11Cohesion, Adhesion, and Surface Tension Cohesion: molecules attracted to each other – causes surface tensionAdhesion: moleculesattracted to others – endup with capillary action.Cohesion and adhesion responsible for Giant Redwoods
13Aqueous SolutionsSolution: mixture where one or more substances are evenly distributed in another substance.Ex. Salt dissolves in waterPolarity: polar easilydissolves in water;nonpolar does not dissolve well in water (oiland water)
14Acids and BasesWhen a hydrogen is stripped away from a covalent bond it leaves as an ion H+ (called a hydrogen ion), if it is stripped from a water molecule it leaves OH- a hydroxide ionCovalent bonds of water often break spontaneously-ionizationH2O → H OH-
15pH ScaleChanges in acidity (or basicity) due to an increase or decrease in hydrogen ions are measured with the pH scalepH scale is used to determine the acidic or basic nature of a solution compared to pure waterPure water has an equal concentration of hydrogen and hydroxide ions pH = 7
17Chemistry of CellsOrganic compounds are found in living things – contain carbon and are covalently bonded.Four types: carbohydrates, lipids, protein, and nucleic acids.
18Organics…Carbohydrates: C, H, O 1:2:1 (ex. Glucose – source of energy)Lipids: aka fats – nonpolar (remember the oil and water)… stores energyProteins: chains of amino acidsNucleic acids: store and transmit heredity information – DNA, RNAATP is the main source of energy in a cell.
19EnzymesStarting a chemical reaction requires activation energy (energy to start “activate”).Enzymes speed up reactions by lowering activation energy.
20More enzymes…Enzymes bind only certain substrates (in other words…they are picky!)pH and temperature affect enzyme activity…HOW?