Unit C: Cycling of Matter in Living Systems - Cell Structures and Transport

Vocabulary practice flashcards covering cell types, cell membrane structures, passive and active transport, tonicity, cellular technologies, and surface area to volume dynamics.

Prokaryotes

Unicellular organisms whose cells lack a nuclear membrane or nucleus, with Greek origin meaning 'before nucleus'.

Eukaryotes

Organisms whose cells contain a true nucleus surrounded by a nuclear membrane, including all multicellular species and some unicellular organisms.

Open System

A system, such as a biological cell, that allows both energy and matter to enter and exit.

Solute

The substance dissolved in a solution, which can exist in solid, liquid, or gas states.

Solvent

The substance in a solution that dissolves the solute, with water being known as the universal solvent.

Concentration Gradient

The difference in solute concentration across a space or cell membrane that drives solute movement from higher to lower concentration.

Dynamic Equilibrium

A state reached when solute concentrations become equal across a membrane, resulting in equal rates of forward and reverse movement.

Cell Membrane

A thin, flexible phospholipid bilayer surrounding every cell that regulates internal conditions by controlling transport.

Semi-permeable

Describing a membrane that permits certain substances to pass through while blocking others.

Selectively Permeable

Describing the cell membrane's precise capability to choose specific materials that enter or exit the cell.

Phospholipid Bilayer

A double layer of phospholipids forming the fundamental structure of the cell membrane.

Hydrophilic Head

The water-attracting outer region of a phospholipid composed of a negatively charged phosphate group.

Hydrophobic Tail

The water-repelling inner region of a phospholipid made of non-polar carbon and hydrogen chains.

Passive Transport

The movement of substances across a cell membrane along a concentration gradient without requiring cellular energy.

Simple Diffusion

The passive transport of small, non-polar molecules like $O_2$ and $CO_2$ directly across the phospholipid bilayer.

Osmosis

The passive diffusion of water across a selectively permeable membrane when solutes cannot pass.

Facilitated Diffusion

The passive transport of large or charged substances across a cell membrane through specialized transport proteins.

Transport Proteins

Specialized membrane-bound proteins that assist specific molecules or ions in crossing the cell membrane.

Channel Proteins

Water-filled transmembrane proteins that open to permit charged ions to move passively down their concentration gradient.

Carrier Proteins

Transmembrane proteins that bind to specific molecules like glucose, undergoing shape changes to move them across the membrane.

Active Transport

The energy-requiring movement of solutes across a cell membrane against their concentration gradient from low to high concentration.

Integral Membrane Protein

A protein permanently attached to and spanning across the cell membrane to facilitate substance movement.

Peripheral Membrane Protein

A protein temporarily bound to the exterior surface of a cell membrane that moves molecules around the cell.

Lipid Anchored Protein

A protein covalently linked to membrane lipids, anchored on one side of the bilayer to function as a receptor for endocytosis.

Protein Pumps

Transmembrane proteins that utilize $ATP$ energy to transport ions or molecules across membranes against gradients.

Sodium-Potassium Pump

An active transport protein in animal cell membranes that uses energy from $ATP$ to export three $Na^+$ ions for every two $K^+$ ions imported.

Endocytosis

An active transport process where the cell membrane engulfs external particles into a vesicle to bring them into the cell.

Exocytosis

The reverse of endocytosis, where intracellular vesicles fuse with the cell membrane to export large substances.

Tonicity

The measure of effective osmotic pressure between two solutions across a semi-permeable membrane that determines water flow.

Hypertonic Solution

A solution with higher solute concentration than the cytoplasm, causing net water loss and cell shrinking.

Hypotonic Solution

A solution with lower solute concentration than the cytoplasm, causing net water intake until the cell swells and bursts.

Isotonic Solution

A solution with equal solute concentration to the cytoplasm, resulting in equal rates of water movement and normal cell size.

Hemodialysis

A clinical procedure that filters waste products from blood outside the body using a machine with a semipermeable dialyzer membrane.

Peritoneal Dialysis

A home-based dialysis method where dialysate solution is infused into the abdominal cavity to pull wastes across peritoneal blood vessels.

Reverse Osmosis

A water purification technique using applied pressure to force water through a semipermeable membrane against its natural osmotic direction.

Transdermal Patch

A adhesive skin patch with a semi-permeable backing that delivers medication into the bloodstream via continuous diffusion.

Liposomes

Phospholipid bilayer spheres used to deliver encapsulated medication into target cells through membrane fusion.