Chapter 2 - Water

Question 1

hydrophilic

Answer 1

“water-loving”, compounds that dissolve easily in water; generally charged or polar compounds

Question 2

hydrophobic

Answer 2

“water-fearing”; compounds that do not dissolve easily in water; nonpolar molecules such as lipids or waxes

Question 3

amphipathic

Answer 3

compounds that contain regions that are polar (or charged) and regions that are nonpolar

Question 4

hydrogen bond

Answer 4

strong dipole-dipole or charge-dipole interaction between a proton donor and proton acceptor; found when hydrogen directly bonded to O or N; strongest when bonded molecules inline with each other

Question 5

ionic interaction

Answer 5

electrostatic interactions between charged molecules; largely affected by distance between molecules

Question 6

hydrophobic interaction

Answer 6

forces that hold the nonpolar regions of molecules together; due to thermodynamic stability, not interactions between nonpolar molecules

Question 7

Van der Waal’s interactions

Answer 7

pH = pKa + log([A⁻]/[HA])

Question 8

clathrate

Answer 8

crystalline compound of nonpolar solutes and water

Question 9

miscelle

Answer 9

stable structures of amphipathic compounds in water where nonpolar regions of molecules cluster together while hydrophilic regions of molecules maximize interactions with water

Question 10

van der Waals radius

Answer 10

a measure of how close an atom will allow another to approach

Question 11

colligative properties

Answer 11

physical properties of the solvent (water) that are altered by the solute: vapor pressure, boiling point, melting point, and osmotic pressure

Question 12

osmolarity

Answer 12

ic, where i = van’t Hoff factor (measure of the extent to which a solute dissociates into two or more ionic species) and c = the solutes molar concentration

Question 13

osmosis

Answer 13

water movement across a semi-permeable membrane driven by differences in osmotic pressure

Question 14

isotonic

Answer 14

solutions that are of osmolarity equal to that of a cell’s cytosol, where a cell neither gains nor loses water

Question 15

hypertonic

Answer 15

solution that is of a higher osmolarity than that of the cytosol, where a cell shrinks as water moves out; LESS water than solute

Question 16

hypotonic

Answer 16

solution with a lower osmolarity than the cytosol, where a cell wells are water enters; MORE water than solute

Question 17

acidosis

Answer 17

condition where pH of the blood plasma is below the normal value of 7.4

Question 18

alkalosis

Answer 18

condition where the pH of the blood is higher than 7.4

Question 19

buffer

Answer 19

relatively flat region of titration curve of a weak acid; typically +/- 1 pH unit from where pKa = pH.

Question 20

pH optimum

Answer 20

characteristic pH where enzymes show maximal catalytic activity

Question 21

hydrolases

Answer 21

enzymes that catalyze hydrolysis reactions