of lipids.