Question 1

Which of the following best describes the process of creating recombinant DNA using a plasmid and a gene of interest?

Accepted Answer

A gene of interest is inserted into a plasmid using restriction enzymes and DNA ligase, forming recombinant DNA that can be introduced into bacteria for cloning.

Question 2

Restriction enzymes are essential tools in genetic engineering. What is their primary function?

Accepted Answer

They cut DNA at specific sequences called restriction sites, producing fragments with sticky or blunt ends.

Question 3

During the polymerase chain reaction (PCR), what is the role of Taq polymerase?

Accepted Answer

It synthesizes new DNA strands by adding nucleotides to primers during the extension step at high temperatures.

Question 4

Which step in PCR is responsible for separating the two strands of DNA?

Accepted Answer

Denaturation

Question 5

A scientist wants to confirm the size of DNA fragments after restriction enzyme digestion. Which technique should they use?

Accepted Answer

Gel electrophoresis

Question 6

In gel electrophoresis, why do smaller DNA fragments move faster through the gel than larger ones?

Accepted Answer

Smaller fragments experience less resistance from the gel matrix, allowing them to migrate more quickly toward the positive electrode.

Question 7

Which of the following equations best represents the exponential amplification of DNA during PCR, where $$n is $$the number of cycles?

Accepted Answer

$$2^n$$

Question 8

A researcher uses a restriction enzyme that recognizes the sequence $$5'	ext{GAATTC}3'$$ and cuts between G and A. What type of ends are produced?

Accepted Answer

Sticky ends with single-stranded overhangs

Question 9

Which of the following is a real-world application of recombinant DNA technology?

Accepted Answer

Producing human insulin in bacteria for diabetes treatment

Question 10

What is the main advantage of 'next-generation' DNA sequencing over traditional Sanger sequencing?

Accepted Answer

It allows rapid and inexpensive sequencing of millions of DNA fragments simultaneously.

Question 11

The CRISPR-Cas9 system can be used to 'knock out' a gene in a cell. What is the primary purpose of this technique in research?

Accepted Answer

To determine the normal function of the gene by observing the effects of its absence.

Question 12

A forensic scientist analyzes a DNA sample using gel electrophoresis. The sample produces three bands at 500 bp, 1000 bp, and 2000 bp. What does this indicate about the DNA fragments?

Accepted Answer

The sample contains DNA fragments of three different lengths: 500, 1000, and 2000 base pairs.

Question 13

Which of the following best explains why Taq polymerase is used in PCR instead of a typical DNA polymerase from E. coli?

Accepted Answer

Taq polymerase is heat-stable and can withstand the high temperatures used during the denaturation step of PCR.

Question 14

A scientist wants to insert a gene for pest resistance into a plant. Which of the following steps is NOT required in this process?

Accepted Answer

Sequencing the entire plant genome before insertion

Question 15

Which of the following statements about gel electrophoresis is correct?

Accepted Answer

DNA fragments move toward the positive electrode because DNA is negatively charged.

Question 16

In a real-world scenario, which of the following would be a potential ethical concern related to genetic engineering?

Accepted Answer

The possibility of genetically modified organisms escaping into the environment and affecting local ecosystems.

Question 17

A patient has a genetic disorder caused by a single defective gene. Which genetic engineering technique could potentially be used to correct this mutation?

Accepted Answer

CRISPR-Cas9 gene editing

Question 18

Which of the following best describes the function of DNA ligase in the creation of recombinant DNA?

Accepted Answer

It forms covalent bonds between adjacent nucleotides, sealing the sugar-phosphate backbone of DNA fragments.

Question 19

A researcher is using next-generation sequencing to analyze a patient's genome. What is the main principle behind this technology?

Accepted Answer

Sequencing by synthesizing the complementary strand and electronically detecting each nucleotide added.

Question 20

Which of the following is a plausible risk associated with genetic engineering, as highlighted in the provided materials?

Accepted Answer

The risk of genetically engineered organisms breaking free and threatening the local population.

lecuture 24: Genetic Engineering: Tools, Techniques, and Applications

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