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Glossary - Letter N


Nematoid - Worm-shaped animal, inhabitants of water or soil, which parasitizes plants and animals, including man.

Ecological niche - space occupied by an organism in the ecosystem, including its role in the community and its position in environmental gradients of temperature, humidity, pH, soil and other conditions of existence.
Trophic level - or food level, is the position occupied by an organism in the food chain. Producers occupy the first level, primary consumers the second level, secondary consumers the third level, and so on. Decomposers can act on any trophic level.

Nucleoid - Region of the prokaryote cell where the hereditary material is concentrated.

Nucleolus - Dense body formed by maturing ribosomes, present in the nucleus of eukaryotic cells.

Nucleoplasms - Plasma contained in the nucleus of the cell. Same as karyoplasma.

Nucleotide - Unit (monomer) of nucleic acid molecules; formed by a sugar, a nitrogenous base and a phosphoric acid (phosphate); in DNA nucleotide sugar is deoxyribose (deoxyribonucleotide) and in RNA is ribose (ribonucleotide).

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