CELS191 Lecture 3: Plasma Membrane & Organelles

Vocabulary flashcards from the CELS191 lecture focusing on plasma membranes and organelles.

Plasma Membrane

A semi-permeable barrier that separates the cell from the external environment and controls the movement of substances in and out of the cell.

Phospholipid Bilayer

A double layer of phospholipids that makes up the plasma membrane, providing structural integrity and a barrier to most water-soluble substances.

Membrane Proteins

Proteins embedded in the plasma membrane that perform various functions such as transport, signal transduction, and cell recognition.

Passive Transport

Movement of substances across a membrane without the use of energy, typically down their concentration gradient.

Active Transport

The movement of substances against their concentration gradient, requiring energy (ATP) to facilitate the process.

Co-Transport

Indirect active transport where the movement of one substance down its concentration gradient powers the movement of another substance against its gradient.

Signal Transduction

The process by which cells communicate external signals to initiate a cellular response through membrane proteins.

Facilitated Diffusion

A type of passive transport that relies on membrane proteins to help move hydrophilic molecules across the plasma membrane.

Aquaporins

Specialized channel proteins that facilitate the transport of water across the plasma membrane.

Osmoregulation

The process by which cells regulate the concentration of water and solute to maintain equilibrium.

Endoplasmic Reticulum (ER)

An organelle that synthesizes proteins and membranes, with rough ER associated with ribosomes and smooth ER lacking ribosomes.

Golgi Apparatus

An organelle involved in modifying, sorting, and packaging proteins and lipids for secretion or delivery to other organelles.

Mitochondrion

An organelle known as the powerhouse of the cell, responsible for producing ATP through cellular respiration.

Nucleus

The membrane-bound organelle that contains the cell's genetic material and regulates gene expression.

Cholesterol

A steroid that stabilizes the fluidity of the plasma membrane by preventing tight packing of phospholipids.

Saturation

Refers to the degree of fatty acid saturation in phospholipids, affecting membrane fluidity; saturated fatty acids are more tightly packed than unsaturated.

Intercellular Joining

Connections formed by membrane proteins that enable cells to adhere to one another and form tissues.

Cell Recognition

The process by which cells identify and communicate with one another, often involving glycoproteins.

Cytoskeleton

A network of protein filaments that provide structural support and shape to the cell, and facilitate movement.

Concentration Gradient

A difference in the concentration of a substance across a space, influencing the direction of diffusion.