Unit 3 Biology Review Flashcards

These flashcards cover key concepts, definitions, and general knowledge that are essential for understanding cellular structures and functions, passive and active transport mechanisms, and laboratory terminology related to osmosis and diffusion.

Cell

The basic structural, functional, and biological unit of all living organisms.

Cell Theory

A fundamental concept in biology stating that all living things are composed of cells, cells are the basic unit of life, and all cells arise from pre-existing cells.

Organelle

A specialized subunit within a cell that has a specific function, often enclosed by a membrane.

Eukaryotic Cells

Cells that contain a nucleus and other membrane-bound organelles, found in plants, animals, fungi, and protists.

Prokaryotic Cells

Cells that lack a nucleus and other membrane-bound organelles, typically smaller and simpler than eukaryotic cells.

Passive Transport

The movement of molecules across a cell membrane without the use of energy, following concentration gradients.

Active Transport

The movement of molecules across a cell membrane using energy, typically against a concentration gradient.

Osmosis

The diffusion of water across a semipermeable membrane from a region of lower solute concentration to a region of higher solute concentration.

Hypotonic Solution

A solution with a lower concentration of solutes compared to another solution, causing cells to swell.

Hypertonic Solution

A solution with a higher concentration of solutes compared to another solution, causing cells to shrink.

Isotonic Solution

A solution with equal concentrations of solutes compared to another solution, causing no net movement of water.

Endomembrane System

A system of membranes within a cell that works together to modify, package, and transport lipids and proteins.

Facilitated Diffusion

A type of passive transport that uses transport proteins to move molecules across the cell membrane.

Brownian Motion

The random movement of microscopic particles suspended in a fluid, resulting from their collision with fast-moving molecules.

Membrane Pumps

Protein complexes in a cell membrane that actively transport ions or molecules across the membrane against their concentration gradient.

Cotransport

A mechanism in which the movement of one molecule across a membrane facilitates the movement of another molecule.

Tonicity

The ability of a solution to cause a cell to gain or lose water.

Plasmodesmata

Channels between plant cell walls that allow for transportation and communication between cells.

Chloroplast

Membrane-bound organelles in plant cells where photosynthesis occurs.

Mitochondrion

Membrane-bound organelles responsible for producing energy through cellular respiration.

Cristae

Folded inner membranes of the mitochondria where the electron transport chain occurs.

Cell Wall

A rigid layer that surrounds the cell membrane in plants, fungi, and bacteria, providing structural support.

Cytoskeleton

A network of fibers within the cell that provides structure, shape, and organization.