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
how permeable are membranes to glucose?
partially
what establishes ion gradients in neurons?
membrane proteins
