Introduction to Molecular and Cellular Biology: Cells and Cellular Components

Practice vocabulary flashcards covering the characteristics of life, the chemical origins of cells, Cell Theory history, prokaryotic versus eukaryotic features, and major organelle functions.

Central Dogma of Molecular Biology

The core framework of molecular biology stating that genetic information is transferred from one DNA molecule to another via DNA replication, from DNA to RNA via transcription, and from RNA to protein via translation.

Enucleation

The biological mechanism by which maturing red blood cells (erythrocytes) eject their nucleus and organelles to maximize their hemoglobin-carrying capacity.

Differentiation

The developmental process through which unspecialized cells in a multicellular organism become specialized into distinct, functional cell types.

Primordial Soup Hypothesis

The hypothesis proposed by Alexander Oparin (1924) and J.B.S. Haldane (1929) suggesting that putative conditions on the primitive Earth favoured chemical reactions that synthesized complex organic compounds from simpler inorganic precursors.

Abiogenesis

The natural process of the chemical origin of life, through which simple organic compounds and living entities arose from non-living inorganic matter.

Miller-Urey Experiment

A 1952 chemical experiment designed by Stanley Miller and Harold Urey that simulated the atmospheric and energetic conditions of the early Earth ($\sim 3$ billion years ago) and demonstrated that organic molecules like amino acids can be synthesized abiotically.

Cellular Compartments

Internal cell structures typically bound by single- or double-layer lipid membranes that establish physical boundaries for different metabolic reactions and generate regulated micro-environments.

Robert Hooke

An English scientist and philosopher (1635-1703) who improved early microscopes and coined the biological term 'cell' from the Latin word 'cella' (meaning 'small room') upon observing cork tissue.

Cell Theory

The fundamental biological principle stating that all living organisms are composed of one or more cells, the cell is the most basic unit of life, and all cells arise exclusively from pre-existing cells.

Matthias Jakob Schleiden and Theodor Schwann

The two scientists who in 1839 formulated the first two tenets of Cell Theory: all living organisms consist of one or more cells, and the cell is the most basic unit of life.

Rudolf Virchow

The scientist who in 1855 contributed the third tenet to Cell Theory: 'Omnis cellula e cellula' (all cells arise only from pre-existing cells).

Prokaryotic Cells

Single-celled organisms ranging in size from $1\,\mu\text{m}$ to $10\,\mu\text{m}$ that lack a defined nucleus and membrane-bound organelles, contain small ribosomes, possess circular DNA, and reproduce asexually.

Nucleoid

The non-membrane-enclosed, nucleus-like region in a prokaryotic cell where circular genetic material (DNA) is organized.

Pili

Hairlike surface structures that interlink bacterial cells to one another.

Eukaryotic Cells

Unicellular or multicellular organisms ranging in size from $10\,\mu\text{m}$ to $100\,\mu\text{m}$ that possess a true membrane-bound nucleus, large ribosomes, and compartmentalized organelles.

Nucleus

A membrane-bound organelle that serves as the storehouse for the cell's genetic information and the primary site for RNA synthesis.

Mitochondria

Cellular organelles responsible for producing the vast majority of the ATP that functions as the energy currency of the cell.

Endoplasmic Reticulum

An interconnected network of internal cellular membranes involved in both protein and lipid synthesis.

Golgi Apparatus

A cellular organelle that modifies and sorts proteins and lipids as they move toward their final destinations inside or outside the cell.

Lysosomes

Specialized membrane-bound organelles responsible for degrading biological macromolecules.

Peroxisomes

Organelles that break down specific organic molecules such as fatty acids and synthesize organic lipids including cholesterol and phospholipids.

Cytoskeleton

An internal network composed of protein filaments and associated proteins that provides structural framework, organization, and mechanical support to the cell.

Plasma Membrane

A selective barrier composed of phospholipids and embedded proteins that regulates the entry and exit of substances into and out of the cell.