part I

Question 1

cell is the basic unit of

Answer 1

• life
• medicine
• evolution via mutation

Question 2

first law of thermodynamics

Answer 2

• law of conservation of energy
• in isolated systems, the amount of energy within the system is constant
• energy can be converted down tropic level, but cannot be consumed
• stored energy used for growth
• temporarily stored energy used for activity

Question 3

second law of thermodynamics

Answer 3

• entropy
• in isolated systems, prefers disorder

Question 4

energy quality

Answer 4

• high: “consumed” energy (e.g. sunlight, chemical energy)
• low: output (e.g. movement, heat)
• depends on how “free” the energy is (determined by Gibbs free energy)

Question 5

ATP

Answer 5

• binding: induces strain –> distort 3D structure
• hydrolysis: loss of strain –> increased potential energy –> drives non-spontaneous reaction
• G = 7.3 kcal/mol = 20 kBT

Question 6

reduction-oxidation reactions

Answer 6

• reduction: gain of electron
• oxidation: loss of electron
• reducing agent: being oxidized
• oxidizing agent: being reduced

Question 7

NAD+/NADH

Answer 7

• G = 52.6 kcal/mol
• NAD+ brought to position for reduction by GAPDH

Question 8

FAD/FADH2

Answer 8

G = 43.4 kcal/mol

Question 9

average energy of a molecule

Answer 9

• 3/2 kBT
• due to Brownian motion: random collisional motions driven by thermal energy

Question 10

energy unit conversions

Answer 10

1 kBT = 0.6 kcal/mol = 4.1 pNnm = 25 meV = 4.110^-31 J

Question 11

visible photon

Answer 11

2 eV

Question 12

electrostatic interaction

Answer 12

to move 2 opposite charged molecules closer by 0.15nm –> 2.3 kBT

Question 13

probability of a molecule to be at a certain energy

Answer 13

P = e^(-E/kBT)

Question 14

hydrogen bond strength

Answer 14

2-12 kBT

Question 15

cytoplasm characteristics

Answer 15

• crowded
• rough and rumble due to Brownian motion: diffusion coefficient (D) dependent on molecule size –> larger molecule, smaller D, slower diffusion
• viscous: Reynold’s number (Re) = (densityvelocitylength)/dynamic viscosity
• elastic
• meshwork: pore size determined by organelles, polymers and other structures
• active: carbon starvation/ATP depletion –> glass-like cytoplasm, not thermal –> increased fluidity due to dissipation of “unused” energy from ATP hydrolysis that locally increases thermal energy