Question 1

Which property of DNA is fundamental to the process of nucleic acid hybridization, which underlies most genetic engineering techniques?

Accepted Answer

The complementary base pairing between DNA strands

Question 2

A scientist wants to clone a gene from a eukaryotic organism. Which of the following steps is essential for creating a recombinant plasmid containing this gene?

Accepted Answer

Digesting both the plasmid and the gene of interest with the same restriction enzyme

Question 3

What is the role of DNA ligase in the formation of recombinant DNA molecules?

Accepted Answer

It seals the sugar-phosphate backbone between DNA fragments

Question 4

Which of the following best describes a 'cloning vector'?

Accepted Answer

A DNA molecule that can carry foreign DNA into a host cell and replicate there

Question 5

A restriction enzyme recognizes the sequence $$5'-GAATTC-3'$$ and cuts between G and A. What type of ends are produced and why are they useful in genetic engineering?

Accepted Answer

Sticky ends; they can form hydrogen bonds with complementary sequences

Question 6

Which technique is used to separate DNA fragments by size for analysis after restriction digestion?

Accepted Answer

Gel electrophoresis

Question 7

During PCR, what is the function of the primers?

Accepted Answer

They provide a starting point for DNA polymerase to synthesize new DNA strands

Question 8

Why is Taq polymerase used in PCR instead of a typical DNA polymerase?

Accepted Answer

It is resistant to high temperatures used during the denaturation step

Question 9

If a PCR reaction is run for 20 cycles, how many copies of the target DNA sequence are theoretically produced from a single starting molecule? Use the formula $$2^n$$, where $$n is $$the number of cycles.

Accepted Answer

$$2^{20} = 1$$,048,576$$

Question 10

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

Accepted Answer

Producing human growth hormone in bacteria for medical use

Question 11

A researcher wants to amplify a gene from a woolly mammoth fossil. Which technique would be most appropriate?

Accepted Answer

Polymerase chain reaction (PCR)

Question 12

Which of the following statements about CRISPR-Cas9 is correct?

Accepted Answer

Cas9 uses a guide RNA to target and cut specific DNA sequences

Question 13

In the context of gene editing, what is a 'gene drive'?

Accepted Answer

A strategy to bias inheritance so an engineered gene spreads rapidly through a population

Question 14

Which of the following best explains why PCR cannot fully replace gene cloning in cells for producing large amounts of a gene?

Accepted Answer

PCR can introduce errors and is limited in the length of DNA it can accurately copy

Question 15

Which of the following is a key difference between next-generation and third-generation DNA sequencing techniques?

Accepted Answer

Next-generation sequencing requires DNA amplification, while third-generation can sequence single molecules without amplification

Question 16

A restriction enzyme cuts the sequence $$5'-CGA\underline{T}CG-3'$$ between T and C. What type of bond is being cleaved?

Accepted Answer

Phosphodiester bond in the sugar-phosphate backbone

Question 17

Which of the following is a potential ethical concern associated with CRISPR-Cas9 gene editing?

Accepted Answer

The possibility of off-target effects altering unintended genes

Question 18

In DNA sequencing by synthesis, how is the identity of each nucleotide determined?

Accepted Answer

By the color of the fluorescent tag attached to each nucleotide

Question 19

Which of the following best describes the role of complementary base pairing in CRISPR-Cas9 gene editing?

Accepted Answer

It allows the guide RNA to bind specifically to the target DNA sequence

Question 20

A patient with sickle-cell disease is treated using CRISPR-Cas9 to reactivate fetal hemoglobin. What is the rationale for this approach?

Accepted Answer

Fetal hemoglobin can substitute for defective adult hemoglobin, alleviating disease symptoms

Genetic Engineering: DNA Cloning, PCR, Sequencing, and Gene Editing

Study Guide - Practice Questions

Study Guide - Flashcards