Overview of Biophysical Chemistry Flashcards
What percentage of the typical cell is water?
70%
What is the biochemical significance of water?
Biomolecules interact with water to form an aqeuous solution essential for maintaining life
What is the structure of water?
Oxygen chemically bonded to two hydrogen atoms
Exists in bent geometry
What is electronegativity?
Power of an atom in a molecule to attract electrons
How do transient electrical charges occur in water?
Due to electronegativity difference between H and O
Causes +ve charge on H and -ve charge on O
How do hydrogen bonds form between water molecules?
Transient -ve charges on O atom and transient +ve charges on H atom of different H2O molecules attract each other forming hydrogen bonds
Density of ice and water
Ice = 0.92 g/ml
Water (at 0°C) = 1.0g/ml
What is a Bronsted-Lowry Acid?
Proton (H+) donor
What is a Bronsted-Lowry Base?
Proton (H+) acceptor
Dissociation of an acid forms …
… proton and conjugate base
Combination of proton with base forms …
… conjugate acid
Strong acids have a ____ conjugate base
Strong acids have a __weak__ conjugate base
What is an alkali?
Metal hydroxides
E.g. NaOH and KOH
Dissociation of an alkali forms …
… metallic ion and OH- ion
Hydroxide ion is a base
What is an ampholyte?
Substance which can function as both an acid and base
E.g. water
How can pH be calculated?
pH = -log[H+]
What is a solution?
Homogeneous mixture of two or more substances
Solutions are formed from solutes dissolved in a solvent
What is a solute?
Component of a solution that is present in lesser quantity than the solvent
What is a solvent?
Component of a solution that is present in the largest quantity
What is an aqueous solution?
Solution with water as the solvent
What are the general properties of a liquid solution?
Clear and transparent with no visible particles of solute
May be colored or colorless
Solution of electrolytes are good conductor of electricity whereas non-electrolyte solutions aren’t
What is a true solution?
Homogenous mixture with uniform properties throughout
Solute cannot be isolated from solvent by filtration, nor do the particles settle over time
What is a colloidal suspension?
Consists of solute particles distributed throughout the solvent
Distribution is not completely homogeneous due to the size of the colloidal particles
To the naked eye, colloidal and true solutions appear identical
Distinguish between solute types based on particle sizes
<1nm are solution particles
1nm-100nm are colloids
>100nm are precipitates
What is the Tyndall effect?
Colloid particles are large enough to scatter light
Used to distinguish between true and colloidal solutions
How does polarity affect solubility?
Polar solute are soluble in polar solvents
Non-polar solutes are soluble in non-polar solvents
What factors can affect the degree of solubility?
Difference in polarity between solute and solvent (Greater diference = less soluble)
Intermolecule forces
Temperature
What is a saturated solution?
Solution containing all the solute that can be dissolved at a particular temperature
What is diffusion?
Net movement of solute or solvent molecules from an area of their high concentration to an area of low concentration
What is osmosis?
Diffusion of a solvent through a semi-permeable membrane in response to a conc. gradient
What is osmolarity?
Number of solute particles per 1L of solvent
What are isotonic solutions?
Solutions of equal osmotic pressures
E.g. RBC in plasma or 0.15M NaCl
What are hypotonic solutions?
Solution with comparatively less osmolarity
E.g. RBCs swell and may burst due to osmosis of water into cells
What are hypertonic solutions?
Solution with comparitively more osmolarity
E.g. RBCs shrink due to outward movement of water - can occur upon consumption of sea water
