{ "chapter": "Biotechnology", "count": 100, "answerIndex": "zero-based", "notice": "Original practice items including related concept variants; not official examination questions.", "questions": [ { "id": "sticky-ends", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "Why are complementary sticky ends useful when constructing recombinant DNA?", "options": [ "They base-pair and align DNA fragments for ligase", "They translate DNA without ribosomes", "They destroy every plasmid marker", "They prevent all mutation" ], "answer": 0, "explanation": "Complementary single-stranded overhangs hydrogen-bond, holding the fragments in the correct alignment so DNA ligase can seal the sugar–phosphate backbone." }, { "id": "plasmid-selection-marker", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "After bacterial transformation, an antibiotic-resistance gene on the plasmid is used mainly to:", "options": [ "Force the insert to replicate outside cells", "Identify cells that received the plasmid", "Convert the plasmid into a chromosome", "Measure the protein's tertiary structure" ], "answer": 1, "explanation": "Growth on the matching antibiotic selects transformed cells carrying the plasmid. Additional screening may still be needed to confirm that the desired insert is present." }, { "id": "pcr-cycle-order", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "Which sequence correctly orders one PCR cycle?", "options": [ "Extension → denaturation → translation", "Ligation → transcription → annealing", "Denaturation → primer annealing → extension", "Annealing → meiosis → replication" ], "answer": 2, "explanation": "Heat separates the DNA strands, cooling allows primers to anneal, and a thermostable polymerase extends from those primers." }, { "id": "hybridoma-monoclonal", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "Why is an antibody-producing B lymphocyte fused with a myeloma cell during hybridoma production?", "options": [ "To remove antibody specificity", "To create a bacteriophage", "To stop every cell division", "To combine specific antibody production with prolonged cell division" ], "answer": 3, "explanation": "The B cell provides the desired antibody specificity, while the myeloma partner contributes the ability to divide repeatedly in culture." }, { "id": "biotechnology-restriction-outcome", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "A restriction endonuclease recognizes its specific DNA sequence. Which outcome follows most directly?", "options": [ "The DNA backbone is cut at or near that site", "They align by base pairing", "A continuous recombinant DNA backbone forms", "The inserted DNA can be copied as the plasmid replicates" ], "answer": 0, "explanation": "The DNA backbone is cut at or near that site. The enzyme hydrolyses phosphodiester bonds in both strands." }, { "id": "biotechnology-restriction-cause", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "Which change most directly explains this observation: the DNA backbone is cut at or near that site?", "options": [ "Two DNA fragments have complementary sticky ends", "A restriction endonuclease recognizes its specific DNA sequence", "DNA ligase acts on adjacent aligned DNA fragments", "A recombinant plasmid enters a compatible bacterial cell" ], "answer": 1, "explanation": "The DNA backbone is cut at or near that site. The enzyme hydrolyses phosphodiester bonds in both strands." }, { "id": "biotechnology-restriction-mechanism", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "After a restriction endonuclease recognizes its specific DNA sequence, which explanation best links the change to its outcome?", "options": [ "Hydrogen bonds between matching overhangs hold the fragments together for ligation", "The enzyme creates phosphodiester bonds between neighbouring nucleotides", "The enzyme hydrolyses phosphodiester bonds in both strands", "The vector contains an origin of replication recognized by bacterial machinery" ], "answer": 2, "explanation": "The DNA backbone is cut at or near that site. The enzyme hydrolyses phosphodiester bonds in both strands." }, { "id": "biotechnology-sticky-outcome", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "After two DNA fragments have complementary sticky ends, which observation is most likely?", "options": [ "A continuous recombinant DNA backbone forms", "Only cells carrying the resistance-marked plasmid form colonies", "The inserted DNA can be copied as the plasmid replicates", "They align by base pairing" ], "answer": 3, "explanation": "They align by base pairing. Hydrogen bonds between matching overhangs hold the fragments together for ligation." }, { "id": "biotechnology-sticky-cause", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "A learner records that they align by base pairing. Which preceding event best accounts for it?", "options": [ "Two DNA fragments have complementary sticky ends", "A recombinant plasmid enters a compatible bacterial cell", "DNA ligase acts on adjacent aligned DNA fragments", "Transformed bacteria are placed on an antibiotic medium" ], "answer": 0, "explanation": "They align by base pairing. Hydrogen bonds between matching overhangs hold the fragments together for ligation." }, { "id": "biotechnology-sticky-mechanism", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "After two DNA fragments have complementary sticky ends, which explanation best links the change to its outcome?", "options": [ "The enzyme creates phosphodiester bonds between neighbouring nucleotides", "Hydrogen bonds between matching overhangs hold the fragments together for ligation", "The selectable marker permits survival in the presence of the drug", "The vector contains an origin of replication recognized by bacterial machinery" ], "answer": 1, "explanation": "They align by base pairing. Hydrogen bonds between matching overhangs hold the fragments together for ligation." }, { "id": "biotechnology-sticky-integrated", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "Which paired outcome and explanation best follows from this condition: two DNA fragments have complementary sticky ends?", "options": [ "The inserted DNA can be copied as the plasmid replicates — The vector contains an origin of replication recognized by bacterial machinery", "A continuous recombinant DNA backbone forms — The enzyme creates phosphodiester bonds between neighbouring nucleotides", "They align by base pairing — Hydrogen bonds between matching overhangs hold the fragments together for ligation", "Only cells carrying the resistance-marked plasmid form colonies — The selectable marker permits survival in the presence of the drug" ], "answer": 2, "explanation": "They align by base pairing. Hydrogen bonds between matching overhangs hold the fragments together for ligation." }, { "id": "biotechnology-ligase-outcome", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "A student models this change: DNA ligase acts on adjacent aligned DNA fragments. What should the model predict first?", "options": [ "The inserted DNA can be copied as the plasmid replicates", "Only cells carrying the resistance-marked plasmid form colonies", "Millions of copies accumulate", "A continuous recombinant DNA backbone forms" ], "answer": 3, "explanation": "A continuous recombinant DNA backbone forms. The enzyme creates phosphodiester bonds between neighbouring nucleotides." }, { "id": "biotechnology-ligase-cause", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "What is the most likely cause when a continuous recombinant DNA backbone forms?", "options": [ "DNA ligase acts on adjacent aligned DNA fragments", "Transformed bacteria are placed on an antibiotic medium", "A target DNA region undergoes repeated PCR cycles with suitable primers", "A recombinant plasmid enters a compatible bacterial cell" ], "answer": 0, "explanation": "A continuous recombinant DNA backbone forms. The enzyme creates phosphodiester bonds between neighbouring nucleotides." }, { "id": "biotechnology-ligase-mechanism", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "After DNA ligase acts on adjacent aligned DNA fragments, which explanation best links the change to its outcome?", "options": [ "The vector contains an origin of replication recognized by bacterial machinery", "The enzyme creates phosphodiester bonds between neighbouring nucleotides", "The selectable marker permits survival in the presence of the drug", "Denaturation, annealing and extension approximately double the target each efficient cycle" ], "answer": 1, "explanation": "A continuous recombinant DNA backbone forms. The enzyme creates phosphodiester bonds between neighbouring nucleotides." }, { "id": "biotechnology-ligase-integrated", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "Which paired outcome and explanation best follows from this condition: DNA ligase acts on adjacent aligned DNA fragments?", "options": [ "The inserted DNA can be copied as the plasmid replicates — The vector contains an origin of replication recognized by bacterial machinery", "Only cells carrying the resistance-marked plasmid form colonies — The selectable marker permits survival in the presence of the drug", "A continuous recombinant DNA backbone forms — The enzyme creates phosphodiester bonds between neighbouring nucleotides", "Millions of copies accumulate — Denaturation, annealing and extension approximately double the target each efficient cycle" ], "answer": 2, "explanation": "A continuous recombinant DNA backbone forms. The enzyme creates phosphodiester bonds between neighbouring nucleotides." }, { "id": "biotechnology-plasmid-outcome", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "Which immediate result is most consistent with this condition: A recombinant plasmid enters a compatible bacterial cell?", "options": [ "Only cells carrying the resistance-marked plasmid form colonies", "Millions of copies accumulate", "Complementary DNA without introns is produced", "The inserted DNA can be copied as the plasmid replicates" ], "answer": 3, "explanation": "The inserted DNA can be copied as the plasmid replicates. The vector contains an origin of replication recognized by bacterial machinery." }, { "id": "biotechnology-plasmid-cause", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "Which condition would most specifically produce this result: the inserted DNA can be copied as the plasmid replicates?", "options": [ "A recombinant plasmid enters a compatible bacterial cell", "Transformed bacteria are placed on an antibiotic medium", "A target DNA region undergoes repeated PCR cycles with suitable primers", "Mature mRNA is used as a template by reverse transcriptase" ], "answer": 0, "explanation": "The inserted DNA can be copied as the plasmid replicates. The vector contains an origin of replication recognized by bacterial machinery." }, { "id": "biotechnology-plasmid-mechanism", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "After a recombinant plasmid enters a compatible bacterial cell, which explanation best links the change to its outcome?", "options": [ "The selectable marker permits survival in the presence of the drug", "The vector contains an origin of replication recognized by bacterial machinery", "Denaturation, annealing and extension approximately double the target each efficient cycle", "RNA-directed DNA synthesis copies the processed transcript" ], "answer": 1, "explanation": "The inserted DNA can be copied as the plasmid replicates. The vector contains an origin of replication recognized by bacterial machinery." }, { "id": "biotechnology-plasmid-integrated", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "Which paired outcome and explanation best follows from this condition: a recombinant plasmid enters a compatible bacterial cell?", "options": [ "Only cells carrying the resistance-marked plasmid form colonies — The selectable marker permits survival in the presence of the drug", "Millions of copies accumulate — Denaturation, annealing and extension approximately double the target each efficient cycle", "The inserted DNA can be copied as the plasmid replicates — The vector contains an origin of replication recognized by bacterial machinery", "Complementary DNA without introns is produced — RNA-directed DNA synthesis copies the processed transcript" ], "answer": 2, "explanation": "The inserted DNA can be copied as the plasmid replicates. The vector contains an origin of replication recognized by bacterial machinery." }, { "id": "biotechnology-marker-outcome", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "Transformed bacteria are placed on an antibiotic medium. Which outcome follows most directly?", "options": [ "Bacteria can translate the uninterrupted coding region", "Millions of copies accumulate", "Complementary DNA without introns is produced", "Only cells carrying the resistance-marked plasmid form colonies" ], "answer": 3, "explanation": "Only cells carrying the resistance-marked plasmid form colonies. The selectable marker permits survival in the presence of the drug." }, { "id": "biotechnology-marker-cause", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "Which change most directly explains this observation: only cells carrying the resistance-marked plasmid form colonies?", "options": [ "Transformed bacteria are placed on an antibiotic medium", "A target DNA region undergoes repeated PCR cycles with suitable primers", "Mature mRNA is used as a template by reverse transcriptase", "A human coding sequence made from cDNA is expressed in bacteria" ], "answer": 0, "explanation": "Only cells carrying the resistance-marked plasmid form colonies. The selectable marker permits survival in the presence of the drug." }, { "id": "biotechnology-marker-mechanism", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "After transformed bacteria are placed on an antibiotic medium, which explanation best links the change to its outcome?", "options": [ "Denaturation, annealing and extension approximately double the target each efficient cycle", "The selectable marker permits survival in the presence of the drug", "RNA-directed DNA synthesis copies the processed transcript", "The cDNA lacks introns that bacteria cannot remove by splicing" ], "answer": 1, "explanation": "Only cells carrying the resistance-marked plasmid form colonies. The selectable marker permits survival in the presence of the drug." }, { "id": "biotechnology-marker-integrated", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "Which paired outcome and explanation best follows from this condition: transformed bacteria are placed on an antibiotic medium?", "options": [ "Millions of copies accumulate — Denaturation, annealing and extension approximately double the target each efficient cycle", "Complementary DNA without introns is produced — RNA-directed DNA synthesis copies the processed transcript", "Only cells carrying the resistance-marked plasmid form colonies — The selectable marker permits survival in the presence of the drug", "Bacteria can translate the uninterrupted coding region — The cDNA lacks introns that bacteria cannot remove by splicing" ], "answer": 2, "explanation": "Only cells carrying the resistance-marked plasmid form colonies. The selectable marker permits survival in the presence of the drug." }, { "id": "biotechnology-pcr-outcome", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "After a target DNA region undergoes repeated PCR cycles with suitable primers, which observation is most likely?", "options": [ "Complementary DNA without introns is produced", "Amplification is concentrated on that DNA segment", "Bacteria can translate the uninterrupted coding region", "Millions of copies accumulate" ], "answer": 3, "explanation": "Millions of copies accumulate. Denaturation, annealing and extension approximately double the target each efficient cycle." }, { "id": "biotechnology-pcr-cause", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "A learner records that millions of copies accumulate. Which preceding event best accounts for it?", "options": [ "A target DNA region undergoes repeated PCR cycles with suitable primers", "A human coding sequence made from cDNA is expressed in bacteria", "Mature mRNA is used as a template by reverse transcriptase", "PCR primers bind sequences flanking only the desired locus" ], "answer": 0, "explanation": "Millions of copies accumulate. Denaturation, annealing and extension approximately double the target each efficient cycle." }, { "id": "biotechnology-pcr-mechanism", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "After a target DNA region undergoes repeated PCR cycles with suitable primers, which explanation best links the change to its outcome?", "options": [ "RNA-directed DNA synthesis copies the processed transcript", "Denaturation, annealing and extension approximately double the target each efficient cycle", "DNA polymerase extends only from annealed primer three-prime ends", "The cDNA lacks introns that bacteria cannot remove by splicing" ], "answer": 1, "explanation": "Millions of copies accumulate. Denaturation, annealing and extension approximately double the target each efficient cycle." }, { "id": "biotechnology-pcr-integrated", "chapter": "Biotechnology", "difficulty": "Foundation", "stem": "Which paired outcome and explanation best follows from this condition: a target DNA region undergoes repeated PCR cycles with suitable primers?", "options": [ "Bacteria can translate the uninterrupted coding region — The cDNA lacks introns that bacteria cannot remove by splicing", "Complementary DNA without introns is produced — RNA-directed DNA synthesis copies the processed transcript", "Millions of copies accumulate — Denaturation, annealing and extension approximately double the target each efficient cycle", "Amplification is concentrated on that DNA segment — DNA polymerase extends only from annealed primer three-prime ends" ], "answer": 2, "explanation": "Millions of copies accumulate. Denaturation, annealing and extension approximately double the target each efficient cycle." }, { "id": "biotechnology-reverse-transcriptase-outcome", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "A student models this change: Mature mRNA is used as a template by reverse transcriptase. What should the model predict first?", "options": [ "Bacteria can translate the uninterrupted coding region", "Amplification is concentrated on that DNA segment", "The enzyme survives repeated high-temperature denaturation steps", "Complementary DNA without introns is produced" ], "answer": 3, "explanation": "Complementary DNA without introns is produced. RNA-directed DNA synthesis copies the processed transcript." }, { "id": "biotechnology-reverse-transcriptase-cause", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "What is the most likely cause when complementary DNA without introns is produced?", "options": [ "Mature mRNA is used as a template by reverse transcriptase", "PCR primers bind sequences flanking only the desired locus", "A thermostable polymerase is used in PCR", "A human coding sequence made from cDNA is expressed in bacteria" ], "answer": 0, "explanation": "Complementary DNA without introns is produced. RNA-directed DNA synthesis copies the processed transcript." }, { "id": "biotechnology-reverse-transcriptase-mechanism", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "After mature mRNA is used as a template by reverse transcriptase, which explanation best links the change to its outcome?", "options": [ "The cDNA lacks introns that bacteria cannot remove by splicing", "RNA-directed DNA synthesis copies the processed transcript", "DNA polymerase extends only from annealed primer three-prime ends", "Its heat-stable structure avoids replacement after every cycle" ], "answer": 1, "explanation": "Complementary DNA without introns is produced. RNA-directed DNA synthesis copies the processed transcript." }, { "id": "biotechnology-cdna-bacteria-outcome", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "Which immediate result is most consistent with this condition: A human coding sequence made from cDNA is expressed in bacteria?", "options": [ "Amplification is concentrated on that DNA segment", "The enzyme survives repeated high-temperature denaturation steps", "Bacteria can translate the uninterrupted coding region", "Smaller fragments generally migrate farther toward the positive electrode" ], "answer": 2, "explanation": "Bacteria can translate the uninterrupted coding region. The cDNA lacks introns that bacteria cannot remove by splicing." }, { "id": "biotechnology-cdna-bacteria-cause", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "Which condition would most specifically produce this result: bacteria can translate the uninterrupted coding region?", "options": [ "DNA fragments are exposed to an electric field in agarose gel", "PCR primers bind sequences flanking only the desired locus", "A thermostable polymerase is used in PCR", "A human coding sequence made from cDNA is expressed in bacteria" ], "answer": 3, "explanation": "Bacteria can translate the uninterrupted coding region. The cDNA lacks introns that bacteria cannot remove by splicing." }, { "id": "biotechnology-cdna-bacteria-mechanism", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "After a human coding sequence made from cDNA is expressed in bacteria, which explanation best links the change to its outcome?", "options": [ "The cDNA lacks introns that bacteria cannot remove by splicing", "DNA polymerase extends only from annealed primer three-prime ends", "Its heat-stable structure avoids replacement after every cycle", "Negatively charged DNA moves through pores that impede larger molecules more strongly" ], "answer": 0, "explanation": "Bacteria can translate the uninterrupted coding region. The cDNA lacks introns that bacteria cannot remove by splicing." }, { "id": "biotechnology-cdna-bacteria-integrated", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: a human coding sequence made from cDNA is expressed in bacteria?", "options": [ "Amplification is concentrated on that DNA segment — DNA polymerase extends only from annealed primer three-prime ends", "Bacteria can translate the uninterrupted coding region — The cDNA lacks introns that bacteria cannot remove by splicing", "The enzyme survives repeated high-temperature denaturation steps — Its heat-stable structure avoids replacement after every cycle", "Smaller fragments generally migrate farther toward the positive electrode — Negatively charged DNA moves through pores that impede larger molecules more strongly" ], "answer": 1, "explanation": "Bacteria can translate the uninterrupted coding region. The cDNA lacks introns that bacteria cannot remove by splicing." }, { "id": "biotechnology-primer-specific-outcome", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "PCR primers bind sequences flanking only the desired locus. Which outcome follows most directly?", "options": [ "Smaller fragments generally migrate farther toward the positive electrode", "The enzyme survives repeated high-temperature denaturation steps", "Amplification is concentrated on that DNA segment", "The target can be detected by the probe's signal" ], "answer": 2, "explanation": "Amplification is concentrated on that DNA segment. DNA polymerase extends only from annealed primer three-prime ends." }, { "id": "biotechnology-primer-specific-cause", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "Which change most directly explains this observation: amplification is concentrated on that DNA segment?", "options": [ "A thermostable polymerase is used in PCR", "A labelled single-stranded DNA probe meets a complementary target sequence", "DNA fragments are exposed to an electric field in agarose gel", "PCR primers bind sequences flanking only the desired locus" ], "answer": 3, "explanation": "Amplification is concentrated on that DNA segment. DNA polymerase extends only from annealed primer three-prime ends." }, { "id": "biotechnology-primer-specific-mechanism", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "After PCR primers bind sequences flanking only the desired locus, which explanation best links the change to its outcome?", "options": [ "DNA polymerase extends only from annealed primer three-prime ends", "Negatively charged DNA moves through pores that impede larger molecules more strongly", "Its heat-stable structure avoids replacement after every cycle", "Specific base pairing retains the label at the matching location" ], "answer": 0, "explanation": "Amplification is concentrated on that DNA segment. DNA polymerase extends only from annealed primer three-prime ends." }, { "id": "biotechnology-primer-specific-integrated", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: PCR primers bind sequences flanking only the desired locus?", "options": [ "The enzyme survives repeated high-temperature denaturation steps — Its heat-stable structure avoids replacement after every cycle", "Amplification is concentrated on that DNA segment — DNA polymerase extends only from annealed primer three-prime ends", "The target can be detected by the probe's signal — Specific base pairing retains the label at the matching location", "Smaller fragments generally migrate farther toward the positive electrode — Negatively charged DNA moves through pores that impede larger molecules more strongly" ], "answer": 1, "explanation": "Amplification is concentrated on that DNA segment. DNA polymerase extends only from annealed primer three-prime ends." }, { "id": "biotechnology-taq-outcome", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "After a thermostable polymerase is used in PCR, which observation is most likely?", "options": [ "Smaller fragments generally migrate farther toward the positive electrode", "The target can be detected by the probe's signal", "The enzyme survives repeated high-temperature denaturation steps", "Mutations and predicted coding changes can be identified" ], "answer": 2, "explanation": "The enzyme survives repeated high-temperature denaturation steps. Its heat-stable structure avoids replacement after every cycle." }, { "id": "biotechnology-taq-cause", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "A learner records that the enzyme survives repeated high-temperature denaturation steps. Which preceding event best accounts for it?", "options": [ "DNA fragments are exposed to an electric field in agarose gel", "A labelled single-stranded DNA probe meets a complementary target sequence", "The order of bases in a gene is determined", "A thermostable polymerase is used in PCR" ], "answer": 3, "explanation": "The enzyme survives repeated high-temperature denaturation steps. Its heat-stable structure avoids replacement after every cycle." }, { "id": "biotechnology-taq-mechanism", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "After a thermostable polymerase is used in PCR, which explanation best links the change to its outcome?", "options": [ "Its heat-stable structure avoids replacement after every cycle", "Specific base pairing retains the label at the matching location", "Sequence data are aligned with a reference and translated using the genetic code", "Negatively charged DNA moves through pores that impede larger molecules more strongly" ], "answer": 0, "explanation": "The enzyme survives repeated high-temperature denaturation steps. Its heat-stable structure avoids replacement after every cycle." }, { "id": "biotechnology-taq-integrated", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: a thermostable polymerase is used in PCR?", "options": [ "Smaller fragments generally migrate farther toward the positive electrode — Negatively charged DNA moves through pores that impede larger molecules more strongly", "The enzyme survives repeated high-temperature denaturation steps — Its heat-stable structure avoids replacement after every cycle", "The target can be detected by the probe's signal — Specific base pairing retains the label at the matching location", "Mutations and predicted coding changes can be identified — Sequence data are aligned with a reference and translated using the genetic code" ], "answer": 1, "explanation": "The enzyme survives repeated high-temperature denaturation steps. Its heat-stable structure avoids replacement after every cycle." }, { "id": "biotechnology-gel-outcome", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "A student models this change: DNA fragments are exposed to an electric field in agarose gel. What should the model predict first?", "options": [ "The target can be detected by the probe's signal", "Mutations and predicted coding changes can be identified", "Smaller fragments generally migrate farther toward the positive electrode", "Cas nuclease cuts at a defined location" ], "answer": 2, "explanation": "Smaller fragments generally migrate farther toward the positive electrode. Negatively charged DNA moves through pores that impede larger molecules more strongly." }, { "id": "biotechnology-gel-cause", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "What is the most likely cause when smaller fragments generally migrate farther toward the positive electrode?", "options": [ "A labelled single-stranded DNA probe meets a complementary target sequence", "The order of bases in a gene is determined", "A CRISPR guide RNA pairs with its chosen genomic target beside a suitable PAM", "DNA fragments are exposed to an electric field in agarose gel" ], "answer": 3, "explanation": "Smaller fragments generally migrate farther toward the positive electrode. Negatively charged DNA moves through pores that impede larger molecules more strongly." }, { "id": "biotechnology-gel-mechanism", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "After DNA fragments are exposed to an electric field in agarose gel, which explanation best links the change to its outcome?", "options": [ "Negatively charged DNA moves through pores that impede larger molecules more strongly", "Specific base pairing retains the label at the matching location", "Sequence data are aligned with a reference and translated using the genetic code", "RNA-DNA complementarity positions the nuclease for site-specific cleavage" ], "answer": 0, "explanation": "Smaller fragments generally migrate farther toward the positive electrode. Negatively charged DNA moves through pores that impede larger molecules more strongly." }, { "id": "biotechnology-gel-integrated", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: DNA fragments are exposed to an electric field in agarose gel?", "options": [ "The target can be detected by the probe's signal — Specific base pairing retains the label at the matching location", "Smaller fragments generally migrate farther toward the positive electrode — Negatively charged DNA moves through pores that impede larger molecules more strongly", "Mutations and predicted coding changes can be identified — Sequence data are aligned with a reference and translated using the genetic code", "Cas nuclease cuts at a defined location — RNA-DNA complementarity positions the nuclease for site-specific cleavage" ], "answer": 1, "explanation": "Smaller fragments generally migrate farther toward the positive electrode. Negatively charged DNA moves through pores that impede larger molecules more strongly." }, { "id": "biotechnology-probe-outcome", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "Which immediate result is most consistent with this condition: A labelled single-stranded DNA probe meets a complementary target sequence?", "options": [ "Mutations and predicted coding changes can be identified", "Cas nuclease cuts at a defined location", "The target can be detected by the probe's signal", "Small insertions or deletions may disable the gene" ], "answer": 2, "explanation": "The target can be detected by the probe's signal. Specific base pairing retains the label at the matching location." }, { "id": "biotechnology-probe-cause", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "Which condition would most specifically produce this result: the target can be detected by the probe's signal?", "options": [ "Error-prone repair joins a CRISPR-induced double-strand break", "The order of bases in a gene is determined", "A CRISPR guide RNA pairs with its chosen genomic target beside a suitable PAM", "A labelled single-stranded DNA probe meets a complementary target sequence" ], "answer": 3, "explanation": "The target can be detected by the probe's signal. Specific base pairing retains the label at the matching location." }, { "id": "biotechnology-probe-mechanism", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "After a labelled single-stranded DNA probe meets a complementary target sequence, which explanation best links the change to its outcome?", "options": [ "Specific base pairing retains the label at the matching location", "Sequence data are aligned with a reference and translated using the genetic code", "RNA-DNA complementarity positions the nuclease for site-specific cleavage", "Frameshifts or disrupted regulatory sequences arise during non-homologous end joining" ], "answer": 0, "explanation": "The target can be detected by the probe's signal. Specific base pairing retains the label at the matching location." }, { "id": "biotechnology-probe-integrated", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: a labelled single-stranded DNA probe meets a complementary target sequence?", "options": [ "Mutations and predicted coding changes can be identified — Sequence data are aligned with a reference and translated using the genetic code", "The target can be detected by the probe's signal — Specific base pairing retains the label at the matching location", "Cas nuclease cuts at a defined location — RNA-DNA complementarity positions the nuclease for site-specific cleavage", "Small insertions or deletions may disable the gene — Frameshifts or disrupted regulatory sequences arise during non-homologous end joining" ], "answer": 1, "explanation": "The target can be detected by the probe's signal. Specific base pairing retains the label at the matching location." }, { "id": "biotechnology-sequencing-outcome", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "The order of bases in a gene is determined. Which outcome follows most directly?", "options": [ "Small insertions or deletions may disable the gene", "Cas nuclease cuts at a defined location", "Mutations and predicted coding changes can be identified", "The organism can express a new inherited trait" ], "answer": 2, "explanation": "Mutations and predicted coding changes can be identified. Sequence data are aligned with a reference and translated using the genetic code." }, { "id": "biotechnology-sequencing-cause", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "Which change most directly explains this observation: mutations and predicted coding changes can be identified?", "options": [ "A CRISPR guide RNA pairs with its chosen genomic target beside a suitable PAM", "A functional foreign gene is stably inserted into an organism's genome", "Error-prone repair joins a CRISPR-induced double-strand break", "The order of bases in a gene is determined" ], "answer": 3, "explanation": "Mutations and predicted coding changes can be identified. Sequence data are aligned with a reference and translated using the genetic code." }, { "id": "biotechnology-sequencing-mechanism", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "After the order of bases in a gene is determined, which explanation best links the change to its outcome?", "options": [ "Sequence data are aligned with a reference and translated using the genetic code", "Frameshifts or disrupted regulatory sequences arise during non-homologous end joining", "RNA-DNA complementarity positions the nuclease for site-specific cleavage", "The transgene is copied with host DNA and transcribed under appropriate regulatory control" ], "answer": 0, "explanation": "Mutations and predicted coding changes can be identified. Sequence data are aligned with a reference and translated using the genetic code." }, { "id": "biotechnology-crispr-guide-outcome", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "After a CRISPR guide RNA pairs with its chosen genomic target beside a suitable PAM, which observation is most likely?", "options": [ "Small insertions or deletions may disable the gene", "Cas nuclease cuts at a defined location", "The organism can express a new inherited trait", "A uniform population of antibodies with one specificity is obtained" ], "answer": 1, "explanation": "Cas nuclease cuts at a defined location. RNA-DNA complementarity positions the nuclease for site-specific cleavage." }, { "id": "biotechnology-crispr-guide-cause", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "A learner records that cas nuclease cuts at a defined location. Which preceding event best accounts for it?", "options": [ "Error-prone repair joins a CRISPR-induced double-strand break", "A functional foreign gene is stably inserted into an organism's genome", "A CRISPR guide RNA pairs with its chosen genomic target beside a suitable PAM", "One antibody-producing hybridoma clone is expanded" ], "answer": 2, "explanation": "Cas nuclease cuts at a defined location. RNA-DNA complementarity positions the nuclease for site-specific cleavage." }, { "id": "biotechnology-crispr-guide-mechanism", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "After a CRISPR guide RNA pairs with its chosen genomic target beside a suitable PAM, which explanation best links the change to its outcome?", "options": [ "Frameshifts or disrupted regulatory sequences arise during non-homologous end joining", "The transgene is copied with host DNA and transcribed under appropriate regulatory control", "All cells descend from the selected clone and secrete the same immunoglobulin", "RNA-DNA complementarity positions the nuclease for site-specific cleavage" ], "answer": 3, "explanation": "Cas nuclease cuts at a defined location. RNA-DNA complementarity positions the nuclease for site-specific cleavage." }, { "id": "biotechnology-crispr-guide-integrated", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: a CRISPR guide RNA pairs with its chosen genomic target beside a suitable PAM?", "options": [ "Cas nuclease cuts at a defined location — RNA-DNA complementarity positions the nuclease for site-specific cleavage", "Small insertions or deletions may disable the gene — Frameshifts or disrupted regulatory sequences arise during non-homologous end joining", "The organism can express a new inherited trait — The transgene is copied with host DNA and transcribed under appropriate regulatory control", "A uniform population of antibodies with one specificity is obtained — All cells descend from the selected clone and secrete the same immunoglobulin" ], "answer": 0, "explanation": "Cas nuclease cuts at a defined location. RNA-DNA complementarity positions the nuclease for site-specific cleavage." }, { "id": "biotechnology-knockout-outcome", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "A student models this change: Error-prone repair joins a CRISPR-induced double-strand break. What should the model predict first?", "options": [ "The organism can express a new inherited trait", "Small insertions or deletions may disable the gene", "A uniform population of antibodies with one specificity is obtained", "Microbial growth and product yield become more consistent" ], "answer": 1, "explanation": "Small insertions or deletions may disable the gene. Frameshifts or disrupted regulatory sequences arise during non-homologous end joining." }, { "id": "biotechnology-knockout-cause", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "What is the most likely cause when small insertions or deletions may disable the gene?", "options": [ "A functional foreign gene is stably inserted into an organism's genome", "One antibody-producing hybridoma clone is expanded", "Error-prone repair joins a CRISPR-induced double-strand break", "Temperature, pH, oxygen and nutrients are controlled in a bioreactor" ], "answer": 2, "explanation": "Small insertions or deletions may disable the gene. Frameshifts or disrupted regulatory sequences arise during non-homologous end joining." }, { "id": "biotechnology-knockout-mechanism", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "After error-prone repair joins a CRISPR-induced double-strand break, which explanation best links the change to its outcome?", "options": [ "Sensors and feedback maintain conditions near the organism's production optimum", "The transgene is copied with host DNA and transcribed under appropriate regulatory control", "All cells descend from the selected clone and secrete the same immunoglobulin", "Frameshifts or disrupted regulatory sequences arise during non-homologous end joining" ], "answer": 3, "explanation": "Small insertions or deletions may disable the gene. Frameshifts or disrupted regulatory sequences arise during non-homologous end joining." }, { "id": "biotechnology-knockout-integrated", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: error-prone repair joins a CRISPR-induced double-strand break?", "options": [ "Small insertions or deletions may disable the gene — Frameshifts or disrupted regulatory sequences arise during non-homologous end joining", "The organism can express a new inherited trait — The transgene is copied with host DNA and transcribed under appropriate regulatory control", "A uniform population of antibodies with one specificity is obtained — All cells descend from the selected clone and secrete the same immunoglobulin", "Microbial growth and product yield become more consistent — Sensors and feedback maintain conditions near the organism's production optimum" ], "answer": 0, "explanation": "Small insertions or deletions may disable the gene. Frameshifts or disrupted regulatory sequences arise during non-homologous end joining." }, { "id": "biotechnology-transgenic-outcome", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "Which immediate result is most consistent with this condition: A functional foreign gene is stably inserted into an organism's genome?", "options": [ "A uniform population of antibodies with one specificity is obtained", "The organism can express a new inherited trait", "Recombinant colonies lose that marker's normal phenotype", "Microbial growth and product yield become more consistent" ], "answer": 1, "explanation": "The organism can express a new inherited trait. The transgene is copied with host DNA and transcribed under appropriate regulatory control." }, { "id": "biotechnology-transgenic-cause", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "Which condition would most specifically produce this result: the organism can express a new inherited trait?", "options": [ "Temperature, pH, oxygen and nutrients are controlled in a bioreactor", "One antibody-producing hybridoma clone is expanded", "A functional foreign gene is stably inserted into an organism's genome", "Foreign DNA is inserted into a plasmid marker gene" ], "answer": 2, "explanation": "The organism can express a new inherited trait. The transgene is copied with host DNA and transcribed under appropriate regulatory control." }, { "id": "biotechnology-transgenic-mechanism", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "After a functional foreign gene is stably inserted into an organism's genome, which explanation best links the change to its outcome?", "options": [ "All cells descend from the selected clone and secrete the same immunoglobulin", "The insert disrupts the marker's coding sequence and enables screening", "Sensors and feedback maintain conditions near the organism's production optimum", "The transgene is copied with host DNA and transcribed under appropriate regulatory control" ], "answer": 3, "explanation": "The organism can express a new inherited trait. The transgene is copied with host DNA and transcribed under appropriate regulatory control." }, { "id": "biotechnology-transgenic-integrated", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: a functional foreign gene is stably inserted into an organism's genome?", "options": [ "The organism can express a new inherited trait — The transgene is copied with host DNA and transcribed under appropriate regulatory control", "Microbial growth and product yield become more consistent — Sensors and feedback maintain conditions near the organism's production optimum", "A uniform population of antibodies with one specificity is obtained — All cells descend from the selected clone and secrete the same immunoglobulin", "Recombinant colonies lose that marker's normal phenotype — The insert disrupts the marker's coding sequence and enables screening" ], "answer": 0, "explanation": "The organism can express a new inherited trait. The transgene is copied with host DNA and transcribed under appropriate regulatory control." }, { "id": "biotechnology-monoclonal-outcome", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "One antibody-producing hybridoma clone is expanded. Which outcome follows most directly?", "options": [ "Microbial growth and product yield become more consistent", "A uniform population of antibodies with one specificity is obtained", "Recombinant colonies lose that marker's normal phenotype", "Starting target abundance can be estimated" ], "answer": 1, "explanation": "A uniform population of antibodies with one specificity is obtained. All cells descend from the selected clone and secrete the same immunoglobulin." }, { "id": "biotechnology-monoclonal-cause", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "Which change most directly explains this observation: a uniform population of antibodies with one specificity is obtained?", "options": [ "Temperature, pH, oxygen and nutrients are controlled in a bioreactor", "Foreign DNA is inserted into a plasmid marker gene", "One antibody-producing hybridoma clone is expanded", "Fluorescence is measured during each PCR cycle" ], "answer": 2, "explanation": "A uniform population of antibodies with one specificity is obtained. All cells descend from the selected clone and secrete the same immunoglobulin." }, { "id": "biotechnology-monoclonal-mechanism", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "After one antibody-producing hybridoma clone is expanded, which explanation best links the change to its outcome?", "options": [ "Sensors and feedback maintain conditions near the organism's production optimum", "The insert disrupts the marker's coding sequence and enables screening", "Samples with more initial template cross a defined fluorescence threshold in fewer cycles", "All cells descend from the selected clone and secrete the same immunoglobulin" ], "answer": 3, "explanation": "A uniform population of antibodies with one specificity is obtained. All cells descend from the selected clone and secrete the same immunoglobulin." }, { "id": "biotechnology-monoclonal-integrated", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: one antibody-producing hybridoma clone is expanded?", "options": [ "A uniform population of antibodies with one specificity is obtained — All cells descend from the selected clone and secrete the same immunoglobulin", "Recombinant colonies lose that marker's normal phenotype — The insert disrupts the marker's coding sequence and enables screening", "Starting target abundance can be estimated — Samples with more initial template cross a defined fluorescence threshold in fewer cycles", "Microbial growth and product yield become more consistent — Sensors and feedback maintain conditions near the organism's production optimum" ], "answer": 0, "explanation": "A uniform population of antibodies with one specificity is obtained. All cells descend from the selected clone and secrete the same immunoglobulin." }, { "id": "biotechnology-fermenter-outcome", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "After temperature, pH, oxygen and nutrients are controlled in a bioreactor, which observation is most likely?", "options": [ "Recombinant colonies lose that marker's normal phenotype", "Microbial growth and product yield become more consistent", "Starting target abundance can be estimated", "CRISPR editing may introduce an unwanted mutation" ], "answer": 1, "explanation": "Microbial growth and product yield become more consistent. Sensors and feedback maintain conditions near the organism's production optimum." }, { "id": "biotechnology-fermenter-cause", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "A learner records that microbial growth and product yield become more consistent. Which preceding event best accounts for it?", "options": [ "Foreign DNA is inserted into a plasmid marker gene", "Fluorescence is measured during each PCR cycle", "Temperature, pH, oxygen and nutrients are controlled in a bioreactor", "A guide RNA also closely matches an unintended genomic site" ], "answer": 2, "explanation": "Microbial growth and product yield become more consistent. Sensors and feedback maintain conditions near the organism's production optimum." }, { "id": "biotechnology-fermenter-mechanism", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "After temperature, pH, oxygen and nutrients are controlled in a bioreactor, which explanation best links the change to its outcome?", "options": [ "The insert disrupts the marker's coding sequence and enables screening", "Samples with more initial template cross a defined fluorescence threshold in fewer cycles", "Imperfect specificity can still recruit the nuclease to similar DNA sequences", "Sensors and feedback maintain conditions near the organism's production optimum" ], "answer": 3, "explanation": "Microbial growth and product yield become more consistent. Sensors and feedback maintain conditions near the organism's production optimum." }, { "id": "biotechnology-fermenter-integrated", "chapter": "Biotechnology", "difficulty": "Standard", "stem": "Which paired outcome and explanation best follows from this condition: temperature, pH, oxygen and nutrients are controlled in a bioreactor?", "options": [ "Microbial growth and product yield become more consistent — Sensors and feedback maintain conditions near the organism's production optimum", "Recombinant colonies lose that marker's normal phenotype — The insert disrupts the marker's coding sequence and enables screening", "Starting target abundance can be estimated — Samples with more initial template cross a defined fluorescence threshold in fewer cycles", "CRISPR editing may introduce an unwanted mutation — Imperfect specificity can still recruit the nuclease to similar DNA sequences" ], "answer": 0, "explanation": "Microbial growth and product yield become more consistent. Sensors and feedback maintain conditions near the organism's production optimum." }, { "id": "biotechnology-insertional-inactivation-outcome", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "A student models this change: Foreign DNA is inserted into a plasmid marker gene. What should the model predict first?", "options": [ "Starting target abundance can be estimated", "Recombinant colonies lose that marker's normal phenotype", "CRISPR editing may introduce an unwanted mutation", "A missing functional protein may be restored" ], "answer": 1, "explanation": "Recombinant colonies lose that marker's normal phenotype. The insert disrupts the marker's coding sequence and enables screening." }, { "id": "biotechnology-insertional-inactivation-cause", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "What is the most likely cause when recombinant colonies lose that marker's normal phenotype?", "options": [ "Fluorescence is measured during each PCR cycle", "A guide RNA also closely matches an unintended genomic site", "Foreign DNA is inserted into a plasmid marker gene", "A therapeutic gene reaches enough target cells and is expressed" ], "answer": 2, "explanation": "Recombinant colonies lose that marker's normal phenotype. The insert disrupts the marker's coding sequence and enables screening." }, { "id": "biotechnology-insertional-inactivation-mechanism", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "After foreign DNA is inserted into a plasmid marker gene, which explanation best links the change to its outcome?", "options": [ "The delivered sequence supplies instructions that compensate for the defective gene", "Samples with more initial template cross a defined fluorescence threshold in fewer cycles", "Imperfect specificity can still recruit the nuclease to similar DNA sequences", "The insert disrupts the marker's coding sequence and enables screening" ], "answer": 3, "explanation": "Recombinant colonies lose that marker's normal phenotype. The insert disrupts the marker's coding sequence and enables screening." }, { "id": "biotechnology-qpcr-outcome", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "Which immediate result is most consistent with this condition: Fluorescence is measured during each PCR cycle?", "options": [ "Starting target abundance can be estimated", "A missing functional protein may be restored", "Relative expression of many genes can be compared", "CRISPR editing may introduce an unwanted mutation" ], "answer": 0, "explanation": "Starting target abundance can be estimated. Samples with more initial template cross a defined fluorescence threshold in fewer cycles." }, { "id": "biotechnology-qpcr-cause", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "Which condition would most specifically produce this result: starting target abundance can be estimated?", "options": [ "A guide RNA also closely matches an unintended genomic site", "Fluorescence is measured during each PCR cycle", "A therapeutic gene reaches enough target cells and is expressed", "Fluorescent cDNA from two samples hybridizes to thousands of immobilized probes" ], "answer": 1, "explanation": "Starting target abundance can be estimated. Samples with more initial template cross a defined fluorescence threshold in fewer cycles." }, { "id": "biotechnology-qpcr-mechanism", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "After fluorescence is measured during each PCR cycle, which explanation best links the change to its outcome?", "options": [ "Imperfect specificity can still recruit the nuclease to similar DNA sequences", "The delivered sequence supplies instructions that compensate for the defective gene", "Samples with more initial template cross a defined fluorescence threshold in fewer cycles", "Signal intensity at each probe reflects the abundance of its complementary transcript" ], "answer": 2, "explanation": "Starting target abundance can be estimated. Samples with more initial template cross a defined fluorescence threshold in fewer cycles." }, { "id": "biotechnology-qpcr-integrated", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "Which paired outcome and explanation best follows from this condition: fluorescence is measured during each PCR cycle?", "options": [ "CRISPR editing may introduce an unwanted mutation — Imperfect specificity can still recruit the nuclease to similar DNA sequences", "A missing functional protein may be restored — The delivered sequence supplies instructions that compensate for the defective gene", "Relative expression of many genes can be compared — Signal intensity at each probe reflects the abundance of its complementary transcript", "Starting target abundance can be estimated — Samples with more initial template cross a defined fluorescence threshold in fewer cycles" ], "answer": 3, "explanation": "Starting target abundance can be estimated. Samples with more initial template cross a defined fluorescence threshold in fewer cycles." }, { "id": "biotechnology-off-target-outcome", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "A guide RNA also closely matches an unintended genomic site. Which outcome follows most directly?", "options": [ "CRISPR editing may introduce an unwanted mutation", "A missing functional protein may be restored", "Relative expression of many genes can be compared", "They can differentiate into several specialized cell types" ], "answer": 0, "explanation": "CRISPR editing may introduce an unwanted mutation. Imperfect specificity can still recruit the nuclease to similar DNA sequences." }, { "id": "biotechnology-off-target-cause", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "Which change most directly explains this observation: CRISPR editing may introduce an unwanted mutation?", "options": [ "A therapeutic gene reaches enough target cells and is expressed", "A guide RNA also closely matches an unintended genomic site", "Fluorescent cDNA from two samples hybridizes to thousands of immobilized probes", "Pluripotent stem cells receive controlled developmental signals" ], "answer": 1, "explanation": "CRISPR editing may introduce an unwanted mutation. Imperfect specificity can still recruit the nuclease to similar DNA sequences." }, { "id": "biotechnology-off-target-mechanism", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "After a guide RNA also closely matches an unintended genomic site, which explanation best links the change to its outcome?", "options": [ "The delivered sequence supplies instructions that compensate for the defective gene", "Signal intensity at each probe reflects the abundance of its complementary transcript", "Imperfect specificity can still recruit the nuclease to similar DNA sequences", "Signalling alters transcription networks while the cells retain broad developmental potential" ], "answer": 2, "explanation": "CRISPR editing may introduce an unwanted mutation. Imperfect specificity can still recruit the nuclease to similar DNA sequences." }, { "id": "biotechnology-off-target-integrated", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "Which paired outcome and explanation best follows from this condition: a guide RNA also closely matches an unintended genomic site?", "options": [ "A missing functional protein may be restored — The delivered sequence supplies instructions that compensate for the defective gene", "Relative expression of many genes can be compared — Signal intensity at each probe reflects the abundance of its complementary transcript", "They can differentiate into several specialized cell types — Signalling alters transcription networks while the cells retain broad developmental potential", "CRISPR editing may introduce an unwanted mutation — Imperfect specificity can still recruit the nuclease to similar DNA sequences" ], "answer": 3, "explanation": "CRISPR editing may introduce an unwanted mutation. Imperfect specificity can still recruit the nuclease to similar DNA sequences." }, { "id": "biotechnology-gene-therapy-outcome", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "After a therapeutic gene reaches enough target cells and is expressed, which observation is most likely?", "options": [ "A missing functional protein may be restored", "Relative expression of many genes can be compared", "They can differentiate into several specialized cell types", "The DNA backbone is cut at or near that site" ], "answer": 0, "explanation": "A missing functional protein may be restored. The delivered sequence supplies instructions that compensate for the defective gene." }, { "id": "biotechnology-gene-therapy-cause", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "A learner records that a missing functional protein may be restored. Which preceding event best accounts for it?", "options": [ "Fluorescent cDNA from two samples hybridizes to thousands of immobilized probes", "A therapeutic gene reaches enough target cells and is expressed", "Pluripotent stem cells receive controlled developmental signals", "A restriction endonuclease recognizes its specific DNA sequence" ], "answer": 1, "explanation": "A missing functional protein may be restored. The delivered sequence supplies instructions that compensate for the defective gene." }, { "id": "biotechnology-gene-therapy-mechanism", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "After a therapeutic gene reaches enough target cells and is expressed, which explanation best links the change to its outcome?", "options": [ "Signal intensity at each probe reflects the abundance of its complementary transcript", "Signalling alters transcription networks while the cells retain broad developmental potential", "The delivered sequence supplies instructions that compensate for the defective gene", "The enzyme hydrolyses phosphodiester bonds in both strands" ], "answer": 2, "explanation": "A missing functional protein may be restored. The delivered sequence supplies instructions that compensate for the defective gene." }, { "id": "biotechnology-gene-therapy-integrated", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "Which paired outcome and explanation best follows from this condition: a therapeutic gene reaches enough target cells and is expressed?", "options": [ "The DNA backbone is cut at or near that site — The enzyme hydrolyses phosphodiester bonds in both strands", "Relative expression of many genes can be compared — Signal intensity at each probe reflects the abundance of its complementary transcript", "They can differentiate into several specialized cell types — Signalling alters transcription networks while the cells retain broad developmental potential", "A missing functional protein may be restored — The delivered sequence supplies instructions that compensate for the defective gene" ], "answer": 3, "explanation": "A missing functional protein may be restored. The delivered sequence supplies instructions that compensate for the defective gene." }, { "id": "biotechnology-microarray-outcome", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "A student models this change: Fluorescent cDNA from two samples hybridizes to thousands of immobilized probes. What should the model predict first?", "options": [ "Relative expression of many genes can be compared", "The DNA backbone is cut at or near that site", "They can differentiate into several specialized cell types", "They align by base pairing" ], "answer": 0, "explanation": "Relative expression of many genes can be compared. Signal intensity at each probe reflects the abundance of its complementary transcript." }, { "id": "biotechnology-microarray-cause", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "What is the most likely cause when relative expression of many genes can be compared?", "options": [ "Pluripotent stem cells receive controlled developmental signals", "Fluorescent cDNA from two samples hybridizes to thousands of immobilized probes", "Two DNA fragments have complementary sticky ends", "A restriction endonuclease recognizes its specific DNA sequence" ], "answer": 1, "explanation": "Relative expression of many genes can be compared. Signal intensity at each probe reflects the abundance of its complementary transcript." }, { "id": "biotechnology-microarray-mechanism", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "After fluorescent cDNA from two samples hybridizes to thousands of immobilized probes, which explanation best links the change to its outcome?", "options": [ "The enzyme hydrolyses phosphodiester bonds in both strands", "Signalling alters transcription networks while the cells retain broad developmental potential", "Signal intensity at each probe reflects the abundance of its complementary transcript", "Hydrogen bonds between matching overhangs hold the fragments together for ligation" ], "answer": 2, "explanation": "Relative expression of many genes can be compared. Signal intensity at each probe reflects the abundance of its complementary transcript." }, { "id": "biotechnology-microarray-integrated", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "Which paired outcome and explanation best follows from this condition: fluorescent cDNA from two samples hybridizes to thousands of immobilized probes?", "options": [ "They can differentiate into several specialized cell types — Signalling alters transcription networks while the cells retain broad developmental potential", "They align by base pairing — Hydrogen bonds between matching overhangs hold the fragments together for ligation", "The DNA backbone is cut at or near that site — The enzyme hydrolyses phosphodiester bonds in both strands", "Relative expression of many genes can be compared — Signal intensity at each probe reflects the abundance of its complementary transcript" ], "answer": 3, "explanation": "Relative expression of many genes can be compared. Signal intensity at each probe reflects the abundance of its complementary transcript." }, { "id": "biotechnology-stem-cells-outcome", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "Which immediate result is most consistent with this condition: Pluripotent stem cells receive controlled developmental signals?", "options": [ "They can differentiate into several specialized cell types", "They align by base pairing", "A continuous recombinant DNA backbone forms", "The DNA backbone is cut at or near that site" ], "answer": 0, "explanation": "They can differentiate into several specialized cell types. Signalling alters transcription networks while the cells retain broad developmental potential." }, { "id": "biotechnology-stem-cells-cause", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "Which condition would most specifically produce this result: they can differentiate into several specialized cell types?", "options": [ "A restriction endonuclease recognizes its specific DNA sequence", "Pluripotent stem cells receive controlled developmental signals", "Two DNA fragments have complementary sticky ends", "DNA ligase acts on adjacent aligned DNA fragments" ], "answer": 1, "explanation": "They can differentiate into several specialized cell types. Signalling alters transcription networks while the cells retain broad developmental potential." }, { "id": "biotechnology-stem-cells-mechanism", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "After pluripotent stem cells receive controlled developmental signals, which explanation best links the change to its outcome?", "options": [ "The enzyme hydrolyses phosphodiester bonds in both strands", "Hydrogen bonds between matching overhangs hold the fragments together for ligation", "Signalling alters transcription networks while the cells retain broad developmental potential", "The enzyme creates phosphodiester bonds between neighbouring nucleotides" ], "answer": 2, "explanation": "They can differentiate into several specialized cell types. Signalling alters transcription networks while the cells retain broad developmental potential." }, { "id": "biotechnology-stem-cells-integrated", "chapter": "Biotechnology", "difficulty": "Challenge", "stem": "Which paired outcome and explanation best follows from this condition: pluripotent stem cells receive controlled developmental signals?", "options": [ "The DNA backbone is cut at or near that site — The enzyme hydrolyses phosphodiester bonds in both strands", "They align by base pairing — Hydrogen bonds between matching overhangs hold the fragments together for ligation", "A continuous recombinant DNA backbone forms — The enzyme creates phosphodiester bonds between neighbouring nucleotides", "They can differentiate into several specialized cell types — Signalling alters transcription networks while the cells retain broad developmental potential" ], "answer": 3, "explanation": "They can differentiate into several specialized cell types. Signalling alters transcription networks while the cells retain broad developmental potential." }, { "chapter": "Biotechnology", "id": "applied-pcr-count", "difficulty": "Standard", "stem": "Starting with 5 double-stranded DNA molecules, an ideal PCR doubles the target each cycle. How many target molecules are present after 6 cycles?", "options": [ "320", "64", "160", "30" ], "answer": 0, "explanation": "Ideal amplification follows N = N₀×2ⁿ. Here, 5×2⁶ = 320. Real reactions may amplify less efficiently and eventually reach a plateau." }, { "chapter": "Biotechnology", "id": "applied-gel-order", "difficulty": "Foundation", "stem": "Which DNA fragment is expected to migrate farthest from the wells in a standard agarose gel when other conditions are the same?", "options": [ "900 base pairs", "300 base pairs", "1,800 base pairs", "3,000 base pairs" ], "answer": 1, "explanation": "Smaller DNA fragments generally move more easily through the gel matrix. DNA migrates towards the positive electrode because of its negatively charged phosphate backbone." }, { "chapter": "Biotechnology", "id": "applied-screening-insert", "difficulty": "Challenge", "stem": "A plasmid carries ampicillin resistance. Colonies grow on ampicillin after transformation. What remains unproven by growth alone?", "options": [ "Whether they have produced visible descendants", "Whether they can survive the antibiotic conditions used", "Whether the colonies carry the intended DNA insert", "Whether growth occurred on that plate" ], "answer": 2, "explanation": "Antibiotic selection supports possession or expression of the resistance marker. An empty vector can also confer resistance, so the desired insert requires separate screening." }, { "chapter": "Biotechnology", "id": "applied-restriction-map", "difficulty": "Challenge", "stem": "A circular 5,000 bp plasmid has exactly two sites for one restriction enzyme. Complete digestion produces one 1,200 bp fragment. What is the other fragment length?", "options": [ "1,200 bp", "2,500 bp", "5,000 bp", "3,800 bp" ], "answer": 3, "explanation": "Two cuts in circular DNA yield two fragments. Their lengths sum to 5,000 bp, so the other fragment is 5,000 − 1,200 = 3,800 bp." } ] }