ACS CP ACS CP Biochemistry & Polymer Chemistry

Question 1

Which type of bond is primarily responsible for the secondary structure (alpha-helix and beta-sheet) of proteins?

Accepted Answer

Hydrogen bonds

Answer

Hydrogen bonds between the backbone amide NH and carbonyl C=O groups stabilize the alpha-helix and beta-sheet secondary structures in proteins.

Question 2

The Michaelis-Menten equation describes the relationship between:

Accepted Answer

Substrate concentration and initial reaction velocity for an enzyme-catalyzed reaction

Answer

The Michaelis-Menten equation v = (Vmax[S])/(Km + [S]) relates the initial reaction velocity to substrate concentration, with Km as the substrate concentration at half-maximal velocity.

Question 3

Which polymer property describes the distribution of molecular weights in a polymer sample?

Accepted Answer

Polydispersity index (PDI)

Answer

The polydispersity index (PDI = Mw/Mn) describes the breadth of the molecular weight distribution; a PDI of 1.0 indicates a monodisperse (perfectly uniform) polymer.

Question 4

In step-growth polymerization, high molecular weight polymer is obtained only:

Accepted Answer

At very high conversions (>99%) of functional groups

Answer

In step-growth polymerization, molecular weight increases slowly and high MW polymer is only achieved at very high monomer conversion (>99%), as described by the Carothers equation.

Question 5

The ATP hydrolysis reaction (ATP → ADP + Pi) releases approximately how much free energy under standard biological conditions?

Accepted Answer

-7.3 kcal/mol

Answer

ATP hydrolysis releases approximately -7.3 kcal/mol (-30.5 kJ/mol) of free energy under standard conditions, making it the universal energy currency of cells.

(ACS CP) American Chemical Society (ACS) Certified Professional Practice Test

(ACS CP) American Chemical Society (ACS) Certified Professional Practice Test

ACS CP ACS CP Biochemistry & Polymer Chemistry