L19 Biophysics Flashcards
💧Water is often called the ‘universal…’
a) liquid
b) solute
c) solvent
d) molecule
c) solvent
Water dissolves more substances than any other known liquid
Water is has an unusually high boiling point due to…
Hydrogen bonding between water molecules
Small ionic compounds dissolves in water. So do larger molecules with…
Polar or charged side-groups
Apolar groups are hydrophobic. They are a major factor contributing to…
Protein folding
Fatty acids are:
a) Amphipathic / amphiphilic
b) Hydrophilic
c) Hydrophobic
d) Universal solvents
a) Amphipathic / amphiphilic
They contain both hydrophilic (phosphate head) and hydrophobic (fatty acid tail) parts!
1 Mole (Avogadro’s number) =
6 x 10^23
Molarity is the number of moles (m) per…
Litre (L)
Molar is a unit of
a) concentration
b) volume
c) atomic mass
a) concentration
e. g. 1 Molar = 1 mole / 1 Litre
Small particles diffuse ( slower / faster ) than larger particles
Faster
Lower probability of collisions
Diffusion is the net flux of molecules…
Down a concentration gradient due to random thermal motion
Diffusion equation
J = P x ([C1] - [C2])
Or, Flux equals permeability multiplied by the difference in concentration
Which statement is true?
a) Diffusion rate is slow over any distance
b) Diffusion rate is slow only over short distances
c) Diffusion rate is fast over any distance
d) Diffusion rate is fast only over short distances
d) Diffusion rate is fast only over short distances
The longer the distance, the greater the probability of collision, so as distance covered increases, the rate of increase over time declines
E.Coli doesn’t need active transport. It is small enough for even a protein to diffuse across the entire diameter of the cell in…
20ms
If signals moved along neurons by diffusion alone, a 1cm neuron would take…
20 days to pass on its signal
In the body, diffusion often occurs in the presence of…
Semi-permeable membranes (barriers)
