Membranes, ions, water and proteins Flashcards
define polarity?
ends/sides of something being different (e.g. membranes have electrical polarity)
What intermolecular bonds are prevalent in water?
H-bonds
what happens molecularly when water cools down to ice?
a lattice is made
what’s more dense, liquid or solid water?
liquid
Define ion
any atom or molecule that’s gained or lost one or more electrons- has charge
why are ions important in the body (2)?
- they carry signals (APs)
- act as an energy store (for secondary active transport)
what are the 2 broad classes of biological ions?
- ions which are physiologically useful
- ions which are biochemically useful
which ions are physiologically useful? (4)
Na+, K+, Cl-, Ca2+
which ions are biochemically useful? (3)
Mg2+, Fe3+, Ca2+
what happens when ions dissolve in water?
- ion becomes surrounded with water- forming ion-dipole bonds
- several layers of hydration shells surround the ion
How does charge density affect hydration shell?
higher charge density= larger hydration shell
What are all biological membranes made of?
lipid bilayers
What gives membranes ampipathic nature?
hydrophillic , polar head and a hydrophobic non- polar tail
Are ions normally attracted or repelled by the lipid bilayer?
repelled
why are membranes partially permeable to water?
water is only partially charged
