Overview of Biophysical Chemistry

Question 1

What percentage of the typical cell is water?

Answer 1

70%

Question 2

What is the biochemical significance of water?

Answer 2

Biomolecules interact with water to form an aqeuous solution essential for maintaining life

Question 3

What is the structure of water?

Answer 3

Oxygen chemically bonded to two hydrogen atoms
Exists in bent geometry

Question 4

What is electronegativity?

Answer 4

Power of an atom in a molecule to attract electrons

Question 5

How do transient electrical charges occur in water?

Answer 5

Due to electronegativity difference between H and O
Causes +ve charge on H and -ve charge on O

Question 6

How do hydrogen bonds form between water molecules?

Answer 6

Transient -ve charges on O atom and transient +ve charges on H atom of different H₂O molecules attract each other forming hydrogen bonds

Question 7

Density of ice and water

Answer 7

Ice = 0.92 g/ml
Water (at 0°C) = 1.0g/ml

Question 8

What is a Bronsted-Lowry Acid?

Answer 8

Proton (H⁺) donor

Question 9

What is a Bronsted-Lowry Base?

Answer 9

Proton (H⁺) acceptor

Question 10

Dissociation of an acid forms …

Answer 10

… proton and conjugate base

Question 11

Combination of proton with base forms …

Answer 11

… conjugate acid

Question 12

Strong acids have a ____ conjugate base

Answer 12

Strong acids have a __weak__ conjugate base

Question 13

What is an alkali?

Answer 13

Metal hydroxides
E.g. NaOH and KOH

Question 14

Dissociation of an alkali forms …

Answer 14

… metallic ion and OH^- ion
Hydroxide ion is a base

Question 15

What is an ampholyte?

Answer 15

Substance which can function as both an acid and base
E.g. water

Question 16

How can pH be calculated?

Answer 16

pH = -log[H⁺]

Question 17

What is a solution?

Answer 17

Homogeneous mixture of two or more substances

Solutions are formed from solutes dissolved in a solvent

Question 18

What is a solute?

Answer 18

Component of a solution that is present in lesser quantity than the solvent

Question 19

What is a solvent?

Answer 19

Component of a solution that is present in the largest quantity

Question 20

What is an aqueous solution?

Answer 20

Solution with water as the solvent

Question 21

What are the general properties of a liquid solution?

Answer 21

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

Question 22

What is a true solution?

Answer 22

Homogenous mixture with uniform properties throughout
Solute cannot be isolated from solvent by filtration, nor do the particles settle over time

Question 23

What is a colloidal suspension?

Answer 23

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

Question 24

Distinguish between solute types based on particle sizes

Answer 24

<1nm are solution particles
1nm-100nm are colloids
>100nm are precipitates

Question 25

What is the Tyndall effect?

Answer 25

Colloid particles are large enough to scatter light Used to distinguish between true and colloidal solutions

Question 26

How does polarity affect solubility?

Answer 26

Polar solute are soluble in polar solvents Non-polar solutes are soluble in non-polar solvents

Question 27

What factors can affect the degree of solubility?

Answer 27

Difference in polarity between solute and solvent (Greater diference = less soluble) Intermolecule forces Temperature

Question 28

What is a saturated solution?

Answer 28

Solution containing all the solute that can be dissolved at a particular temperature

Question 29

What is diffusion?

Answer 29

Net movement of solute or solvent molecules from an area of their high concentration to an area of low concentration

Question 30

What is osmosis?

Answer 30

Diffusion of a solvent through a semi-permeable membrane in response to a conc. gradient

Question 31

What is osmolarity?

Answer 31

Number of solute particles per 1L of solvent

Question 32

What are isotonic solutions?

Answer 32

Solutions of equal osmotic pressures E.g. RBC in plasma or 0.15M NaCl

Question 33

What are hypotonic solutions?

Answer 33

Solution with comparatively less osmolarity E.g. RBCs swell and may burst due to osmosis of water into cells

Question 34

What are hypertonic solutions?

Answer 34

Solution with comparitively more osmolarity E.g. RBCs shrink due to outward movement of water - can occur upon consumption of sea water