Question 1

Which of the following best explains why Thermus aquaticus was critical to the development of PCR?

Accepted Answer

It produces a DNA polymerase that is stable at high temperatures, allowing repeated denaturation and synthesis cycles.

Question 2

During a standard PCR reaction, which step immediately follows denaturation?

Accepted Answer

Primer annealing (hybridization/annealing)

Question 3

If you start with a single double-stranded DNA molecule, how many copies will you have after 5 complete PCR cycles? Use the formula $$N = N_0$ 	imes 2^n$$, where $$N_0 is $$the initial number of molecules and $$n is $$the number of cycles.

Accepted Answer

$$32$$

Question 4

Which of the following is a key difference between RT-PCR and standard PCR?

Accepted Answer

RT-PCR uses reverse transcriptase to convert mRNA into cDNA before amplification.

Question 5

A researcher wants to quantify the expression of a specific gene in different tissues. Which technique should they use and why?

Accepted Answer

qPCR, because it allows real-time quantification of gene expression by measuring fluorescence during amplification.

Question 6

Which of the following statements about SYBR Green in qPCR is correct?

Accepted Answer

SYBR Green fluoresces when bound to double-stranded DNA, allowing quantification of PCR products in real time.

Question 7

Which blotting technique would you use to detect the presence of a specific mRNA in a tissue sample?

Accepted Answer

Northern blot

Question 8

A scientist is interested in visualizing where a particular mRNA is expressed within a developing embryo. Which technique should they use?

Accepted Answer

RNA in situ hybridization

Question 9

What is the main purpose of using a secondary antibody conjugated with a fluorescent molecule in immunohistochemistry?

Accepted Answer

To visualize the location of the primary antibody bound to the target protein using fluorescence microscopy.

Question 10

Which of the following best describes the main advantage of RNA sequencing (RNA-seq) over qPCR for studying gene expression?

Accepted Answer

RNA-seq can analyze the expression of all genes in a sample simultaneously, while qPCR is limited to specific target genes.

Question 11

In Sanger sequencing, what is the role of dideoxynucleotides (ddNTPs)?

Accepted Answer

They terminate DNA synthesis at specific bases, allowing determination of the DNA sequence.

Question 12

A researcher wants to compare the transcriptomes of liver and brain tissue in mice. Which technique should they use?

Accepted Answer

RNA sequencing (RNA-seq)

Question 13

Which of the following is a correct statement about the exponential amplification of DNA during PCR?

Accepted Answer

The amount of DNA doubles with each cycle, following the formula $$N = N_0$ 	imes 2^n.$$

Question 14

Which of the following is NOT a step in the standard PCR cycle?

Accepted Answer

Protein denaturation

Question 15

A patient sample contains a very low amount of viral RNA. Which technique would allow you to detect and quantify this RNA most sensitively?

Accepted Answer

RT-qPCR (reverse transcription quantitative PCR)

Question 16

Which of the following best explains why next-generation sequencing (NGS) is preferred over Sanger sequencing for whole-genome projects?

Accepted Answer

NGS can sequence millions of DNA fragments in parallel, making it much faster and more cost-effective for large genomes.

Question 17

Which of the following is a real-world application of PCR?

Accepted Answer

Detecting genetic mutations associated with cancer in patient samples.

Question 18

A scientist uses immunohistochemistry to study a protein in zebrafish retina. What is the role of DAB (diaminobenzoate) in this experiment?

Accepted Answer

DAB is converted by peroxidase into a colored precipitate, marking the location of the target protein.

Question 19

Which of the following best describes a transcriptome?

Accepted Answer

The complete set of RNA transcripts produced by the genome at a specific time in a cell or organism.

Question 20

Which of the following is a key contrast between qPCR and RNA in situ hybridization?

Accepted Answer

qPCR quantifies gene expression levels, while RNA in situ hybridization shows spatial localization of gene expression.

Chapter 20

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