80. RNA interference is a mechanism of posttranscriptional RNA-dependent __________.
(A) apoptosis
(B) chromatin-remodeling
(C) coactivation
(D) gene silencing
(E) histone methylation

81. In quantitative RT-PCR for SARS-CoV-2 detection, two patient samples are analyzed. Sample A has a Ct value of 22, while Sample B has a Ct value of 30. Assuming equal amplification efficiency, which statement best describes the relative viral loads in these samples? (A) Sample A has approximately 2-fold higher viral load than Sample B (B) Sample A has approximately 8-fold higher viral load than Sample B (C) Sample B has approximately 100-fold higher viral load than Sample A (D) Sample A has approximately 256-fold higher viral load than Sample B (E) Viral loads cannot be compared using Ct values

82. A researcher studying epigenetic changes in colorectal cancer identifies hypermethylation of the MLH1 gene promoter, leading to loss of DNA mismatch repair function. This methylation occurs at the 5-position of cytosine residues within CpG dinucleotides. Which molecule serves as the methyl group donor for this reaction? (A) Methylcobalamin (B) N5-Methyl-THF (C) S-Adenosylmethionine (D) Betaine (E) Choline

83. Human somatic cells in culture stop dividing after approximately 50 to 60 population doublings, known as the Hayflick limit. This replicative senescence is associated with the progressive shortening of the ends of chromosomes. Which enzymatic activity is normally suppressed in most somatic cells but reactivated in cancer cells and could prevent this shortening? (A) DNA ligase (B) Primase (C) Topoisomerase (D) 3' to 5' exonuclease activity of DNA polymerase (E) Reverse transcriptase activity of telomerase

84. Isoform A of LDH has Km = 0.1 mM and kcat = 500 s-1. Isoform B has Km = 0.5 mM and kcat = 1000 s-1. When substrate concentration is 10 mM, which statement is correct? (A) Isoform A is more efficient because kcat/Km is higher. (B) Isoform B is faster because both enzymes are saturated and Isoform B has higher kcat. (C) Isoform A is faster because it reaches saturation at lower substrate concentration. (D) Both isoforms have equal reaction rates because substrate is in excess. (E) Efficiency cannot be compared without knowing enzyme concentrations.

85. Researchers used CRISPR-Cas9 to generate a gene knockout clone in mammalian cells. After transfection with Cas9 and sgRNA targeting exon 3 of a gene of interest, they observed frameshift mutations in the target region. Which DNA repair pathway is primarily responsible for generating these frameshift mutations? (A) Base excision repair (B) Nucleotide excision repair (C) Mismatch repair (D) Homology-directed repair (E) Non-homologous end joining

86. Mechanical strain in the heart leads to the transcriptional activation of the NPPB gene. This process involves the recruitment of specific transcription factors to the promoter region. Which of the following best describes the initial event in this biochemical signaling cascade? (A) Activation of mechanosensitive ion channels and protein kinase signaling (B) Direct binding of sodium ions to the DNA promoter (C) Inhibition of RNA polymerase II (D) Dephosphorylation of histone tails (E) Export of mature mRNA through nuclear pores

87. A researcher is purifying a 150 kDa protein complex using size-exclusion chromatography. The column is calibrated with standard proteins: thyroglobulin (669 kDa), ferritin (440 kDa), aldolase (158 kDa), and ovalbumin (44 kDa). The void volume (Vo) is 8 mL and the total column volume (Vt) is 24 mL. If the target complex elutes at 14 mL, which statement is correct? (A) The complex is eluted near the Vo, indicating it is larger than 669 kDa. (B) The complex elutes at a volume consistent with its 150 kDa mass, confirming it is in its monomeric/native form. (C) The complex elutes later than ovalbumin (44 kDa), suggesting it is a small peptide. (D) The complex is completely excluded, meaning it is larger than the pore size of the gel. (E) The elution at 14 mL indicates the column is packed incorrectly.

88. Glucose-6-phosphatase is a key regulatory enzyme localized in the endoplasmic reticulum membrane. In von Gierke disease, the deficiency of this enzyme prevents the hydrolysis of glucose-6-phosphate. Which of the following biochemical pathways is/are directly impaired by this deficiency during fasting? (A) Glycogenesis only (B) Glycogenolysis only (C) Gluconeogenesis only (D) Both glycogenolysis and gluconeogenesis (E) The pentose phosphate pathway

89. The figure below shows the absorbance curve at 260 nm of five 100 bp double-stranded DNA fragments (samples A to E) when subjected to heat. DNA denaturation produces a hyperchromic effect. Which sample has the highest G-C content, according to this graph? (A) A (B) B (C) C (D) D (E) E

90. A researcher purified a specific protein and performed structural analysis using two different techniques. The data are as follows: (1) Size-Exclusion Chromatography: Under native (non-denaturing) conditions, the protein elutes at a position corresponding to a molecular weight of 200 kDa; (2) SDS-PAGE (with β-mercaptoethanol): After boiling the sample in SDS and a reducing agent, a single sharp band appears at 50 kDa. Which of the following best describes the native structure of this protein? (A) A monomeric 200 kDa protein that is non-specifically degraded into 50 kDa fragments during electrophoresis (B) A homotetramer composed of four 50 kDa subunits held together by non-covalent interactions or disulfide bonds (C) A homodimer composed of two 100 kDa subunits that were incorrectly measured during chromatography (D) A heterotetramer composed of two 75 kDa subunits and two 25 kDa subunits. (E) A 200 kDa protein that consists of a single polypeptide chain containing four internal protease cleavage sites

115年 - 115 國立中山大學_學士後醫學系招生考試試題：普通生物及生化概論#138369

115年 - 115 學士後醫學系招生考試試題：普通生物及生化概論#138357

115年 - 115 國立清華大學_學士後醫學系單獨招生試題：生物與生化#138208

115年 - 115 國立中興大學_學士後醫學系公費生招生考試：普通生物及生化概論#138023

114年 - 114 學士後醫學系招生考試試題：普通生物及生化概論#126681

114年 - 114 國立中興大學_學士後醫學系公費招生考試：普通生物及生化概論#126435

114年 - 114 國立中山大學_學士後醫學系招生考試試題：普通生物及生化概論#126236

114年 - 114 國立清華大學_學士後醫學系考試︰生物生化#126232

113年 - 113 國立中興大學_學士後醫學系公費招生考試：普通生物及生化概論#119946

113年 - 113 國立清華大學_學士後醫學系招生考試_學士後醫學系：生物及生化#119851