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Biochemistry. Chemical reactions in living things. Water. Water is the most important inorganic compound in living things because….. Most cellular activities take place in water solutions . Water. Polar molecule - has polar covalent bonds.
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Biochemistry Chemical reactions in living things.
Water Water is the most important inorganic compound in living things because….. • Most cellular activities take place in water solutions
Water • Polar molecule • - has polar covalent bonds. • O has a slight (-) charge • H has a slight (+) charge • (-) • O • H H • (+) (+) • Polar water molecules interact with each other by forming hydrogen bonds.
Properties of Water Cohesion: • the tendency of molecules to stick together.
Properties of water (con’t) Adhesion: • the attractive force between different substances. • Example: • trees transport water from roots to leaves.
Properties of water (con’t) Surface tension: • a measure of how difficult it is to break the surface of a liquid. • insects “walk” on the surface of water.
Properties of water (con’t) High heat capacity: • has ability to resist temperature change. • the ocean stores heat from the sun and gives it off during cooling, keeping the climate more mild.
Properties of water (con’t) Good solvent: • dissolves many solutes in all cells, blood, and plant sap.
pH • the concentration of hydrogen ions in solution • Water molecules dissociate into ions • (H+) and (OH-)
pH (con’t) • Acid- chemical compound that donates H+ atoms to solution • Base- compound that accepts H+ atoms and removes them from solution
pH (con’t) • pH scale • 0-14 range • 7 neutral • 0-7 acidic • 7-14 basic
pH (con’t) • In organisms, the pH must be maintained: • blood 7.4, stomach acid 2.0 • pH can affect the rate and nature of internal chemical reactions.