Question 1

Which of the following best describes the role of Taq polymerase in the Polymerase Chain Reaction (PCR)?

Accepted Answer

It synthesizes new DNA strands by adding nucleotides to a primer during repeated heating and cooling cycles.

Question 2

A scientist wants to determine the amount of a specific mRNA in a tissue sample. Which technique would be most appropriate?

Accepted Answer

Quantitative reverse transcription PCR (qRT-PCR)

Question 3

Which of the following statements about Sanger sequencing is correct?

Accepted Answer

It relies on chain-terminating dideoxynucleotides to generate DNA fragments of varying lengths.

Question 4

A researcher uses restriction enzymes to cut a plasmid and insert a gene of interest. What is the primary function of these enzymes in this process?

Accepted Answer

To cleave DNA at specific nucleotide sequences, creating sticky or blunt ends for cloning.

Question 5

Which of the following best explains why Taq polymerase is essential for PCR?

Accepted Answer

It is resistant to high temperatures, allowing repeated denaturation and synthesis cycles.

Question 6

A scientist is comparing gene expression in two different cell types using RNA-seq. What is the main advantage of RNA-seq over traditional DNA microarrays?

Accepted Answer

RNA-seq provides quantitative data and can detect both known and novel transcripts.

Question 7

Which of the following is a key difference between pluripotent and multipotent stem cells?

Accepted Answer

Pluripotent stem cells can differentiate into any cell type in the body, while multipotent stem cells are limited to a specific lineage.

Question 8

A patient receives a bone marrow transplant to treat leukemia. Which biological concept does this procedure best illustrate?

Accepted Answer

Stem cell transplantation using multipotent cells

Question 9

Which of the following best describes a single nucleotide polymorphism (SNP)?

Accepted Answer

A variation at a single base pair in the DNA sequence among individuals.

Question 10

A researcher wants to use CRISPR-Cas9 to knock out a gene in mice. What is the primary function of the Cas9 protein in this process?

Accepted Answer

It introduces double-stranded breaks at specific DNA sequences guided by RNA.

Question 11

Which of the following equations correctly represents the exponential amplification of DNA during PCR, where $$n is $$the number of cycles and $$N_0 is $$the initial number of DNA molecules?

Accepted Answer

$$N = N_0$ 	imes 2^n$$

Question 12

A geneticist is analyzing a disease-causing mutation using DNA sequencing. Which step is essential for distinguishing between a point mutation and a small insertion?

Accepted Answer

Comparing the sequence to a reference genome to identify the exact change in nucleotide(s).

Question 13

Which of the following best explains why restriction enzymes are important tools in molecular cloning?

Accepted Answer

They allow for the precise cutting and pasting of DNA fragments into vectors.

Question 14

A laboratory is using DNA microarrays to study gene expression in cancer cells. What is the main limitation of this technique compared to RNA-seq?

Accepted Answer

Microarrays can only detect genes that are already known and included on the array.

Question 15

Which of the following scenarios best illustrates the use of DNA cloning in biotechnology?

Accepted Answer

Inserting a human insulin gene into bacteria to produce insulin for diabetic patients.

Question 16

A scientist is using PCR to detect a viral infection in a patient. After 30 cycles, the initial amount of viral DNA ($$N_0 = 10$ molecules) is amplified. How many DNA molecules are present after 30 cycles? Use the formula N$$ = $$N_0$$ 	imes 2^n$$.

Accepted Answer

$$N = 10 	imes 2$$^{30}$$ = 10,737,418,240$$

Question 17

Which of the following best describes the purpose of using a plasmid vector in gene cloning?

Accepted Answer

To provide a vehicle for introducing foreign DNA into a host cell for replication and expression.

Question 18

A researcher is studying the function of a gene by creating a knockout mouse. Which technique is most likely used to disrupt the gene's function?

Accepted Answer

CRISPR-Cas9 genome editing

Question 19

Which of the following is a real-world application of therapeutic cloning?

Accepted Answer

Generating patient-specific stem cells for tissue regeneration.

Question 20

A scientist is using DNA sequencing to identify a mutation responsible for a genetic disorder. Which step must occur before sequencing if the gene of interest is present in very low amounts?

Accepted Answer

Amplify the gene using PCR to obtain sufficient DNA for sequencing.

Chapter 20: DNA Sequencing, Gene Expression, and Cloning – Study Guide

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