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A glossary of science-related words.

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A rare-earth metal (also called a lanthanide) – symbol Gd, atomic number 64.


A large-scale collection of stars, gas and dust. Galaxies are held together by gravitational attraction. The Solar System is situated in the Milky Way galaxy.

gall bladder

A small pouch-like structure that sits just beneath the liver. It stores bile produced by the liver and releases it into the duodenum during the digestion of food.


A metal – symbol Ga, atomic number 31.


Male (sperm) or female (egg) reproductive cells that contain a single set of chromosomes and are specialised for fertilisation. Gametes are haploid.


The gamete-bearing individual or phase in the life cycle of a plant that has alternation of generations. The haploid generation of the life cycle.

gamma ray

High-energy electromagnetic radiation.


Entire range or scale.


A widely open mouth or beak.


The state of matter distinguished from the solid and liquid states. Gases have the ability to diffuse readily and to become distributed uniformly throughout any container.

gastric juice

A fluid produced by the stomach lining that contains a mixture of hydrochloric acid and digestive enzymes


A hormone produced in the stomach, duodenum and pancreas that stimulates the release of hydrochloric acid in the stomach.


An inflammation of the stomach and intestine that can cause cramping, diarrhoea, vomiting and fever.


To do with the stomach and intestines.

gastrointestinal tract

The tube that extends from the mouth to the anus, which is concerned with the digestion of food. Symptoms of gastrointestinal disorders include vomiting, constipation or diarrhoea, loss of appetite and weight loss.


Any of a large class (Gastropoda) of molluscs such as snails and slugs. They typically have a large foot, a single coiled shell that covers the soft body, and a head with a pair of eyes and tentacles.

gene expression

The use of a gene to make a protein. Involves transcription of the DNA sequence into RNA and translation of the RNA into an amino acid sequence (or protein).

gene pool

The variety of genes in a population.


The plural of genus. A taxonomic category (the way all living things are categorised or sorted) ranking below a ‘family’ and above a ‘species’ and generally consisting of a group of species with similar characteristics. For example, the taxonomic name for the South Island giant moa species is Dinornis robustus. The first part of the species name Dinornis is also the genus name.


A segment of a DNA molecule within the nucleus of all cells that codes for a particular protein and determines the traits (phenotype) of the individual.


Of, relating to, or determined by genes.

genetic blueprint

A term that refers to your genome or genotype as a map or plan for your development.

genetic code

The DNA sequence of a particular organism.

genetic diversity

The variety of genetic material within a single species of organism that permits the organism to adapt to changes in the environment.

genetic fingerprinting

Using a DNA fingerprint to identify individuals or species.


The study of heredity and variation in living organisms.


The genetic material of an organism (from gene + chromosome).

genomic technology

Methods, technologies and instruments developed for genomics research. Genomic technology has increased the ability of scientists to process and analyse vast amounts of data.


A discipline in genetics that applies DNA sequencing methods and bioinformatics to sequence, assemble and analyse the function and structure of genomes.


The genetic make-up of an individual organism.


(Plural genera) A division used in the Linnean system of classification or taxonomy.


Study of the chemical composition of the Earth’s crust and the reactions of chemical elements in its minerals, rocks, soil, waters and atmosphere.


A concept that is related to or is based on geology.


Someone who studies the materials and processes that form the Earth. They try to understand how the planet has changed over time.


Study of the origin, history and structure of the Earth; the geological features of an area.


The branch of mathematics concerned with the properties, relationships and measurement of points, lines, curves and surfaces.


A scientist who studies the physical properties and processes of the Earth’s surface, interior, oceans and atmosphere.


The solid part of Earth – land and rock.

geostationary orbit

A type of orbit high above the equator where a satellite appears to remain above the same point on the Earth’s surface because the orbital period of the satellite is the same as the rate of rotation of the Earth.


Geothermal energy is energy produced from the heat of the Earth.


An agent that kills pathogenic microorganisms (germs).


The first stage of plant growth from a seed to a seedling. When conditions are right, a seed takes in water and starts to grow a root, stem and leaves.


A hormone produced in the stomach that boosts appetite, slows metabolism and reduces fat burning. It may be involved in the development of obesity.


An intestinal infection caused by a microscopic flagellated protozoan parasite.


A respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water and excretes carbon dioxide.


A cold period (sometimes called an ice age) with low sea levels because water is removed to form ice. There is a large-scale advance of glacier ice into areas that are normally ice-free.

glass eels

Transparent juvenile eels. Eel larvae – leptocephali – change into glass eels.


A coating of metal oxides and silica applied to the surface of pottery items. When fired, the glaze fuses into a glassy-like solid. Glazes are used to colour, decorate and waterproof pottery.

globular protein

A globe-shaped protein that is mostly soluble in water. The other class of proteins – fibrous proteins – are generally insoluble in water.


A simple sugar belonging to the group of carbohydrates called monosaccharides. It is the main form of carbohydrate used by the body.


An elementary particle that carries the strong, or nuclear, force. Quarks that make up protons and neutrons are effectively ‘glued’ together by gluons.


An energy-releasing process occurring in the cell cytoplasm that changes glucose into pyruvate.

glycosidic bond

The chemical bond that links simple sugars together to form disaccharides and polysaccharides.


Enlargement of the thyroid gland on the front and sides of the neck, usually caused by lack of iodine in the diet.


A transition metal in Group 11 of the periodic table – symbol Au, atomic number 79.


A continent (large landmass) in the Southern Hemisphere that eventually separated to form South America, Africa, Antarctica, Australia and New Zealand. Gondwana separated from the supercontinent of Pangaea at the end of the Paleozoic Era and broke up into the current continents in the middle of the Mesozoic Era.


A very large number defined as 10100. In long written form, it is a 1 followed by 100 zeros.


A form of arthritis caused by uric acid crystallising in joints.


Global positioning system consisting of satellites, computers and receivers that is able to determine the latitude and longitude (given position on Earth) of a receiver on Earth by calculating the time difference for signals from different satellites to reach the receiver.


A common type of crystalline igneous rock that is rich in the minerals quartz, mica and feldspars.

gravitational microlensing

Einstein predicted that a star warps the space surrounding it, enabling the star to act like a giant magnifying glass. Astronomers use this bending of light rays by the gravitational field of a massive object (the lens) to magnify the light of background objects such as distant stars that are within the line of sight of the lens. This means that astronomers can now study massive objects no matter how faint as long as they are able to use another brighter closer object to magnify the dim object. They now use this technique to study faint or dark objects such as brown dwarfs, red dwarfs, planets, white dwarfs, neutron stars and black holes.

gravitational potential energy

The energy gained by an object as its height above ground level increases.


The natural force of attraction between objects.

green body

A shaped or formed object made from a ceramic compound before it has been fired or sintered.

greenhouse gases

The main greenhouse gases are water vapour, carbon dioxide, methane, nitrous oxide, ozone and industrial gases such as chlorofluorocarbons (CFCs). These gases in the Earth’s atmosphere trap warmth from the Sun and make life possible. An overabundance of greenhouse gases leads to a rise in global temperatures – known as the greenhouse effect.


A sedimentary rock that forms much of the backbone of New Zealand. Made mainly of the minerals quartz and feldspar, with fragments of other rocks, greywacke is mostly like dark sandstone, but also contains mudstone.


The process of gathering data to test the accuracy, or otherwise, of a scientific model.


Water located beneath the Earth’s surface in soil spaces and in fractures of rocks.


A vascular plant that bears seeds not enclosed in any specialised chambers (for example, pine, ginko).


Relating to plants, having both female and hermaphrodite (having both stamens and carpels in the same flower) flowers on the same plant.


The Earth’s rotation causes the Coriolis effect which deflects wind and water on both hemispheres towards the equator. Gyres are vortexes or rotating flows that are a result of this deflection.