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Anatomy & Physiology: Chemistry of Life

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  • Matter

    Matter is anything that occupies space and has mass.

  • Mass vs Weight

    Mass is the amount of matter in a substance; Weight is the force of gravity on that mass.

  • Element

    An element cannot be split into smaller substances by ordinary means.

  • Main elements in the human body

    96% of the body is made from 4 elements: Oxygen (O), Carbon (C), Nitrogen (N), Hydrogen (H).

  • Atom structure

    An atom has a nucleus with protons (+) and neutrons (neutral), and electrons (-) orbiting in energy shells.

  • Atomic number and mass number

    Atomic number = number of protons; Mass number = protons + neutrons.

  • Isotope

    An isotope is an atom of the same element with a different number of neutrons.

  • Ion

    An ion is an atom that has gained or lost electrons, acquiring a charge.

  • Molecule vs Compound

    A molecule is 2+ atoms bonded; a compound is 2+ atoms of different elements bonded.

  • Mixture types

    Suspension: large particles settle out.
    Colloid: small particles do not settle.
    Solution: solute dissolved in solvent, clear.

  • Ionic bonds

    Formed when cations (+) and anions (-) attract; ionic compounds dissociate easily in water.

  • Covalent bonds

    Atoms share 1, 2, or 3 pairs of electrons; strongest chemical bonds in the body.

  • Nonpolar vs Polar covalent bonds

    Nonpolar: equal sharing of electrons.
    Polar: unequal sharing, e.g., water.

  • Hydrogen bonds

    Weak bonds that link molecules together, important for molecular interactions.

  • Types of chemical reactions

    Synthesis (anabolism): A + B → AB
    Decomposition (catabolism): AB → A + B
    Exchange: A + BC → AB + C

  • Energy in chemical reactions

    Exergonic: release energy.
    Endergonic: require energy.
    Activation energy: energy needed to start a reaction.

  • Enzymes

    Biological catalysts that speed reactions, specific to substrates, and are not changed by the reaction.

  • Inorganic vs Organic compounds

    Inorganic: no C-H chains, e.g., water, salts.
    Organic: contain C-H chains, usually with oxygen, covalently bonded.

  • Water properties

    Polar solvent, high heat capacity, important for metabolism, lubrication, and cushioning.

  • Acids, bases, and salts

    Acids: dissociate into H+ and anions.
    Bases: dissociate into OH- and cations.
    Salts: dissociate into cations and anions without H+ or OH-.

  • pH and buffers

    pH measures H+ concentration; buffers maintain homeostasis by converting strong acids/bases to weak ones.

  • Dehydration vs Hydrolysis reactions

    Dehydration: anabolic, bonds monomers into polymers.
    Hydrolysis: catabolic, breaks polymers into monomers.

  • Carbohydrates

    Contain C, H, O in 1:2:1 ratio; provide energy; include monosaccharides, disaccharides, and polysaccharides like glycogen.

  • Lipids

    Contain C, H, O; hydrophobic; include triglycerides, phospholipids (cell membranes), and cholesterol.

  • Proteins

    Contain C, H, O, N; made of amino acids; functions include regulation, protection, contraction, and transport.

  • Nucleic acids

    Contain C, H, O, N, P; made of nucleotides with nitrogenous base, sugar, and phosphate; include DNA and RNA.

  • ATP structure and function

    Composed of 3 phosphate groups, 5-carbon sugar, and adenosine; provides energy for cellular work.