49. The role of a metabolite that controls a repressible operon is to
(A) bind to the promoter region and decrease the affinity of RNA polymerase for the promoter.
(B) bind to the operator region and block the attachment of RNA polymerase to the promoter.
(C) increase the production of inactive repressor proteins.
(D) bind to the repressor protein and inactivate it.
(E) bind to the repressor protein and activate it.

45. Insulin resistance causes an increase in gluconeogenic activity in the liver due to the lack of glucose. What serves as the primary carbon source for gluconeogenesis under these conditions? (A) Amino acids. (B) Glycerol. (C) Fructose. (D) Acetyl-CoA. (E) Ketone bodies

46. Considered the following transamination reaction in amino acid biosynthesis, what amino acid would be produced? (A) Glu. (B) Asp. (C) Gln. (D) Asn. (E) Arg.

47. Given the saturated fatty acid shown below, how many ATPs can be produced when it is completely metabolized by β-oxidation? Some useful info:  i. In the TCA cycle, one Acetyl-CoA gives 3 NADHs, 1 FADH2, and 1 GTP. ii. One NADH produces 2.5 ATPs. iii. One FADH2 produces 1.5 ATPs. (A) 50. (B) 52. (C) 60. (D) 62. (E) 64.

48. One of the hopes for use of recent knowledge gained about non-coding RNAs lies with the possibilities for their use in medicine. Of the following scenarios for future research, which would you expect to gain most from RNAs? (A) Exploring a way to turn on the expression of pseudogenes. (B) Targeting siRNAs to disable the expression of an allele associated with autosomal recessive disease. (C) Targeting siRNAs to disable the expression of an allele associated with autosomal dominant disease. (D) Creating knock-out organisms that can be useful for pharmaceutical drug design. (E) Looking for a way to prevent viral DNA from causing infection in humans.

50. A geneticist introduces a transgene into yeast cells and isolates five independent cell lines in which the transgene has integrated into the yeast genome. In four of the lines, the transgene is expressed strongly, but in the fifth there is no expression at all. Which is a likely explanation for the lack of transgene expression in the fifth cell line? (A) A transgene integrated into a heterochromatic region of the genome. (B) A transgene integrated into a euchromatic region of the genome. (C) The transgene was mutated during the process of integration into the host cell genome. (D) The host cell lacks the enzymes necessary to express the transgene. (E) Transgene integrated into a region of the genome characterized by high histone acetylation.

1. 一非揮發性純物質 36.8 公克溶於 208.8 公克的水中而形成理想溶液，測得此溶液在25 C° 時的蒸氣壓為 23.2 mmHg，則上述非揮發性溶質的分子量為多少 ( 公克 / 莫耳 ) ？ ( 已知在25 C° 時，純水的飽和蒸汽壓為 24 mmHg ) (原子量：H=1，O=16) (A) 46 (B) 92 (C) 180 (D) 342

2. 對於下列物質的敘述，何者正確？ (A) 乾冰是化合物 (B) 黃銅為純物質 (C) 水泥是純物質 (D) 混合均勻的糖水是不均勻混合物

3. 某生對含鹼金屬離子或鹼土金屬離子的三個水溶液樣品(都含單一金屬離子)，測其焰色試驗，結果如下： a 樣品：火焰呈黃綠色；  b 樣品：火焰呈黃色； c 樣品：火焰呈紫色； 則下列何者最可能是三個水溶液樣品中所含的金屬離子化合物？ (A) a 含鋇離子化合物，b 含鉀離子化合物，c 含鈉離子化合物 (B) a 含鈣離子化合物，b 含鈉離子化合物，c 含鉀離子化合物 (C) a 含鋇離子化合物，b 含鍶離子化合物，c 含鉀離子化合物 (D) a 含鋇離子化合物，b 含鈉離子化合物，c 含鉀離子化合物

4. 下列有關土壤的敘述，何者正確？ (A) 淨化水質是土壤功能之一 (B) 土壤污染中，來自空氣污染物最嚴重，約佔 80% (C) 矽是地殼中含量最多的元素 (D) 酸雨降下，對土壤不會有影響，因為最後流入河中

5. 定溫下，在理想狀態，一容器含有 3 莫耳氧氣、2 莫耳氮氣與 1 莫耳二氧化碳，彼此不反應，總壓力為 900mmHg 時，則該容器中氧的分壓是多少(mmHg )？ (A) 450 (B) 300 (C) 200 (D) 150