所屬科目:研究所、轉學考(插大)◆生物化學
1. Which statement MOST COMPLETELY EXPLAINS the large △G° for the hydrolysis of phosphoenolpyruvate? (A)Hydrolysis of the phosphoanhydride bond along with the conversion of the enol to the keto form of pyruvate. (B) The hydrolysis of the phosphoanhydride bond. (C) Conversion from the enol to the keto form of pyruvate. (D) Strong bond energy along with a change in the stereochemistry of the molecule. (E) The large △G° of the phosphoester bond.
4.Which statement is INCORRECT about these amino acids, and amino acid derivatives? (A)GABA (γ-aminobutyric acid) is a potent inhibitory neurotransmitter derived from glutamic acid. (B) Ornithine is an important metabolic intermediate. (C) Epinephrine is a hormone derived from tryptophan. (D) Serotonin is a neurotransmitter derived from tryptophan. (E) Histamine is a neurotransmitter derived from histidine.
9. A β-barrel would most likely be composed of___________ (A) parallel β-sheets connected by regions of a-helix (B) parallel β-sheets connected by β-turns. (C) parallel β-sheets connected by regions of random coil. (D) parallel β-sheets connected disulfide bonds. (E) both a and c are correct.
12. Cellulase is considered a_________. (A) a-(1→4) glucosidase (B) β-(1→4) glucosidase (C) a-(1→6) glucosidase (D) β-(1→4) glucosidase (E) a-(1→1) glucosidase
17. Glycophorin is a membrane protein with: (A) multiple transmembrane segments. (B) most of the mass oriented outside the surface of the cell. (C) about 10% carbohydrate and 90% protein. (D) transmembrane β-barrel segments. (E) All are true
31. All are true for the enzyme-transition state complex EXCEPT: (A) It is designated as . (B) The enzyme stabilizes the transition-state complex more than it stabilizes the substrate complex. (C) The enzyme is "designed" to bind the transition-state structure more tightly than the substrate or product. (D) The energy barrier between ES and is less than the energy barrier between S and . (E) All are true.
36. The T form (tense or taut form) of deoxyhemoglobin differs from oxyhemoglobin (the R form or relaxed form) by all EXCEPT: (A) covalent linkages between subunits. (B) specific intrachain hydrogen bonds. (C) between β-subunit salt links (ion-pair bonds). (D) between a-subunits salt links (ion-pair bonds). (E) intrachain salt bridges.