21．蛋白質(zhì)分子中的平均含氮量為（  ）
A.6.25％                                                              B.16％
C.18％                                                                  D.19％
22．在三羧酸循環(huán)中，催化底物水平磷酸化的反應(yīng)是（     ）
A.琥珀酰輔酶 A→琥珀酸                                 B.檸檬酸→異檸檬酸
C.α-酮戊二酸→琥珀酰輔酶 A                         D.蘋(píng)果酸→草酰乙酸
23．糖原合成中，葡萄糖的活化需要（     ）
A.ATP                                                                 B.CTP
C.GTP                                                                  D.UTP
24．酮體生成的原料是（   ）
A.乙酰乙酸                                                          B.乙酰輔酶 A
C.乙酰乙酰輔酶 A                                             D.β-羥基β-甲基戊二酸單酰輔酶 A
25．下述氨基酸中屬于必需氨基酸的是（ ）
A.丙氨酸                                                              B.谷氨酸
C.絲氨酸                                                              D.苯丙氨酸
26．在蛋白質(zhì)生物合成中具有轉(zhuǎn)運(yùn)氨基酸作用的 RNA 是（  ）
A.mRNA                                                             B.rRNA
C.HnRNA                                                           D.tRNA
27.調(diào)節(jié)體內(nèi)無(wú)機(jī)鹽代謝的激素是（ ）
A.抗利尿激素                                                      B.醛固酮
C.皮質(zhì)醇                                                              D.血管緊張素
28.人體血漿中緩沖容量最大的緩沖對(duì)是（       ）
A.NaHCO3/H2CO3                                                                                         B.KHCO3/H2CO3
C.Na2HPO4/NaH2PO4                                                                               D.K2HPO4/KH2PO4
29.若 Km=1 mmol/L，當(dāng) V=98%Vmax 時(shí)，［S］等于（     ）
A.33 mmol/L                                                      B.49 mmol/L
C.53 mmol/L                                                      D.69 mmol/L
30．下列既可以生糖又可以生酮的氨基酸是（       ）
A.亮氨酸                                                              B.賴(lài)氨酸
C.苯丙氨酸                                                          D.絲氨酸
二、多項(xiàng)選擇題(本大題共 5 小題，每小題 2 分，共 10 分)
在每小題列出的五個(gè)備選項(xiàng)中至少有兩個(gè)是符合題目要求的，請(qǐng)將其代碼填寫(xiě)在題后的括號(hào)內(nèi)。錯(cuò)選、
多選、少選或未選均無(wú)分。
31.肝臟在糖代謝中的重要作用有（     ）
A.糖原合成                                                         B.糖異生
C.調(diào)節(jié)血糖                                                         D.磷酸戊糖途徑
E.合成脂肪 
32.影響血紅蛋白與氧結(jié)合的因素有（     ）
A.呼吸頻率                                                          B.呼吸深淺
C.氧分壓                                                              D.2,3-DPG
E.Bohr 效應(yīng)
33.血漿中的緩沖對(duì)有（        ）
A.碳酸氫鹽緩沖對(duì)                                              B.磷酸鹽緩沖對(duì)
C.血漿蛋白緩沖對(duì)                                              D.硫酸鹽緩沖對(duì)
E.血紅蛋白緩沖對(duì)
34．人體內(nèi)常量元素有（        ）
A.銅                                                                      B.鎂
C.氟                                                                      D.磷
E.錳
35．現(xiàn)知人體第二信使有（        ）
A.cAMP                                                              B.cGMP
C.鈣離子                                                              D.cTMP
E.cUMP