Enzymes in Nucleic Acid Degradation and Genetic Engineering

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Questions and Answers

What type of bond do nuclease enzymes break to degrade nucleic acids?

Glycosidic bond
Peptide bond
Phosphodiester bond (correct)
Hydrogen bond

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

Most commonly available restriction enzymes
Composed of only one subunit
Recognize and cleave DNA at the same site
Require AdoMet and ATP cofactors (correct)

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

To seal discontinuities in the sugar-phosphate backbone of DNA (correct)
To cut DNA at specific sequences
To add phosphate groups to DNA
To amplify DNA fragments

Which of the following enzymes is used to prevent the self-ligation of DNA molecules during cloning?

Alkaline phosphatase (D) Signup and view all the answers

What is the function of terminal transferase?

Adds nucleotides to any available 3' terminus (B) Signup and view all the answers

What is the key characteristic of DNase I?

It cuts either single-stranded or double-stranded DNA at essentially random sites. (C) Signup and view all the answers

What is the role of T4 DNA ligase?

To catalyze the formation of a phosphodiester bond between DNA fragments (B) Signup and view all the answers

What is a key difference between T4 DNA polymerase and DNA polymerase I?

T4 DNA polymerase lacks 5'-3' exonuclease activity, while DNA polymerase I has it. (B) Signup and view all the answers

What is the unique characteristic of Terminal Deoxynucleotidyl Transferase (TdT)?

It is template-independent and adds nucleotides to the 3'-OH of DNA. (C) Signup and view all the answers

Which of the following is the correct definition of a palindrome sequence recognized by restriction enzymes?

A sequence that reads the same forward and backward on complementary DNA strands (A) Signup and view all the answers

What type of ends are produced by restriction enzymes?

Blunt and sticky ends (C) Signup and view all the answers

Which of the following is true regarding blunt ends?

They can be joined to any other DNA fragment with blunt ends. (A) Signup and view all the answers

What is the 'star effect' in the context of restriction enzymes?

The ability of an enzyme to cleave sequences similar but not identical to its recognition sequence under extreme conditions (A) Signup and view all the answers

Which of the following is an example of how restriction enzymes are named?

After the bacterium from which they were isolated (D) Signup and view all the answers

What is the function of reverse transcriptase?

To synthesize DNA from an RNA template (C) Signup and view all the answers

Which of the following correctly describes the activity of Exonuclease III?

Acts as a 3' exonuclease that generates molecules with protruding 5’ termini (B) Signup and view all the answers

Which of the following DNA polymerases possesses a strong 3'-5' exonuclease activity, approximately 1000-fold greater than Klenow fragment?

T7 DNA Polymerase (A) Signup and view all the answers

In nick translation, which enzyme is used to replace some of the nucleotides of a DNA sequence with their labeled analogues?

DNA Polymerase I (C) Signup and view all the answers

Which statement accurately contrasts isoschizomers and neoschizomers?

Isoschizomers recognize the same sequence and cut at the same site; neoschizomers recognize the same sequence but cut differently. (A) Signup and view all the answers

What is the crucial role fulfilled by ribonucleases (RNases) in the preparation and analysis of recombinants?

To eliminate unwanted RNA from the preparation. (D) Signup and view all the answers

Which of the following best describes the function of the Klenow fragment of DNA polymerase I?

It has DNA polymerase and 3'→5' exonuclease activity but lacks 5'→3' exonuclease activity. (D) Signup and view all the answers

Which of the following factors affect the categorization of restriction enzymes into different types?

The position of their DNA cleavage site relative to the target sequence. (C) Signup and view all the answers

Which of the options below is NOT a characteristic of Type I restriction enzymes?

Subunits include two R(restriction) subunits and two M(methylation) subunits. (A) Signup and view all the answers

You are constructing a recombinant plasmid by inserting a gene of interest into a vector. After digestion with appropriate restriction enzymes, you want to prevent the vector from re-circularizing without incorporating the insert. Which enzyme would be most appropriate for this purpose?

Alkaline Phosphatase (C) Signup and view all the answers

The enzyme T4 RNA ligase is notable for catalyzing which specific reaction?

ATP-dependent formation of phosphodiester bonds between single-stranded RNA and DNA (D) Signup and view all the answers

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Flashcards

Enzymes in Recombinant DNA Tech

Enzymes used to cut, modify, and join DNA molecules.

Nucleases

Enzymes that degrade nucleic acids by breaking the phosphodiester bond.