DNA Replication and Enzymes

The video explains DNA replication, starting with the unwinding of the double helix by DNA helicase, forming a replication fork. RNA primers pair with DNA strands, and DNA polymerase adds nucleotides to synthesize new strands. The synthesis occurs in opposite directions due to the 5' to 3' directionality of DNA polymerase. Continuous synthesis occurs in the direction of the replication fork, while discontinuous synthesis happens in the opposite direction, requiring multiple priming events. DNA ligase joins the fragments, resulting in two complete daughter DNA molecules.

What is the primary function of DNA helicase during DNA replication?

• To replace RNA primers with DNA

• To unwind the double helix

• To join DNA fragments

• To synthesize new DNA strands

In the polymerase chain reaction, what type of primers are used?

• RNA primers

• Protein primers

• DNA primers

• Lipid primers

What is the role of DNA polymerase in DNA replication?

• To synthesize RNA primers

• To form the replication fork

• To add free nucleotides to the primers

• To unwind the DNA strands

Why are new DNA strands synthesized in opposite directions?

• Because DNA polymerase can synthesize in both directions

• Because the parent DNA strands are oriented in the same direction

• Because DNA polymerase can only synthesize in one direction

• Because the replication fork moves in a circular path

What is the difference between continuous and discontinuous DNA synthesis?

• Discontinuous synthesis occurs in the leading strand

• Continuous synthesis requires multiple priming events

• Continuous synthesis occurs in the lagging strand

• Discontinuous synthesis occurs in short fragments

What is required for the synthesis of each DNA fragment in the lagging strand?

• Continuous synthesis

• Multiple DNA polymerases

• A single priming event

• A separate priming event

What enzyme is responsible for joining separate DNA fragments?

• DNA helicase

• DNA polymerase

• RNA primase

• DNA ligase

What happens to RNA primers during the final steps of DNA replication?

• They are joined together by DNA ligase

• They are converted into DNA

• They are replaced with DNA

• They remain as part of the DNA strand

What is the result of DNA replication?

• Four single-stranded RNA molecules

• One double-stranded DNA molecule

• Two single-stranded DNA molecules

• Two complete double-stranded daughter DNA molecules

Which enzyme replaces RNA primers with DNA?

• RNA primase

• DNA ligase

• DNA polymerase

• DNA helicase