1. What is the primary function of DNA ligase in recombinant DNA technology?
A.
To join DNA fragments together
B.
To separate the two DNA strands
C.
To cut DNA at specific sequences
D.
To make RNA from DNA
Correct Answer:
To join DNA fragments together
Explanation:
DNA ligase joins DNA fragments by forming bonds between adjacent nucleotides.
2. Which type of bond is formed by DNA ligase between DNA fragments?
A.
Hydrogen bond
B.
Peptide bond
C.
Phosphodiester bond
D.
Glycosidic bond
Correct Answer:
Phosphodiester bond
Explanation:
DNA ligase seals the sugar-phosphate backbone by forming phosphodiester bonds between DNA nucleotides.
3. DNA ligase is commonly used to join a foreign DNA fragment with which molecule?
A.
A vector DNA molecule
B.
A protein molecule
C.
A lipid molecule
D.
A carbohydrate molecule
Correct Answer:
A vector DNA molecule
Explanation:
DNA ligase joins the foreign DNA fragment to vector DNA to form recombinant DNA.
4. Which enzyme is widely used for joining DNA fragments in genetic engineering?
A.
DNA ligase
B.
Amylase
C.
Lipase
D.
Pepsin
Correct Answer:
DNA ligase
Explanation:
DNA ligase is the enzyme specifically used to seal breaks and join DNA fragments during recombinant DNA formation.
5. What does DNA ligase do after complementary sticky ends of DNA fragments pair?
A.
It cuts the paired DNA ends
B.
It seals the sugar-phosphate backbone
C.
It converts DNA into RNA
D.
It removes all nucleotides
Correct Answer:
It seals the sugar-phosphate backbone
Explanation:
After sticky ends pair through complementary bases, DNA ligase seals the backbone by forming phosphodiester bonds.
6. The product formed when DNA ligase joins a foreign DNA fragment to a vector is called:
A.
Recombinant DNA
B.
Messenger RNA
C.
Amino acid
D.
A restriction enzyme
Correct Answer:
Recombinant DNA
Explanation:
DNA ligase joins DNA from different sources, producing a recombinant DNA molecule.
7. Which enzyme helps prevent breaks in the DNA backbone during DNA joining?
A.
DNA ligase
B.
Restriction endonuclease
C.
RNA polymerase
D.
Helicase
Correct Answer:
DNA ligase
Explanation:
DNA ligase repairs breaks in the DNA sugar-phosphate backbone by joining adjacent DNA ends.
8. DNA ligase is most directly involved in which step of recombinant DNA formation?
A.
Ligation
B.
Transcription
C.
Translation
D.
DNA denaturation
Correct Answer:
Ligation
Explanation:
Ligation is the process in which DNA ligase joins compatible DNA fragments.
9. Which commonly used enzyme is obtained from bacteriophage T4 and can join DNA fragments?
A.
T4 DNA ligase
B.
T4 amylase
C.
T4 protease
D.
T4 lipase
Correct Answer:
T4 DNA ligase
Explanation:
T4 DNA ligase is a commonly used ligase that joins DNA fragments by sealing phosphodiester bonds.
10. What is the result of DNA ligase action on two compatible DNA fragments?
A.
A continuous DNA molecule is formed
B.
The DNA fragments are changed into proteins
C.
The DNA fragments are completely degraded
D.
The DNA fragments become RNA molecules
Correct Answer:
A continuous DNA molecule is formed
Explanation:
DNA ligase connects compatible DNA ends and produces a continuous DNA molecule.
Short questions are currently unavailable for this page.