Glossary

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Term Term description
NADPH

A reduced form of nicotinamide adenine dinucleotide phosphate (NADP - a coenzyme occurring in most living cells), used in a number of reductive synthesis such as fatty acids and steroids.

native elements

Some 20 elements occur in nature in a pure (i.e., uncombined) or nearly pure form. They are partitioned into three families: metals, semimetals, and nonmetals. Examples include gold, carbon, aluminum, lead, tin, and zinc.

natural resources

Something, such as a forest, a mineral deposit, or fresh water, that is found in nature and is necessary or useful to humans.

natural selection

 

The mechanism for evolutionary change in which environmental pressures cause certain genetic combinations in a population to become more abundant; genetic combinations best adapted for present environmental conditions tend to be selected for, and non-adaptive traits are selected against.

 

natural world

The world and its naturally occurring phenomena, together with all of the physical laws that govern them. 

naturalist

A person who studies and appreciates nature.

nature

The phenomena of the physical world collectively, including plants, animals, the landscape, and other features and products of the earth.

nature

The phenomena of the physical world collectively, including plants, animals, the landscape, and other features and products of the earth.

nebula

A large cloud of particles and gases in space that is visible either as a hazy patch of light (either an emission or a reflection nebula) or an irregular dark region against a brighter background (dark nebula).

nefesh

Hebrew term meaning 'living being'; commonly rendered as 'soul' in English translations.

niche

 

The functional position or role of an organism in its ecosystem.

 

nitrate

A compound containing the group NO3. Nitrates dissolve extremely easily in water and are an important component of the nitrogen cycle. They are easily used by plants and algae.

nitrification

The oxidation of an ammonia (NH3) compound into nitric acid (HNO3), nitrous acid (HNO2), or any nitrate (NO3-) or nitrite (NO2-), usually through the action of bacteria.

nitrifying bacteria

Bacteria that change ammonium (NH3) compounds into nitrites (NO2) or change nitrites into nitrates (NO3) as part of the nitrogen cycle.

nitrite

A compound containing the group NO2. Nitrites are an important component of the nitrogen cycle and are used as food preservatives.

nitrogen

An element that forms 78% of our atmosphere in the form of N2 gas and is one of the most abundant elements within the universe. Nitrogen gas must be converted into ammonium ions through nitrogen fixation, a process carried out by certain specialized bacteria, in order for nitrogen to be converted to a chemical form that can be utilized by plants and ultimately animals and humans.

nitrogen cycle

Cyclic movement of nitrogen in different chemical forms from the environment to organisms and then back to the environment.

nitrogen fixation

The process by which nitrogen in the atmosphere is converted into ammonium.

nitrogen fixers

Microorganisms involved in the process of converting relatively inert atmospheric nitrogen (N2) into biologically available forms, ammonia (NH3) or nitrous oxide (NO2).

nitrogenase

An enzyme complex that catalyzes the reduction of molecular nitrogen in the nitrogen-fixation process of bacteria.

nitrous oxide

A potent greenhouse gas. In 2012, nitrous oxide (N2O) accounted for about 6% of all U.S. greenhouse gas emissions from human activities. Activities such as agriculture, fossil fuel combustion, wastewater management, and industrial processes are increasing the amount of N2O in the atmosphere.

non-biodegradable

A substance that cannot be decomposed to a harmless natural state by the action of bacteria, and may therefore damage the environment.

nonrenewable energy

Energy that comes from sources that will run out or will not be replenished in our lifetimes—or even in many, many lifetimes. Most non-renewable energy sources are fossil fuels: coal, petroleum, and natural gas.

Northwestern Glacier

A glacier found at the head of Northwestern Fjord in Kenai Fjords National Park in Alaska which has been steadily receding over the past century.

notrogen fixers

Microorganisms involved in the process of converting relatively inert atmospheric nitrogen (N2) into biologically available forms, ammonia (NH3) or nitrous oxide (NO2).

nuclear energy

The energy released during a nuclear reaction, a process in which the structure and energy content of an atomic nucleus are changed by interaction with another nucleus or particle.

nuclear fission

The splitting of an atomic nucleus into approximately equal parts, either spontaneously or as a result of the impact of a particle usually with an associated release of energy. Sometimes shortened to: fission

nuclear fusion

A reaction in which two nuclei combine to form a nucleus with the release of energy. Sometimes shortened to: fusion.

nuclear power

Power, especially electricity, the source of which is nuclear fission and produced by a nuclear reactor.

nucleic acids

Large organic molecules made of nucleotides that contribute to DNA and that function in the transmission of hereditary traits, in protein synthesis, and in control of cellular activities.

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