Restriction Enzymes: The Molecular Scissors of Genetic Engineering

Question 1

In genetic engineering, restriction enzymes are molecular tools that perform a specific function. Which of the following choices accurately describes their role?

Accepted Answer

Restriction enzymes recognize and cut DNA at specific sequences, creating sticky ends.

Answer

Restriction enzymes randomly cut DNA at different locations.

Answer

Restriction enzymes are produced by viruses to integrate their genetic material into host cells.

Question 2

Identify the restriction enzyme classified as Type III:

Accepted Answer

EcoP15I

Answer

EcoRI

Answer

HindII

Question 3

Which of the following is NOT a characteristic of restriction enzymes?

Accepted Answer

They are insensitive to methylation

Answer

They recognize double-stranded DNA sequences

Answer

They cut DNA strands at staggered sites

Answer

They have a high degree of specificity

Question 4

Which of the following is not a recognized type of restriction enzyme?

Accepted Answer

Type IV

Answer

Type I

Answer

Type II

Answer

Type III

Question 5

Which of these is NOT a recognized type of restriction enzyme?

Accepted Answer

Type IV

Answer

Type I

Answer

Type II

Question 6

Which of the following is a characteristic of restriction enzymes?

Accepted Answer

They recognize and cut DNA at specific nucleotide sequences.

Answer

They cut DNA at any random nucleotide sequence.

Answer

They only cut DNA from eukaryotic organisms.

Answer

They are used to repair damaged DNA.

Question 7

The recognition sequence for EcoRI is:

Accepted Answer

5'-GAATTC-3'

Answer

5'-GCATGC-3'

Answer

5'-ATCGAT-3'

Answer

5'-CTTAAG-3'

Question 8

Which enzyme is used to join DNA fragments together?

Accepted Answer

DNA ligase

Answer

Restriction enzyme

Answer

Helicase

Answer

Polymerase

Question 9

Restriction enzymes are essential tools in genetic engineering for:

Accepted Answer

Cutting DNA at specific sequences to isolate and recombine genes for further analysis or manipulation.

Answer

Sequencing DNA.

Answer

Amplifying DNA sequences by PCR.

Question 10

Which of the following is a potential application of restriction enzymes in medicine?

Accepted Answer

Genetic testing and diagnosis

Answer

Developing biofuels

Answer

Creating genetically modified crops

Answer

Producing laundry detergents

Question 11

Restriction enzymes are primarily found in:

Accepted Answer

Bacteria

Answer

Fungi

Answer

Plants

Answer

Viruses

Question 12

Which of the following factors can affect the activity and efficiency of restriction enzymes?

Accepted Answer

Temperature, pH, and salt concentration

Answer

Light intensity

Answer

Magnetic field

Answer

Gravity

Question 13

Restriction enzymes play a crucial role in the process of:

Accepted Answer

Restriction fragment length polymorphism (RFLP) analysis

Answer

Polymerase chain reaction (PCR)

Answer

Electrophoresis

Question 14

Which of the following is NOT a characteristic of restriction enzymes?

Accepted Answer

They cleave DNA at random sequences

Answer

They are highly specific for their recognition sequence

Answer

They produce sticky ends in the DNA

Answer

They are useful in genetic mapping

Question 15

What is the recognition sequence for the restriction enzyme EcoRI?

Accepted Answer

GAATTC

Answer

CCCGGG

Answer

CTTAAG

Answer

GGATCC

Question 16

Which of the following is an application of restriction enzymes in genetic engineering?

Accepted Answer

Inserting foreign genes into plasmids

Answer

Identifying mutations

Answer

Sequencing DNA only

Answer

Amplifying DNA fragments only

Question 17

What is the difference between sticky ends and blunt ends produced by restriction enzymes?

Accepted Answer

Sticky ends have complementary overhangs, while blunt ends do not

Answer

Sticky ends are used for ligation, while blunt ends are used for restriction digestion

Answer

Sticky ends are produced by Type I enzymes, while blunt ends are produced by Type II enzymes

Question 18

How can restriction enzymes be used to create a genetic map of an organism?

Accepted Answer

By cutting DNA at multiple sites and analyzing the fragment sizes

Answer

By comparing the DNA of different individuals

Answer

By sequencing the entire genome, which is too costly

Question 19

Which of the following is an advantage of using restriction enzymes in genetic engineering?

Accepted Answer

They can be used to cut DNA at specific sequences

Answer

They are inexpensive, which is not true

Answer

They are highly efficient, which is true but not unique

Answer

They are easy to use, which is not unique

Question 20

How can restriction enzymes be used to create transgenic organisms?

Accepted Answer

By transferring genes from one organism to another

Answer

By mutating genes, which is not done with restriction enzymes

Answer

By sequencing genes, which is not done with restriction enzymes

Answer

By amplifying genes, which is not done with restriction enzymes

Question 21

Which of the following is the recognition sequence for EcoRI?

Accepted Answer

GAATTC

Answer

CTCGAG

Answer

GGATCC

Answer

ATCGAT

Question 22

What is the primary function of a sticky end produced by restriction enzymes?

Accepted Answer

To facilitate the ligation of complementary DNA fragments

Answer

To prevent DNA degradation

Answer

To mark the location of specific genes

Question 23

Which enzyme is responsible for adding methyl groups to DNA to protect it from restriction enzyme digestion?

Accepted Answer

DNA methylase

Answer

Helicase

Answer

Polymerase

Answer

Ligase

Question 24

Which technique utilizes restriction enzymes to generate a population of DNA fragments of varying sizes?

Accepted Answer

Partial digestion

Answer

PCR

Answer

Gel electrophoresis

Answer

Southern blotting

Question 25

What is a major limitation of using restriction enzymes in genetic engineering?

Accepted Answer

Restriction enzymes can only cut DNA at specific, predetermined sequences

Answer

Restriction enzymes are expensive

Answer

Restriction enzymes are difficult to use

Answer

Restriction enzymes may introduce mutations

Question 26

Which enzyme is primarily responsible for ligating DNA fragments together?

Accepted Answer

Ligase

Answer

Polymerase

Answer

Topoisomerase

Answer

Helicase

Question 27

Which of the following is **not** an advantage of using restriction enzymes in genetic engineering?

Accepted Answer

Restriction enzymes can be used to insert genes into random locations within the genome

Answer

Restriction enzymes are highly specific

Answer

Restriction enzymes produce predictable results

Question 28

Which of the following is NOT a characteristic of restriction enzymes?

Accepted Answer

They cut DNA at random locations.

Answer

They produce complementary ends.

Answer

They are used in genetic engineering.

Answer

They recognize specific DNA sequences.

Question 29

Which of the following is an example of a type II restriction enzyme?

Accepted Answer

EcoRI

Answer

RNase H

Answer

Telomerase

Answer

Primase

Question 30

Which biochemical process is used by restriction enzymes to cut DNA?

Accepted Answer

Hydrolysis

Answer

Phosphorylation

Answer

Oxidation

Answer

Methylation

Question 31

What is the primary function of DNA ligase in genetic engineering?

Accepted Answer

Joining DNA fragments together

Answer

Transcribing DNA into RNA

Answer

Cutting DNA at specific sequences

Answer

Translating RNA into protein

Question 32

Which of the following factors can influence the activity of restriction enzymes?

Accepted Answer

Temperature, pH, and metal ions

Answer

Light intensity

Answer

Humidity

Answer

Pressure

Question 33

How do exonucleases differ from endonucleases?

Accepted Answer

Exonucleases remove nucleotides from the ends of DNA, while endonucleases cut DNA within the molecule.

Answer

Exonucleases cut DNA, while endonucleases add nucleotides to DNA.

Question 34

How can restriction enzymes be utilized to analyze DNA?

Accepted Answer

By cutting DNA into fragments that can be separated and visualized on a gel.

Answer

By sequencing DNA directly.

Answer

By amplifying DNA.

Question 35

What is the main function of restriction enzymes?

Accepted Answer

To cut DNA at specific sequences

Answer

To copy DNA into RNA

Answer

To join pieces of DNA together

Answer

To make many copies of a DNA sequence

Question 36

What is the 'recognition sequence' of a restriction enzyme?

Accepted Answer

A specific pattern of DNA bases that the enzyme recognizes

Answer

The 3D shape of the enzyme molecule

Answer

A specific pattern of amino acids in the enzyme

Answer

Any random sequence of DNA bases

Question 37

A restriction enzyme that creates 'sticky ends' will:

Accepted Answer

Cut DNA in a way that leaves single-stranded overhangs

Answer

Cut DNA at any random point along the molecule

Answer

Stop other enzymes from joining DNA fragments

Answer

Cut DNA to create blunt ends with no overhangs

Question 38

Which of these is NOT a typical use for restriction enzymes?

Accepted Answer

Making many copies of a specific DNA region (PCR)

Answer

Mapping the location of genes on chromosomes

Answer

Combining DNA from different sources (recombinant DNA)

Question 39

Where are restriction enzymes usually found in nature?

Accepted Answer

Bacteria and archaea

Answer

Plant cells

Answer

Animal cells

Answer

Viruses

Question 40

What is the main role of restriction enzymes in their natural host organisms?

Accepted Answer

To defend against foreign DNA, like viruses

Answer

To control which genes are turned on or off

Answer

To break down waste products inside cells

Answer

To copy the organism's own DNA

Question 41

What type of chemical bond do restriction enzymes break in DNA?

Accepted Answer

Phosphodiester bond

Answer

Peptide bond

Answer

Hydrogen bond

Answer

Glycosidic bond

Question 42

Why are restriction enzymes important for genetic engineering?

Accepted Answer

They let us cut and paste DNA pieces precisely

Answer

They separate DNA pieces based on their size

Answer

They make many copies of a specific DNA region

Question 43

A scientist wants to put a gene into a plasmid. Both the gene and the plasmid have recognition sites for the restriction enzyme BamHI. Why is BamHI a good choice for this experiment?

Accepted Answer

It creates matching sticky ends on both the gene and the plasmid, which can then be joined together

Answer

BamHI cuts DNA randomly, increasing the chances of the gene going into the plasmid

Answer

BamHI is the only restriction enzyme available for this task