Principles of Biochemistry Chapter 2 Water

water is a ________ molecule

polar; contains a positive and negative end

in water, oxygen has a slightly ________ charge

negative

in water, hydrogen has a slightly ________ charge

positive

one water molecule can bind with ______ other water molecules at the same time

4

cohesion

Attraction between molecules of the same substance

cohesion is made possible due to

hydrogen bonds

adhesion

An attraction between molecules of different substances

adhesion is made possible due to

hydrogen bonds that bind to electronegative Os

surface tension

linking together of water molecules on the surface of a body of water

surface tension is made possible due to

hydrogen bonds

heat

total amount of kinetic energy

temperature

intensity of all the heat in a substance as the molecules move

water's ability to regulate temperature is due to

hydrogen bonds

evaporative cooling

The property of a liquid whereby the surface becomes cooler during evaporation, owing to a loss of highly kinetic molecules to the gaseous state.

water __________ when it freezes

expands

four properties of water

1. cohesion/adhesion

2. evaporative cooling

3. temperature regulation

4. water expands when it freezes

solvent

A liquid substance capable of dissolving other substances

universal solvent

water

solute

A substance that is dissolved in a solution.

solution

A mixture in which one or more substances are evenly distributed in another substance

hydration shell

The sphere of water molecules around each dissolved ion

water can not grab and dissolve ________ molecules

non-polar (oils, grease, fats)

hydrophobic

"water fearing"

hydrophilic

"Water loving"

dissociation

splitting of water into H+ (proton) and an OH- (hydroxide ion)

acid

substance gives away H+

base

substance gives away OH-

pH scale

measurement system used to indicate the concentration of hydrogen ions (H+) in solution; ranges from 0 to 14 pH =(-)logH+. A log scale.

buffer

A solution that resists changes in pH when limited amounts of acid or base are added.

biocarbonate

buffer found in human blood; keeps blood at a pH of 7.4

acid precipitation

Rain, snow, or fog that is more acidic than pH 5.6.

causes of acid precipitation

burning of fossil fuels; sulfur oxide and nitrous oxide combine with water

what bond makes water possible

polar covalent

what bond provides the properties of water

hydrogen

adhesion of water

the water is attracted to the glass

cohesion of water

water molecules are attracted to each other and form droplets

example of hydration shell

the water molecules surround the molecules

surface tension of water

Water molecules want to cling to each other. At the surface, however, there are fewer water molecules to cling to since there is air above (thus, no water molecules). This results in a stronger bond between those molecules that actually do come in contact with one another, and a layer of strongly bonded water. This surface layer creates a considerable barrier between the atmosphere and the water.

hydrogen acceptor

atom, ion, or molecule component of a hydrogen bond which does not supply the bridging (shared) hydrogen atom Ie O or N

hydrogen donor

the Hydrogen atoms that are ATTACHED to the electronegative atom (O N or F)

Hydrogen bonds

The two strands of a DNA double helix are held together by _____ that form between pairs of nitrogenous bases.

dielectric constant

Solvent polarity is a measure of solvent ability to separate opposite charges, which is expressed as _________. (E)

cathrate

shell created around nonpolar substance by polar substances, decreases entropy

ampipathic

Both hydrophobic and hydrophilic

micelles

-consist of bile salts, fatty acids, monoglycerides and phospholipids all clustered together with the polar ends of each molecule oriented towards the micelle's surface and the nonpolar portions forming the core.

van der waals interactions

weak attractions between molecules or parts of molecules that result from transient local partial charges

proton hopping

Hydrogen bonded networks form natural chains for rapid proton transfer. Covalent and hydrogen bonds are interchangeable. Much faster than true diffusion, and results in extremely fast acid-base rxns.

colligative

a property that is determined by the number of particles present in a system but that is independent of the properties of the particles themselves

osmotic pressure

pressure that must be applied to prevent osmotic movement across a selectively permeable membrane when solutes are in water solution.

equilibrium constant

a ratio of products formed at equilibrium to reactants formed at equilibrium. Products/Reactants

titration curve

a graph of pH of a solution as titrant is added, expressed by a weak acid proton donor dissociates to become its conjugate base a proton acceptor. CH3COOH --> CH3COO- + H+. At equilibrium pKa = pH because changes in H+ concentration are buffered and line is stable.

Henderson Hasselbach

pH= pKa + log (base(A-)/acid(HA))

condensation reaction

A reaction in which two molecules become covalently bonded to each other through the loss of a small molecule, usually water; also called dehydration reaction.

Hydrolysis reaction

this is when water (H2O) is added to a substance in order to break it up into smaller molecules. You can identify this as having a H2O reactant.

specific heat of water

High compared to other substances. Allows Earth's large bodies of water to store heat and not be changed by small temp increases. Acts as a buffer. 1 Joule(Calorie) of heat energy needed to raise 1 Gram, 1 Degree higher.

Kw = [H+][OH-] = 1x10^-14

Ion product of H2O

pH of a solution

pH = -log_10[H+]

Logarithmic functions are closely related to exponential equations

log_b (x) = y says the same thing as b^y = x.