IBDP Biology A2.1 Origins of Cells

Amphipathic

A molecule that has both hydrophilic (water-attracting) and hydrophobic (water-repelling) properties.

Anabolic Reaction

A metabolic process that builds larger molecules from smaller ones, requiring energy.

Atmosphere

The layer of gases surrounding a planet, essential for life and influencing climate.

Bilayer

A double layer of molecules, such as phospholipids, that forms the structure of cell membranes.

Biomarker

A measurable indicator of a biological state or condition, often used in medical diagnostics.

Carbon Compound

A chemical compound that contains carbon atoms, forming the basis of all known life.

Catalysis

The acceleration of a chemical reaction by a substance called a catalyst, which is not consumed in the reaction.

Cell

The basic structural and functional unit of all living organisms.

Compartmentalization

The division of cellular processes into separate areas or compartments within a cell.

Deductive Reasoning

A logical process where conclusions are drawn from general principles or premises.

Emergent Property

A characteristic of a system that emerges from the interactions of its components, not present in individual parts.

Extraplanetary

Relating to or originating from outside of Earth.

Fatty Acid

A carboxylic acid with a long aliphatic chain, which can be saturated or unsaturated.

Free Oxygen

Oxygen that is not chemically bound to other elements, essential for aerobic respiration.

Hydrothermal Vent

An opening in the sea floor that emits hot, mineral-rich water, supporting unique ecosystems.

Inorganic Molecule

A molecule that does not primarily consist of carbon-hydrogen bonds, often found in minerals.

Isotope

Variants of a chemical element that have the same number of protons but different numbers of neutrons.

Life

The condition that distinguishes organisms from inorganic matter, characterized by growth, reproduction, and response to stimuli.

LUCA

Last Universal Common Ancestor, the most recent organism from which all life on Earth descended.

Micelle

An aggregate of surfactant molecules in a colloidal solution, often forming spherical structures.

Miller-Urey Experiment

A scientific experiment that simulated early Earth conditions to test the origin of organic compounds.

Molecular Clock

A method used to estimate the time of evolutionary divergence between species based on genetic mutations.

Monomer

A small molecule that can join together with other similar molecules to form a polymer.

Organic Molecule

A molecule that contains carbon and is typically found in living organisms.

Ozone

A molecule composed of three oxygen atoms, forming a layer in the Earth's stratosphere that protects against UV radiation.

Polymer

A large molecule made up of repeating structural units (monomers) connected by covalent bonds.

Polymerization

The process of chemically bonding monomers together to form a polymer.

Pre-Biotic

Referring to the conditions or processes that existed before the emergence of life on Earth.

Protocell

A simple, membrane-bound structure that is considered a precursor to living cells.

Reducing Atmosphere

An atmosphere rich in hydrogen and lacking in oxygen, believed to be present on early Earth.

Ribozyme

An RNA molecule that can catalyze chemical reactions, similar to the function of enzymes.

Ribonucleic Acid (RNA)

A nucleic acid that plays a crucial role in coding, decoding, regulation, and expression of genes.

Self-Assembly

The process by which molecules spontaneously organize into structured arrangements without external guidance.

Self-Replicate

The ability of a molecule or structure to make copies of itself.

Self-Sustaining

The ability of a system to maintain itself without external input.

Spontaneous

Occurring naturally without external cause or intervention.

Stromatolite

Layered sedimentary formations created by the activity of microbial mats, often found in ancient rocks.

Ultraviolet

A type of electromagnetic radiation with a wavelength shorter than visible light, harmful in high doses.

Vesicle

A small, membrane-bound sac within a cell that transports materials.

Virus

A microscopic infectious agent that can only replicate inside the living cells of an organism.