Lesson 1 Flashcards
proteins
repeating polymers of amino acids (proteins)
nucleic acids
repeating polymers of nucleotides (DNA, RNA)
lipids and facts
generally, repeating (-CH2) - units (Fatty acids, TAGs)
Polysaccharides
repeating monosaccharide units (glycogen, cellulose, lactose, sucrose)
why is the bond angle in water 104.5 instead of 109.5 degrees
lone pairs (nonbonding electron pairs) –> take up more space compared to bonding electrons
comparing H2O to H2S - why does water have such a comparatively HIGH boiling point compared to H2S
the oxygen in H2O is more electronegative than Sulfur and is therefore better at H-bonding
H-bond doners
H+ on oxygen, nitrogen, sulfur
H-bond acceptors
lone pairs on O,N, and S(rarely)
direction and distance relationship with H-bond strength
linear is stronger than askew
closer is stronger than farther
collections of weak bonds are very () and highly ()
stable, flexible
how often does water reorient itself
every 10^-7 seconds
true/false: non polar solutes do not spontaneously dissolve in aqueous solution
true
- water molecules must become more ordered to minimize interactions with non-polar solute
dispersion of lipids in H2O
each lipid molecule forces surrounding H2O molecules to become highly ordered
clusters of lipid molecules
only lipid portions at the edge of the cluster force the ordering of water
- fewer H2O molecules are ordered, and entropy is increased
micelles
all hydrophobic groups are sequestered from water; ordered shell H2O micelles is minimized, and entropy is further increased
If you focus on the IMFs between the fatty acid chains of adjacent molecules as the micelle forms, is delta H for micelle formation positive or negative? Is heat transferred from the system (fatty acids( to the surrounding (aqueous buffer) or vice versa?
energy in the form of heat is released upon bond formation
delta H is negative
(remember that the entropy of micelle is difference from the entropy of the water molecules)
true/false: polar head groups interact with water on both surfaces of the bilayer
true
in general, the more polar, the more…
soluble in aqueous solution
in general, the more highly charged (either + or - ) =
more soluble in aqueous solution
true/false: water influences the structure of large and small biomolecules
true
