DNA Structure and Replication

Front

What are Okazaki fragments?

Back

Short sequences of DNA nucleotides synthesized on the lagging strand during DNA replication, which are later joined together by DNA ligase.

Front

What enzyme adds nucleotides to the newly synthesized strand of DNA?

Back

DNA polymerase III.

Front

What is the role of a replication fork in DNA replication?

Back

It is the Y-shaped region where the DNA double helix is unwound, allowing for the synthesis of new strands.

Front

What enzyme releases supercoiling in DNA?

Back

Topoisomerase I, which cuts one strand of DNA to allow it to rotate freely.

Front

How many origins of replication are typically present in a eukaryotic DNA molecule?

Back

Multiple origins of replication, often represented as several points along the DNA strand.

Front

What is the function of primase in DNA replication?

Back

Primase synthesizes a short RNA primer that provides a starting point for DNA polymerase to begin synthesis.

Front

What is the difference between the leading strand and the lagging strand during DNA replication?

Back

The leading strand is synthesized continuously toward the replication fork, while the lagging strand is synthesized in short segments away from the fork.

Front

What is the role of DNA ligase in DNA replication?

Back

DNA ligase joins Okazaki fragments on the lagging strand by forming phosphodiester bonds between them.

Front

What is the significance of the 5' to 3' direction in DNA synthesis?

Back

DNA polymerases can only add nucleotides to the 3' end of a growing DNA strand, thus DNA synthesis occurs in the 5' to 3' direction.

Front

What is the function of helicase in DNA replication?

Back

Helicase unwinds the DNA double helix, separating the two strands to allow replication to occur.