Bio-Tech #2 Flashcards
Why do biochemist like to get their dick wet in water?
- ) Biological molecules assume their shape/function in response to the physical/chemical properties of water.
- ) The medium for the majority of biochemical reactions is water.
- ) Water itself can actively participate in many chemical reactions that support life. (ionic components of water: H+ and OH-)
- ) The oxidation of water to produce molecular oxygen (O2) is a fundamental reaction in photosynthesis.
Bond angle of water
104.5
tetrahedral bond angle
109.5
How do water molecules “associate”?
Through hydrogen bonds
What acts as the acceptor for a water-water hydrogen bond?
The lone pair of electrons on the oxygen
How many water molecules can attach to one single H2O molecule?
4! (1 per lone pair, 1 per H)
What acts as the donor for a water-water hydrogen bond
The waters hydrogen atoms.
The weakly acidic O-H bond acts as a hydrogen “donor” (D)
Why is water stable?
because of hydrogen bonding
What are some common functional groups that also form hydrogen bonds?
electrons on:
a carbonyl C=O,
a nirtogen =N-,
Water
Hydrogens on electronegitive atoms (O, N, F)
density of water vs ice
water: 1 g/mL
ice: 0.92 g/mL
Structure of ice
Ice is a crystal lattice of H-bond donors/acceptors tetrahedrally surrounded (bond angle of 109.5°)
whats good with water in its liquid phase?
Liquid water has rapidly fluctuating structure.
3- to 7-member rings (breaking and reforming every 2 x 10-11 seconds).
Reorients every 10^-12 sec
Why is water the “universal” solvent?
water doesn’t dissolve all solutes, but it dissolves more types of substances (and in greater amounts) than any other solvent.
What dissolves in water?
water dissolves more polar and/or charged molecules, (hydrophilic).
Nonpolar substances are virtually insoluble in water, which are (hydrophobic)
As the dielectric constant increases, the force between two charges _________
decreases.
