Chapter 2 Flashcards
Why is water the solvent of life?
It is capable of dissolving more substances than any other liquid. It has a high melting point, boiling point, and heat of vaporization. a consequence of attractions between adjacent water molecules that give liquid water great internal cohesion.
It also helps cells transport and use substances like oxygen or nutrients
What does isotonic mean?
There is no net water movement, so there is no change in the size of the cell
What does hypertonic mean?
Water will leave the cell, and the cell will shrink.
What are the properties of hydrogen bonding?
Hydrogen bonding occurs between an electronegative atom (hydrogen acceptor, like oxygen or nitrogen) and a hydrogen atom that is covalently bound to another electronegative atom (hydrogen donor), which can be in the same or another molecule.
What does hypotonic mean?
water will enter the cell creating outward pressure, and the cell will swell, possibly bursting.
What is a hydrogen acceptor?
an electronegative atom of a neighboring molecule or ion that contains a lone pair that participates in the hydrogen bond.
What is a hydrogen donor?
usually a strongly electronegative atom such as N, O, or F that is covalently bonded to a hydrogen bond
What does an amphipathic molecule have?
Have both hydrophilic and hydrophobic areas.
Hydrophilic “head group” and hydrophobic alkyl group “tail”
What are the steps of Amphipathic Biomolecules and what happens to entropy throughout?
- Dispersions of lipids in H2O (each lipid molecule forces surrounding H2O molecules to become highly ordered.
- Cluster of lipid molecules (Only lipid portions at the edge of the cluster force the ordering of water. Fewer H2O molecules are ordered, and entropy increases).
- Micelles (All hydrophobic groups are sequestered from water; ordered shell of H2) molecules is minimized, and entropy is further increased).
What are hydrophobic interactions?
The forces that hold the hydrophobic regions of the amphipathic molecules.
What do water cages do?
Water cages form a sort of ‘cage’ around a nonpolar/nonsoluble/hydrophobic molecule because they disrupt the H-bonding network. When this occurs, the molecule is not happy, and entropy drops.
What happens to entropy in amphipathic biomolecules?
Initially, entropy drops. As you liberate water, entropy increases.
What is the basis for the pH scale?
The ion product of water, Kw
What is pH?
A measure of how acidic/basic water is, ranging from 0-14.
7= neutral
pH < 7 acidity
pH>7 base
What is the pH of buffered blood?
pH is 7.4
