Question 1

Which of the following best describes the main role of restriction enzymes (ER) in genetic engineering?

Accepted Answer

They recognize specific palindromic DNA sequences and cleave double-stranded DNA.

Question 2

During PCR, why is Taq polymerase specifically used instead of other DNA polymerases?

Accepted Answer

It is resistant to high temperatures required for DNA denaturation.

Question 3

Which of the following is a necessary component for in vitro DNA cloning using PCR?

Accepted Answer

Taq polymerase

Question 4

A scientist wants to clone a human gene into a bacterial cell. Which of the following steps is NOT required for this process?

Accepted Answer

Direct insertion of the gene into the bacterial chromosome without a vector

Question 5

Which property makes plasmids suitable as vectors in genetic engineering?

Accepted Answer

They replicate autonomously and can carry antibiotic resistance genes.

Question 6

What is the main advantage of using cDNA (ADNc) synthesized from mRNA for cloning human genes in bacteria?

Accepted Answer

cDNA lacks introns, making it suitable for expression in bacteria.

Question 7

Which of the following best describes the process of gel electrophoresis?

Accepted Answer

It separates DNA fragments based on their charge and size in an electric field.

Question 8

A PCR reaction is set up with the following thermal cycle: 95°C, 60°C, 72°C. What is the purpose of the 72°C step?

Accepted Answer

Extension of new DNA strands by Taq polymerase

Question 9

Which of the following is a palindromic DNA sequence recognized by the restriction enzyme EcoRI?

Accepted Answer

$$5'	ext{GAATTC}\ 3'$$

Question 10

If a DNA fragment is amplified by PCR for 30 cycles, starting from a single molecule, how many copies are theoretically produced?

Accepted Answer

$$2^{30}$$

Question 11

Which of the following is NOT a typical application of DNA cloning?

Accepted Answer

Synthesizing ATP in mitochondria

Question 12

What is the main function of primers in a PCR reaction?

Accepted Answer

They provide a starting point for DNA synthesis.

Question 13

Which of the following steps is unique to in vivo DNA cloning but not required in PCR?

Accepted Answer

Ligation of DNA fragments

Question 14

A researcher wants to identify a person based on their DNA. Which technique would be most appropriate?

Accepted Answer

Electrophoresis to compare DNA fragment patterns

Question 15

Which of the following is a direct medical application of nucleic acid analysis techniques?

Accepted Answer

Diagnosing genetic diseases prenatally

Question 16

Which of the following best explains why bacterial plasmids are used as vectors in genetic engineering?

Accepted Answer

They can carry foreign DNA and replicate autonomously in bacteria.

Question 17

Which enzyme is responsible for synthesizing cDNA from an mRNA template?

Accepted Answer

Reverse transcriptase

Question 18

What is the main reason for using antibiotic resistance genes in cloning vectors?

Accepted Answer

To select for cells that have taken up the vector

Question 19

Which of the following is a correct sequence of steps for obtaining recombinant DNA in vivo?

Accepted Answer

Isolate plasmid, cut with restriction enzyme, ligate gene, transform bacteria

Question 20

Which of the following statements about restriction sites (SR) is correct?

Accepted Answer

They are specific palindromic sequences recognized by restriction enzymes.

Genetic Engineering and DNA Cloning: Principles, Methods, and Applications

Study Guide - Practice Questions