Biotechnology: Principles and Processes
Test 1

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Who among the following is credited with the discovery of restriction enzymes?

Stanley Cohen
Herbert Boyer
Hind II
Arber, Smith, and Nathans
4

Arber, Smith, and Nathans discovered restriction enzymes, which are essential tools in recombinant DNA technology.

Which of the following organisms is commonly used as a host in recombinant DNA technology?

Streptococcus
Escherichia coli
Aspergillus
Saccharomyces
2

Escherichia coli is a commonly used bacterial host in genetic engineering due to its fast growth and well-studied genetics.

Which enzyme is responsible for unwinding DNA strands during replication?

DNA polymerase
Ligase
Helicase
Endonuclease
3

Helicase unwinds the DNA double helix, allowing replication and transcription to occur.

What is the function of selectable markers in cloning vectors?

To help in DNA replication
To identify recombinant cells
To cut DNA at specific sites
To inhibit bacterial growth
2

Selectable markers, such as antibiotic resistance genes, help distinguish recombinant cells from non-recombinant ones.

Which of the following is NOT a tool of recombinant DNA technology?

Restriction enzymes
Ligases
Vectors
Ribosomes
4

Ribosomes are involved in protein synthesis, not in recombinant DNA technology. The main tools include restriction enzymes, ligases, and vectors.

Which type of bonds are broken when DNA is denatured at high temperatures?

Phosphodiester bonds
Peptide bonds
Hydrogen bonds
Glycosidic bonds
3

Hydrogen bonds between complementary base pairs are broken during DNA denaturation, allowing strand separation in processes like PCR.

Which of the following statements about plasmids is correct?

Plasmids are extra-chromosomal, circular DNA molecules.
Plasmids cannot replicate independently inside a host cell.
Plasmids are only found in eukaryotic cells.
Plasmids cannot be used as cloning vectors.
1

Plasmids are extra-chromosomal, circular DNA molecules that can replicate independently and are widely used as cloning vectors.

Which of the following statements about transformation in bacteria is incorrect?

Transformation allows bacteria to take up foreign DNA.
Transformation always requires a virus.
Some bacteria are naturally competent for transformation.
Transformation can be induced using calcium chloride treatment.
2

Transformation does not require a virus; it can occur naturally or be induced using chemical treatments.

Which of the following statements about restriction enzymes is correct?

Restriction enzymes cut DNA at specific recognition sites.
Restriction enzymes always produce blunt ends.
Restriction enzymes are not used in recombinant DNA technology.
Restriction enzymes randomly degrade DNA.
1

Restriction enzymes recognize specific palindromic sequences in DNA and cut precisely at those sites.

Which of the following statements about transformation is incorrect?

Transformation is the process of introducing foreign DNA into bacterial cells.
Transformation can be induced using calcium chloride treatment.
Transformation always requires a viral vector.
Some bacteria are naturally competent for transformation.
3

Transformation does not always require a viral vector; it can be done using chemical treatments or electroporation.

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