Origin of replication ($$\text{ori})$$

Incorporation of a dideoxynucleotide ($$\text{ddNTP})$$

Question 1

Which feature of a plasmid is essential for its replication in bacterial cells?

Accepted Answer

Origin of replication ($$	ext{ori})$$

Question 2

After transformation, how are bacterial cells containing recombinant plasmids typically selected?

Accepted Answer

By growing them on media containing a specific antibiotic

Question 3

Which enzyme is responsible for 'gluing' together DNA fragments with compatible ends during recombinant DNA creation?

Accepted Answer

DNA ligase

Question 4

What is the main difference between a genomic DNA library and a cDNA library?

Accepted Answer

Genomic libraries represent the entire genome, while cDNA libraries represent only the genes expressed as mRNA

Question 5

Which property of eukaryotic mRNA allows it to be purified from a mixture of nucleic acids?

Accepted Answer

Presence of a poly-A tail

Question 6

During PCR, what is the purpose of heating the reaction to 95°C?

Accepted Answer

To denature the DNA strands

Question 7

Which equation best describes the exponential amplification of DNA during PCR after $$n$$ cycles, starting with one template molecule?

Accepted Answer

$$2^n$$

Question 8

Gel electrophoresis separates DNA fragments primarily based on which property?

Accepted Answer

Size (length in base pairs)

Question 9

Which of the following best explains why restriction enzymes often recognize palindromic sequences?

Accepted Answer

Palindromic sequences allow for symmetrical cleavage of both DNA strands

Question 10

A researcher wants to express a human gene in bacteria. Why is a cDNA library preferred over a genomic DNA library for this purpose?

Accepted Answer

cDNA lacks introns, which bacteria cannot process

Question 11

Which step in the Sanger DNA sequencing method causes chain termination?

Accepted Answer

Incorporation of a dideoxynucleotide ($$	ext{ddNTP})$$

Question 12

What is the function of the PAM sequence in CRISPR/Cas9 genome editing?

Accepted Answer

It signals the Cas9 nuclease where to cleave the DNA

Question 13

Which of the following is a major ethical concern associated with genome editing technologies like CRISPR?

Accepted Answer

Potential for unintended genetic changes ('off-target' effects)

Question 14

A forensic scientist uses PCR to amplify DNA from a crime scene. Which limitation must they consider?

Accepted Answer

They must know the DNA sequence to design primers

Question 15

Which of the following best describes the principle of nucleic acid hybridization?

Accepted Answer

Complementary base-pairing between two single-stranded nucleic acids

Question 16

Why are plasmids considered ideal vectors for DNA cloning in bacteria?

Accepted Answer

They replicate independently and can carry selectable markers

Question 17

Which application of biotechnology is most directly related to environmental cleanup?

Accepted Answer

Genetically modified bacteria that degrade toxic waste

Question 18

In gel electrophoresis, why do DNA fragments move toward the positive pole (anode)?

Accepted Answer

Because DNA is negatively charged due to its phosphate backbone

Question 19

Which of the following is a direct outcome of the Human Genome Project?

Accepted Answer

Identification of ~20,000 protein-coding genes in humans

Question 20

A scientist wants to use CRISPR/Cas9 to correct a defective allele in a mouse model. What must be present at the target site for Cas9 to cleave?

Accepted Answer

A PAM sequence ($$5'	ext{NGG}3')$$

Biotechnology: Principles, Techniques, and Applications

Study Guide - Practice Questions