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  2. Composition of the human body - Wikipedia

    en.wikipedia.org/wiki/Composition_of_the_human_body

    About 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium. All 11 are necessary for life. The remaining elements are trace elements, of which more than a dozen are ...

  3. Molecule - Wikipedia

    en.wikipedia.org/wiki/Molecule

    However, the majority of familiar solid substances on Earth are made partly or completely of crystals or ionic compounds, which are not made of molecules. These include all of the minerals that make up the substance of the Earth, sand, clay, pebbles, rocks, boulders, bedrock, the molten interior, and the core of the Earth.

  4. Cell (biology) - Wikipedia

    en.wikipedia.org/wiki/Cell_(biology)

    The cell is the basic structural and functional unit of all forms of life. Every cell consists of cytoplasm enclosed within a membrane; many cells contain organelles, each with a specific function. The term comes from the Latin word cellula meaning 'small room'. Most cells are only visible under a microscope.

  5. Cellular component - Wikipedia

    en.wikipedia.org/wiki/Cellular_component

    Cellular components are the complex biomolecules and structures of which cells, and thus living organisms, are composed. Cells are the structural and functional units of life. [1] The smallest organisms are single cells, while the largest organisms are assemblages of trillions of cells. DNA, double stranded macromolecule that carries the ...

  6. Protoplasm - Wikipedia

    en.wikipedia.org/wiki/Protoplasm

    Protoplasm (/ ˈ p r oʊ t ə ˌ p l æ z əm /; [1] [2] pl. protoplasms) [3] is the part of a cell that is surrounded by a plasma membrane.It is a mixture of small molecules such as ions, monosaccharides, amino acids, and macromolecules such as proteins, polysaccharides, lipids, etc.

  7. Cytoplasm - Wikipedia

    en.wikipedia.org/wiki/Cytoplasm

    In cell biology, the cytoplasm describes all material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. The main components of the cytoplasm are the cytosol (a gel-like substance), the organelles (the cell's ...

  8. CHNOPS - Wikipedia

    en.wikipedia.org/wiki/CHNOPS

    CHNOPS. Graphic representation of carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur. CHNOPS and CHON are mnemonic acronyms for the most common elements in living organisms. "CHON" stands for c arbon, h ydrogen, o xygen, and n itrogen, which together make up more than 95 percent of the mass of biological systems. [1] ".

  9. Tissue (biology) - Wikipedia

    en.wikipedia.org/wiki/Tissue_(biology)

    The cells of meristematic tissue are similar in structure and have a thin and elastic primary cell wall made of cellulose. They are compactly arranged without inter-cellular spaces between them. Each cell contains a dense cytoplasm and a prominent cell nucleus. The dense protoplasm of meristematic cells contains very few vacuoles.