Characteristics of Living Organisms and Levels of Biological Organisation

A set of vocabulary flashcards covering the defining characteristics of living organisms, metabolic processes, and the hierarchy of biological organisation.

Movement

A change in position or location by the whole organism or part of it.

Respiration

Chemical reactions inside cells that break down nutrients to release energy.

Sensitivity

Detecting and responding to changes inside or outside the body.

Growth

A permanent increase in size and dry mass, usually through cell division and/or cell enlargement.

Reproduction

Producing new individuals of the same kind.

Excretion

Removing metabolic waste products and excess substances.

Nutrition

Taking in materials for energy, growth, and development.

Homeostasis

The process by which living things keep internal conditions relatively stable despite changes outside.

Locomotion

Movement of the whole organism from one place to another.

Breathing

The physical exchange of gases, such as inhaling oxygen and exhaling carbon dioxide, distinct from respiration.

Egestion

The removal of undigested food as faeces (distinct from excretion).

Autotrophs

Organisms that make their own food, usually through photosynthesis.

Heterotrophs

Organisms that obtain food from other organisms.

Metabolism

The total of all chemical reactions in an organism's cells that keep it alive, consisting of both catabolism and anabolism.

Catabolism

Metabolic reactions in which large, complex molecules are broken into smaller ones, releasing energy.

Anabolism

Metabolic reactions in which smaller molecules are joined to form larger, complex molecules, requiring or using energy.

Enzymes

Biological catalysts that speed up metabolic reactions and ensure the right reactions occur at the right time and place.

ATP (adenosine triphosphate)

The cell's usable energy currency, formed during catabolic reactions and spent by anabolic reactions to build molecules.

Emergent properties

Functions or characteristics that appear at a higher level of biological organisation that the smaller component parts alone do not have.

Atom

The smallest unit of an element that still has that element's properties.

Molecule

Two or more atoms joined by chemical bonds.

Organelle

A specialized structure inside a cell that performs a particular job.

Cell

The smallest structural and functional unit of life.

Tissue

A group of similar cells working together for one function.

Organ

Two or more tissues arranged together to perform a specific function.

Organ system

A group of organs working together for a major body function.

Organism

An individual living thing, either unicellular or multicellular.

Population

All individuals of the same species living in a particular area.

Community

All the different populations living and interacting in an area.

Ecosystem

A community of living organisms plus the non-living environment with which they interact.

Biosphere

All ecosystems on Earth; the parts of Earth where life exists.