Question 1

Which of the following best describes recombinant DNA?

Accepted Answer

DNA from two different sources combined into a single molecule.

Question 2

What is the primary function of restriction enzymes in DNA technology?

Accepted Answer

To cleave DNA at specific sequences known as restriction sites.

Question 3

Which enzyme is responsible for joining the sticky ends of DNA fragments during the creation of recombinant DNA?

Accepted Answer

DNA ligase

Question 4

In the process of DNA cloning, what is the correct order of steps for splicing foreign DNA into a plasmid and inserting it into a bacterium?

Accepted Answer

Extract plasmid DNA; Cut with restriction enzymes; Hydrogen-bond to non-plasmid DNA; Use ligase to seal; Transform bacteria.

Question 5

A researcher wants to amplify a specific DNA sequence rapidly in a test tube. Which technique should they use?

Accepted Answer

Polymerase Chain Reaction (PCR)

Question 6

Which of the following is NOT required for a standard PCR reaction?

Accepted Answer

DNA ligase

Question 7

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

Accepted Answer

It is not affected by high temperatures used during denaturation.

Question 8

If you start with one double-stranded DNA molecule and perform 6 cycles of PCR, how many double-stranded DNA molecules will you have at the end?

Accepted Answer

$$2^6 = 64$

Question 9

During gel electrophoresis, DNA fragments migrate towards the positive electrode because:

Accepted Answer

DNA is negatively charged and attracted to the positive anode.

Question 10

Which of the following best explains why smaller DNA fragments move further in an agarose gel during electrophoresis?

Accepted Answer

Smaller fragments encounter less resistance moving through the gel matrix.

Question 11

A Southern blot is used to:

Accepted Answer

Detect specific DNA sequences using a labeled probe.

Question 12

Which of the following is a key feature of short tandem repeats (STRs) that makes them useful for DNA fingerprinting?

Accepted Answer

The number of repeats varies greatly among individuals.

Question 13

Which of the following is NOT required for a dideoxy (Sanger) sequencing reaction?

Accepted Answer

RNA polymerase

Question 14

Dideoxynucleotides (ddNTPs) terminate DNA synthesis because:

Accepted Answer

They lack a free 3' OH group required for phosphodiester bond formation.

Question 15

A geneticist uses a radioactive probe in a Southern blot to detect Gene X in a patient's DNA. How will the geneticist know if the patient possesses Gene X?

Accepted Answer

The probe will bind to the membrane if Gene X is present.

Question 16

Which of the following best describes the process of transformation in recombinant DNA technology?

Accepted Answer

The process by which a cell takes up foreign DNA from its environment.

Question 17

Which of the following is the correct sequence of steps in one cycle of the polymerase chain reaction (PCR)?

Accepted Answer

Denature DNA; Anneal primers; Extend primers utilizing a thermostable DNA polymerase.

Question 18

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

Accepted Answer

Producing human insulin in transgenic E. coli for diabetic patients.

Question 19

What is the main purpose of using a DNA probe in molecular biology experiments?

Accepted Answer

To detect the presence of a specific DNA sequence by hybridization.

Question 20

Which of the following statements about DNA fingerprinting is correct?

Accepted Answer

It is used to determine if two DNA samples are from the same individual.

Recombinant DNA Technology and DNA-Based Techniques in Microbiology

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