Water and PH Flashcards
What enable water to dissolve large quantities of charged compounds such as salts.?
strong dipole and high dielectric constant
What physical properties is influnced by the hydrogen bond?
High viscosity, BP, Surface tension increase
This can serve both as hydrogen acceptors and as donors of unshielded hydrogen atoms for formation of hydrogen bonds
Alcohols, carboxylic acids, and amines
this bond is the strongest force that holds molecules together
Covalent
what is phospholipid bilayer called?
phosphatidylserine or phosphatidylethanolamine
Hydrophobic Interactions
Hydrophobic interaction refers to the tendency of nonpolar compounds to self-associate in an aqueous environment.
this minimizes the disruption of energetically favorable interactions between the surrounding water molecules in hydrophobic interaction.
Self-association
Electrostatic Interactions
Interactions between charged groups help shape biomolecular structure.
Electrostatic interactions between oppositely charged groups within or between biomolecules are termed
salt bridges
van der Waals Forces
van der Waals forces arise from attractions between transient dipoles generated by the rapid movement of electrons of all neutral atoms.
van der Waals interactions in dna is between
the stacked purine and pyrimidine bases.
Nucleophilic attack by water typically results in the cleavage of the amide, glycoside, or ester bonds that hold biopolymers together. This process is termed .
hydrolysis
The ability of water to……, while slight, is of central importance for life
water to ionize
water can act both as an acid and as a base
water Protons exist in solution not only as H3O+, but also as multimers such as H5O2+ and H7O3+
The actual probability of a hydrogen atom in pure water existing as a hydrogen ion is approximately 1.8 × 10−9.
1.8 × 10−9.
The term pH was introduced in 1909 by
Sörensen
Compounds that contain ………. can serve as hydrogen bond donors and/or acceptors.
O or N
……….. dictate that macromolecules expose polar regions to an aqueous interface and bury nonpolar regions.
Entropic forces
this forces participate in maintaining molecular structure.
Salt bridges, hydrophobic interactions, and van der Waals
The strength of weak acids is expressed by pKa, the negative log of the acid dissociation constant. Strong acids have low pKa values and weak acids have high pKa values.
Buffers resist a change in pH when protons are produced or consumed. Maximum buffering capacity occurs ±1 pH unit on either side of pKa. Physiologic buffers include bicarbonate, orthophosphate, and proteins.
