The Solution for GRE Biochemistry Practice Test [120-138]
추천글 : 【GRE】 Solution for GRE Biology Practice Test
Questions 120-122 refer to the following stages of the cell cycle.
120. Actin interaction with myosin is essential.
⑴ answer: E
⑵ 세포질 분열(cytokinesis)
121. Kinetochores are paired and possess microtubules of equal length.
⑴ answer: C
⑵ 중기(metaphase) : equal length로 인해 염색체가 적도판에 배열됨
122. Microtubule depolymerization is essential.
⑴ answer: D
⑵ 후기(anaphase) : 미세소관을 탈중합시킴으로써 적도판에서 각 딸세포로 염색체를 이동시킴
Questions 123-126 refer to the following.
123. A metallo-enzyme that catalyzes the conversion of molecular nitrogen to two molecules of ammonia
⑴ answer: C
124. A key regulatory enzyme in the Calvin cycle
⑴ answer: A
⑵ Rubisco
125. An enzyme whose product serves as a precursor for the biosynthesis of both purine and pyrimidine nucleotides
⑴ answer: E
126. An enzyme in the urea cycle whose product is urea
⑴ answer: B
Questions 127-128 refer to the following.
127. Used to analyze proteins associated with specific DNA sequences
⑴ answer: A
⑵ ChIP-seq
128. Used to alter the expression of specific genes in eukaryotic cells
⑴ answer: B
⑵ RNA 간섭
Questions 129-131 refer to the following amino acids.
129. The amino acid that would contribute most to protein absorption at 280 nm
⑴ answer: B
⑵ 페닐기 포함 아미노산 (280 nm 흡광도) : Phe, Trp, Tyr
130. The amino acid that would be expected to be located within the interior of a folded protein suspended in an aqueous buffer
⑴ answer: E
⑵ 소수성 아미노산 : Ala, Ile, Leu, Met, Phe, Pro, Trp, Val, Gly
131. The amino acid that would disrupt the ordered structure of a folded α-helix
⑴ answer: A
⑵ 프롤린은 단단한 고리 구조 때문에 kink를 만들고, α-나선의 수소결합에 필요한 정상적인 주사슬 N–H가 없기 때문에 α-나선 구조를 방해
⑶ 콜라겐의 구조와도 관련 있음
① 콜라겐의 알파 체인은 글리신, 프롤린, 하이드로프롤린으로 구성
② 각 α 체인은 왼나선 : 원래 α 체인은 오른나선인데 프롤린이 오른나선을 방해
⑷ 결론 : proline은 일반 α-helix에서는 helix breaker지만, collagen triple helix에서는 구조 안정화에 중요한 역할을 함
Questions 132-135 refer to the following.
132. A common structural motif found in the DNA binding domains of transcriptional activators
⑴ answer: A
① helix-turn-helix motif : 두 개의 알파나선, CAP·오페론 작동 부위 등
② zinc finger motif : 스테로이드 호르몬에서 관찰
③ leucine zipper motif (예 : AP-1는 포유동물의 세포생장과 분열에 관여)
④ helix-loop-helix motif
133. A retroviral sequence element
⑴ answer: D
134. A structural motif in transcriptional activator proteins that interacts with proteins in the general transcription apparatus
⑴ answer: B
135. The structure of a transcriptional attenuator
⑴ answer: E
⑵ 헤어핀 구조와 감쇄 조절기작(attenuator)
Questions 136-138
A cell line is transfected with a plasmid encoding either a secreted glycoprotein, X, or a variant of X that contains the amino acids KDEL at its C terminus, both of them under control of an inducible promoter. KDEL motifs are normally found on proteins located in the lumen of the ER. At 30 minutes after induction, cycloheximide, an inhibitor of protein synthesis, is added to the culture medium. At 30, 45, and 60 minutes after induction (that is, 0, 15, or 30 min in cycloheximide), the cells are lysed, rough microsomes are isolated and solubilized, and X or X-KDEL is immunoprecipitated from the solubilized material and run on SDS-PAGE gels. The following gels are obtained.
136. The most likely reason why there is less material in lanes 2 and 3 than there is in lane 1 is that protein X
⑴ answer: D
⑵ 왼쪽 그림에서 보여지는 단백질 밴드는 rough microsome, 즉 ER 내부에 있는 단백질
137. The most likely explanation for the additional bands seen in lanes 5 and 6 is that
⑴ answer: D
138. If cycloheximide had been omitted from the experiment, then
⑴ answer: E
Questions 139-141
A series of chemical compounds have properties that suggest they would interfere with chloroplast function. The effects of the compounds have been tested using illuminated suspensions of isolated chloroplasts and measuring the rates of ATP synthesis and O2 production. The results are shown below with the arrow indicating time of addition of the compound.
139. Which of the following statements is true for the chloroplasts treated with compound A?
⑴ answer: B
⑵ 짝풀림제 : 오히려 전자전달을 증가시키기 위해 산소 생성량이 증가할 수 있음 (보상작용)
140. Which of the following compounds appear(s) to act by blocking noncyclic photophosphorylation while leaving cyclic photophosphorylation unaffected?
⑴ answer: C
⑵ 순환적 광인산화는 정상이므로 ATP 생성량이 어느 정도는 남아 있어야 함
⑶ C의 경우 비순환적 광인산화가 중단되어 전자전달이 막혀서 더이상 산소도 생성되지 못함
141. Isolated chloroplast suspensions can be induced to make ATP in the dark for a short period by incubating them in a low-pH solution and then rapidly transferring them to a high-pH solution. If subjected to such a procedure, chloroplasts would be expected to make ATP if they were first treated with which of the following compounds?
⑴ answer: E
⑵ 이 경우 틸라코이드 내부의 수소이온이 높아지게 되어 자연스럽게 수소이온 농도기울기가 형성됨
⑶ 짝풀림제인 A를 제외하고는 모두 ATP 생성이 예상됨
입력: 2026.04.30 23:21
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