Question 1

Which step in the PCR process is responsible for separating the two strands of DNA, and at what temperature does this typically occur?

Accepted Answer

Denaturation; $$95^\circC$$

Question 2

A restriction enzyme cuts DNA at a specific sequence. If EcoRI recognizes the sequence $$5'	ext{GAATTC}\ 3'$$ and cuts between G and A, what type of ends are produced?

Accepted Answer

Sticky ends

Question 3

In recombinant DNA technology, what is the primary function of a plasmid?

Accepted Answer

To serve as a vector for gene transfer

Question 4

Which enzyme is used to join DNA fragments with sticky ends during cloning?

Accepted Answer

DNA ligase

Question 5

A patient’s blood sample is tested for dengue virus using RT-PCR. What is the role of reverse transcriptase in this process?

Accepted Answer

It converts viral RNA into complementary DNA (cDNA)

Question 6

Why is real-time PCR preferred for quantifying viral genomes in patient samples?

Accepted Answer

It allows for the measurement of DNA amplification as it happens using fluorescence

Question 7

Which of the following best describes a 'false negative' result in a COVID-19 PCR test?

Accepted Answer

The test fails to detect the virus even though it is present

Question 8

What is the purpose of using a selectable marker gene in a plasmid during recombinant DNA experiments?

Accepted Answer

To identify cells that have successfully taken up the plasmid

Question 9

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

Accepted Answer

Identifying which genes are expressed in cancer cells compared to healthy cells

Question 10

A subunit vaccine is designed using only specific parts of a pathogen. What is the main advantage of this approach?

Accepted Answer

It reduces the risk of adverse reactions by only using essential antigens

Question 11

In gene therapy, what is the role of a viral vector?

Accepted Answer

To deliver therapeutic genes into target cells

Question 12

Which equation best represents the exponential amplification of DNA during PCR?

Accepted Answer

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

Question 13

A scientist wants to clone a gene into a bacterial plasmid. Which sequence of steps is correct?

Accepted Answer

Cut plasmid and gene with restriction enzyme, ligate gene into plasmid, transform bacteria

Question 14

Why is it important for the CDC to confirm the strain of dengue virus in a patient sample?

Accepted Answer

To monitor outbreaks and track the spread of specific strains

Question 15

Which term describes the process of making complementary DNA (cDNA) from mRNA?

Accepted Answer

Reverse transcription

Question 16

What is the function of sticky ends in recombinant DNA technology?

Accepted Answer

They allow DNA fragments to easily join together

Question 17

Which of the following best describes the microbiome?

Accepted Answer

The community of microorganisms living in and on the human body

Question 18

A patient is suspected of having a genetic disorder. Which technique would be most appropriate for screening their DNA for disease-associated mutations?

Accepted Answer

Genetic screening

Question 19

Which of the following is NOT a typical use of PCR in molecular biology?

Accepted Answer

Synthesizing proteins from DNA

Question 20

If a scientist wants to study which genes are active in a cancer cell compared to a healthy cell, which technique should they use?

Accepted Answer

DNA microarray

Chpt 8 Study guide Microbiology Study Guide: Recombinant DNA Technology, PCR, and Related Concepts

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