Chapter 1 and 2 Flashcards
(29 cards)
What are the 4 major classes of biomolecules?
Proteins, carbohydrates, nucleic acids, and lipids
What are the 4 most abundant elements?
CHON
How many molecules is water bonded to in liquid?
3.4
How many molecules is water bonded to in ice?
4
Describe the structure of a water molecule.
Tetrahedral, 104.5º, sp3 hybridized oxygen, bent, polar with dipole moment towards the oxygen
What are the four types of noncovalent interactions in order from strongest to weakest?
Hydrogen bonds, ionic bonds, hydrophobic interactions, and van der waals
bond strength of hydrogen bond
3-7 kcal/mol
what is hydrogen bond weakened in?
H2O
what is an ionic bond and give an example of one?
Also known as electrostatic bond, ion pair, salt bridges or linkages, Occurs between charged atoms
what is hydrophobic interaction and give an example of one?
Spontaneous clustering of nonpolar molecules in water, Requires non-polar species
Folding of proteins and formation of membranes
what is a van der waal interaction and give an example of one?
Transient (temporary) electrostatic interaction, butter stick
What are the solvent characteristics of hydrophilic molecules?
Polar, soluble in water (i.e. NaCl)
What are the solvent characteristrics of hydrophobic molecules?
Nonpolar, insoluble in water (i.e. Hexane)
What are the solvent characteristics of amphiphilic molecules?
- Contain both polar and nonpolar groups
- Form micelles in water (if not sterically hindered)
- Formation of biological membranes
- (i.e. ionized fatty acids)
What is osmosis?
Spontaneous process in which solvent (water) moves from areas of low solute concentration to high solute concentration (via semipermeable membranes)
what is osmotic pressure?
Pressure required to stop net flow of water across a membrane (through osmosis)
what is isotonic?
No net movement of water Concentrations are equal inside and out
what is hypotonic?
Concentration greater inside
Water enters cell, cell swells until it bursts
what is hypertonic?
Concentration greater outside
Water flows out and cell shrinks
Water _________ ionic interactions.
weakens
Strong acids and strong bases ________________ in water.
Dissociate completely
What are buffers composed of?
Weak acid and its conjugate base
What is the function of buffers?
To keep pH near constant, despite small additions of acid or base
Concentration of a buffer is _______________________
The sum of acid plus salt
