Cell Biology and Membrane Transport Flashcards

Vocabulary flashcards covering cell organelles, membrane structure, cell transport mechanisms, osmoregulation, and cell compartmentalization based on lecture notes.

Ribosome

Tiny cellular structures made of ribosomal RNA and proteins that build proteins for the cell.

Rough Endoplasmic Reticulum

Flattened membrane-bound organelle in eukaryotic cells with enclosed sacs studded with ribosomes, functioning to synthesize proteins for export outside the cell.

Smooth Endoplasmic Reticulum

Network of tubes that lacks ribosomes on its surface, functioning to make fats, phospholipids, and steroids, as well as handle detoxification.

Golgi Apparatus

A series of flattened membrane-bound sacs found in eukaryotic cells, functioning in the correct folding and chemical modification of newly synthesized proteins.

Lysosome

Membrane-enclosed sacs found in some eukaryotic cells that contain hydrolytic enzymes and function to digest a variety of materials.

Vacuole

Membrane-bound sacs in eukaryotic cells that function as storage of water and other macromolecules to the release of waste from a cell.

Mitochondria

Double-membrane structures that function in the production of ATP energy that eukaryotic cells use for cell work.

Chloroplast

Structures found in plant cells that function for capturing energy from the sun and producing sugar for organisms.

Cristae and Mitochondrial Matrix

Key internal structures of the mitochondrion, consisting of inward folds of the inner mitochondrial membrane and a gel-like fluid space containing enzymes.

Thylakoid and Stroma

A membrane-bound compartment inside plant chloroplasts and the fluid-filled space surrounding the membrane.

Secretory Pathway

A cellular assembly line that synthesizes, modifies, and transports proteins and lipids to their correct destinations inside or outside the cell.

Hydrolytic Enzymes

Natural proteins found in lysosomes that use water to break large chemical bonds in molecules into smaller, simple pieces.

Surface Area to Volume Ratio

Compares the outer surface area of an object to its internal volume.

Diffusion Distance

The average space a particle, molecule, or carrier moves from its starting point via random thermal motion over a given time.

Fluid Mosaic Model

Scientific theory that describes the structure and behavior of the plasma membrane surrounding a cell.

Phospholipid Bilayer

A double layer of lipid molecules that form the fundamental structure of every cell membrane.

Amphipathic

Having both hydrophilic and hydrophobic parts in a single molecule.

Glycoproteins and Glycolipids

Specialized biomolecules found on the outer surface of cell membranes that feature carbohydrate chains attached to either proteins or lipids.

Membrane Cholesterol

Vital lipid molecule embedded within the cell membrane of animal cells, acting as a structural stabilizer and fluidity buffer.

Selective Permeability

Allows certain molecules to pass through while blocking others, such as large molecules or charged molecules.

Transport Protein

Specialized proteins that move other substances such as ions, nutrients, and molecules across cell membranes or through the body.

Concentration Gradient

The gradual change in the concentration of a substance from one area to another across a space.

Passive Transport

Describes how molecules move naturally across a cell membrane from a place of high concentration to a place of low concentration without using energy.

Channel Protein

A special type of transport protein that spans the cell membrane forming a hydrophilic pore that allows specific water molecules or small polar molecules to pass through.

Aquaporin

A special protein channel in a cell's membrane that lets water molecules pass through quickly.

Osmosis

The movement of water across a semipermeable membrane from an area of high water concentration to low water concentration.

Hypertonic (Higher Solute Concentration)

A solution that has a higher concentration of solutes (like salt or sugar) than another solution, causing water to flow out of cell.

Hypertonic (Lower Solute Concentration / Hypotonic text note)

A solution that has lower concentration of solutes than another solution, causing water to flow into cell.

Isotonic

A solution that has an equal concentration of solutes compared to another solution, resulting in no net change in water movement.

Water Potential

The measure of the relative tendency of water to move from one area to another, driven by differences in solute concentration and pressure. Pure water has the highest water potential, set at $0$, and water always flows from areas of higher (less negative) water potential to lower (more negative) water potential.

Solute Potential

Also called osmotic potential, this is the component of water potential due to the presence of dissolved solutes. Adding solutes decreases water potential (making it more negative) because solute particles bind free water molecules and restrict their movement.

Osmoregulation

The active regulation and maintenance of the constant osmotic pressure and water-to-salt balance inside an organism's body fluids or cells relative to its environment.

Turgor Pressure

The outward physical pressure exerted by the fluid contents of a living cell (specifically the central vacuole in plants) against the inside of the cell wall. It creates a positive pressure potential that keeps plant tissues rigid and upright.

Plasmolysis

The process in plant cells where the cytoplasm shrinks and pulls away from the rigid cell wall. This happens because the cell is placed in a hypertonic environment (lower water potential outside), causing water to rush out of the cell.

Active Transport

The movement of substances across a cell membrane from a low concentration to high concentration which requires cellular energy.

ATP (Adenosine triphosphate)

The main energy currency of the cell that powers active transport and other vital cellular tasks.

Sodium-potassium Pump

A specific protein pump that uses ATP to move $3$ sodium ions out of a cell and $2$ potassium ions into it.

Endocytosis

A type of active transport that brings large molecules, fluids, or whole particles into a cell by engulfing them in a membrane vesicle.

Exocytosis

A process where a cell expels waste or releases materials by fusing an internal vesicle with the outer cell membrane.

Electrochemical Gradient

The combined force of a chemical concentration difference and an electrical charge difference across a cell membrane.

Cell Compartmentalization

The way a cell divides its internal space into smaller enclosed areas.

Membrane Bound Organelle

A specialized structure inside a cell surrounded by its own lipid membrane.

Endosymbiosis

Biological relationship where one organism lives inside the body or cells of another unrelated organism, usually benefitting both.