Module 1

Question 1

pH vs. pK_a

Protonation vs. Deprotonation

Answer 1

• pH = pK_a: Species remains Stable
• pH > pK_a: Species becomes Deprotonated
• pH < pK_a: Species becomes Protonated

Question 1

Henderson-Hasselbach Equation

Answer 1

The Henderson-Hasselbalch equation enables one to describe how changes in acid-base equilibrium affect the pH of a system.

Question 2

Energy Charge

Answer 2

Energy charge is the relationship between [ATP], [ADP],, and [AMP] at any given time in the cell.

Question 3

Specific Activity

Protein Purification

Answer 3

Total Activity / Total Protein

Unit = units/mg

Question 4

Total Fold Pure

Protein Purification

Answer 4

(Specific Activity)_Current / (Specific Activity)_Initial

Unit = None

Question 5

Total Yield

Protein Purification

Answer 5

(Total Activity)_Current / (Total Activity)_Initial

Unit = %

Question 6

Biochemistry

Answer 6

The study of living things at the molecular level.

Question 7

4 Major Elements of Living Matter

Answer 7

• Carbon: 62%
• Hydrogen: 11%
• Oxygen: 9%
• Nitrogen: 6%

Question 8

Why do biological “energy molecules” often possess Phosphorus and/or Sulfur?

Answer 8

Phosphorus-containining and Sulfur-containing covalent bonds are unstable in the presence of H₂O, so there is typically a net energy increase in when these “energy molecules” are hydrolyzed in biolgical systems.

Biological systems are comprised primarily

Question 9

Physiological Roles of Monoatomic Ions

(Na⁺, K⁺, Ca²⁺, Mg²⁺)

Answer 9

• Osmotic Balance
• Ionic Gradients
• Neutralization of Charge in Macromolecules

Question 10

What is unique about Iron (Fe) and Copper (Cu)?

Answer 10

• Stable in Two Oxidation States
• Found in Electron Transport Compounds

Question 11

Van Der Waals Interaction

Answer 11

A short-range attractive force between uncharged chemical groups that are in close proximity.

Question 12

What helps to stabilize the electrostatic repulsion between phosphoryl groups in DNA?

Answer 12

Positive Ions

Question 13

Which molecular interactions contribute to base-stacking in DNA?

Answer 13

• Van Der Waals Interactions
• Hydrophobic Interactions

Question 14

How do metabolic acids impact physiological pH?

Answer 14

Metabolic acids deplete the amount of base (A^–) present in bodily fluids.

Question 15

What type of function is ΔG?

Answer 15

State Function

ΔG is based solely on the starting conditions and the ending conditions of a system (and not on a rate of the reaction).

Question 16

What is ΔG an expression for?

Answer 16

The magnitude of the driving force causing a system to reach equilibrium.

Question 17

Standard Conditions

Answer 17

• 1 atm
• 25 °C
• pH = 7
• [H₂O] = 55.5 M
• [Mg²⁺] = 1.0 mM

Question 18

Gas Constant (R)

Answer 18

• 8.315 J/mol·K
• 0.008315 kJ/mol·K.

Question 19

ΔG° → K_eq

Answer 19

ΔG° = –RTln(K_eq)

Question 20

ΔG → Q

Answer 20

ΔG = ΔG° + RTln(Q)

Question 21

Relationship: ΔG° and K_eq

Answer 21

• K_eq = 1: ΔG° is 0 (At Equilibrium)
• K_eq > 1: ΔG° is Negative (Products Favored)
• K_eq < 1: ΔG° is Positive (Reactants Favored)

Question 22

Why are the products of ATP hydrolysis more thermodynamically favorable than ATP itself?

Answer 22

• Greater Solvation
• Better Charge Separation
• Greater Resonance Stabilization