Lecture Notes on Cell Membranes and Transport Mechanisms

This set of flashcards covers key terms and definitions related to the structure and function of cell membranes, transport mechanisms, and concepts related to osmosis and tonicity.

What is the name of the model describing the plasma membrane as a mosaic of proteins floating in a fluid lipid bilayer?

Fluid Mosaic Model

Describe the structure of the Phospholipid Bilayer, including the orientation of hydrophilic and hydrophobic parts.

A double layer of phospholipids with hydrophilic heads facing outward towards water and hydrophobic tails facing inward, away from water.

What property of cell membranes allows only certain substances to pass through while blocking others?

Selective Permeability

What term describes molecules or regions that are 'water-loving' and interact well with water?

Hydrophilic

What term describes molecules or regions that are 'water-fearing' and repel water?

Hydrophobic

How does water move across a selectively permeable membrane from low solute to high solute concentration without energy?

Osmosis

What type of solution has a higher solute concentration than the cell, causing the cell to lose water?

Hypertonic

What type of solution has a lower solute concentration than the cell, causing the cell to gain water?

Hypotonic

What type of solution has the same solute concentration as the cell, resulting in no net water movement?

Isotonic

What process requires energy to move substances across a cell membrane against their concentration gradient?

Active Transport

What is the passive transport of molecules across a membrane using special proteins, allowing substances to move down their concentration gradient?

Facilitated Diffusion

What is the process where a cell takes in material by forming a new vesicle around it?

Endocytosis

What is the process where a cell expels materials through vesicles fusing with the plasma membrane?

Exocytosis

What type of proteins transport substances across a cell membrane by changing shape?

Carrier Proteins

What specific channel protein facilitates the transport of water across cell membranes?

Aquaporin

What is the process by which a cell responds to environmental signals, often involving receptors?

Signal Transduction