541. Which of the following is not the hydrophobic and aromatic amino acid?
A. Phenylalanine
B. Tyrosine
C. Tryptophan
D. None of these

542. Stereo chemical configuration of all a-amino acids derived from proteins is
A. L
B. D
C. L and D
D. None of these

543. The α-amino acids have a carboxyl group with a pK around __________ , and an amino group with a pK near __________ .
A. 1.1, and 12.1
B. 6.5, and 8.0
C. 3.3, and 10.5
D. 2.2, and 9.4

544. Coomassie Blue stains the proteins by reacting with
A. arginine residues
B. free c-termini
C. peptide bonds
D. aromatic ring

545. Which amino acid when exposed to ninhydrin produces a brown color?
A. Asparagine
B. Proline
C. Alanine
D. Valine

546. During the unfolding reaction of a helix, breakage of each hydrogen bond requires about 2kJ/mol. This implies hydrogen bonds are
A. much stronger in proteins than in water
B. not reformed with water
C. slightly weaker in proteins than in water
D. slightly stronger in proteins than in water

547. If the enthalpy change for a reaction is zero, ΔG° is equal to
B. -TΔS°
C. -ΔH°
D. lnKeq 

548. Reactions that have positive standard free energy changes (ΔGo> 0) can be made to occur in cells by
A. coupling them with exergonic reactions via a common intermediate
B. manipulating the concentrations of products and reactants such that G/<0
C. coupling them to the hydrolysis of ATP
D. all of the above

549. The Standard Gibb’s free energy, ΔG°, is
A. the residual energy present in the reactants at equilibrium
B. the residual energy present in the products at equilibrium
C. the difference in the residual energy of reactants and products at equilibrium
D. the energy required to convert one mole of reactants to one mole of products

550. If the Standard Gibb’s free energy, ΔG°, for a reaction is positive then
A. the products will be favored
B. the reactants will be favored
C. the concentration of the reactants and products will be equal
D. all of the reactant will be converted to product