Unit 2 : Cell Structure and Function

Cell theory

A fundamental concept in biology that states: the cell is the basic unit of life, all organisms are made of cells, and all cells come from a common ancestor.

Prokaryotic cells

The simplest and most primitive cells that lack a nuclear membrane, membrane-bound organelles, and are typically bacteria.

Eukaryotic cells

More complex cells that have a true nucleus and membrane-bound organelles; evolved from prokaryotic cells.

Endosymbiotic theory

A theory that explains the origin of eukaryotic cells, proposing they evolved from prokaryotic cells that fused together.

Ribosomes

Tiny organelles responsible for linking amino acids to form proteins, made of ribosomal RNA and proteins.

Golgi apparatus

An organelle that modifies, sorts, and packages materials from the endoplasmic reticulum for transport.

Vacuole

Membranous sacs in cells that function in storage and transport of materials; particularly prominent in plant cells.

Lysosomes

Digestive compartments in animal cells that contain enzymes to break down waste materials and cellular debris.

Cilia and flagella

Organelles made of microtubules that aid in movement for some cells.

Surface area to volume ratio (SA:V)

A critical factor limiting cell size, where increasing volume requires a proportionally larger surface area for necessary metabolic processes.