Question 1

Which of the following best explains why restriction enzymes are essential tools in recombinant DNA technology?

Accepted Answer

They cut DNA at specific palindromic sequences, allowing precise manipulation and joining of DNA fragments from different sources.

Question 2

A researcher wants to clone a 150 kilobase fragment of human DNA. Which vector would be most appropriate for this purpose?

Accepted Answer

Yeast artificial chromosome (YAC)

Question 3

In a blue-white screening experiment, which result indicates that a bacterial colony contains a plasmid with an inserted foreign DNA fragment?

Accepted Answer

The colony appears white on X-gal media.

Question 4

Which of the following statements correctly distinguishes a genomic library from a cDNA library?

Accepted Answer

A genomic library contains all DNA sequences from an organism, while a cDNA library contains only DNA copies of mRNAs present in a cell population.

Question 5

During PCR, which step is responsible for the separation of double-stranded DNA into single strands?

Accepted Answer

Denaturation at $$92-95^\circ C$$

Question 6

A scientist wants to determine whether a specific gene is actively expressed in cancerous tissue. Which technique should they use?

Accepted Answer

Northern blot

Question 7

Which sequencing technology is most likely to have a 15% error rate but allows real-time visualization of nucleotide addition?

Accepted Answer

Third-generation sequencing

Question 8

A knockout mouse is created by inserting a nonfunctional gene flanked by homologous sequences into the genome. What is the primary purpose of this approach?

Accepted Answer

To study the function of a specific gene by observing the effects of its loss

Question 9

Which of the following best describes how the CRISPR-Cas9 system edits a genome?

Accepted Answer

Cas9 is guided by a custom-designed crRNA to a specific DNA sequence, where it creates a double-strand break that is repaired by either nonhomologous end joining (NHEJ) or homologous directed repair (HDR).

Question 10

Which of the following is a potential environmental concern associated with genetically modified (GM) crops?

Accepted Answer

Herbicide-tolerance and insect-resistance genes may be transferred to wild species, potentially disrupting ecosystem diversity.

Question 11

Which method is most suitable for amplifying and analyzing DNA from a very small or degraded forensic sample?

Accepted Answer

STR analysis using PCR

Question 12

A patient is prescribed codeine, which is metabolized by the enzyme CYP2D6. Genetic testing reveals the patient is homozygous for alleles that decrease CYP2D6 activity. What is the most likely clinical consequence?

Accepted Answer

The patient will metabolize codeine too slowly, increasing the risk of overdose.

Question 13

Which of the following statements about microarrays is correct?

Accepted Answer

Microarrays allow simultaneous measurement of expression levels of thousands of genes by hybridizing labeled cDNA to DNA probes on a chip.

Question 14

Which delivery method for gene therapy involves removing cells from a patient, modifying them in the laboratory, and then returning them to the patient?

Accepted Answer

Ex vivo gene therapy

Question 15

Which of the following is a limitation of Y-chromosome STR profiling in forensic analysis?

Accepted Answer

All males with the same paternal lineage have identical Y-STR profiles, making it impossible to distinguish between male relatives.

Question 16

A scientist is using BLAST to compare a newly sequenced gene to known sequences in GenBank. What does a low E-value indicate?

Accepted Answer

The sequences are highly similar and the match is statistically significant.

Question 17

Which of the following best describes the difference between orthologs and paralogs?

Accepted Answer

Orthologs are genes from different species that descended from a common ancestor, while paralogs are homologous genes within the same species.

Question 18

Which of the following is a major ethical concern associated with germ-line gene therapy?

Accepted Answer

Genetic changes will be passed to future generations, affecting individuals who have not given informed consent.

Question 19

Which of the following best describes the main advantage of using STRs over VNTRs in forensic DNA profiling?

Accepted Answer

STRs can be amplified by PCR, allowing analysis of small or degraded samples.

Recombinant DNA Technology, Genomic Analysis, Genetic Engineering, DNA Forensics, and Gene Therapy: Study Guide

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