AP BIOLOGY

THE MOLECULAR BASIS OF INHERITANCE

DNA REPLICATION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
On the ‘lagging strand’ of DNA replication DNA is build in short segments (100-200 bases long) known as ____
A
RNA Primer
B
DNA Primer
C
Okazaki Segments
D
Kosak Sequence
Explanation: 

Detailed explanation-1: -Okazaki fragments are the short lengths of DNA that are produced by the discontinuous replication of the lagging strand. The range of length of these fragments in the bacterial cells is about 1000-2000 nucleotides, while that in eukaryotic cells is approximately 100-200 nucleotides in length.

Detailed explanation-2: -On the lagging strand, DNA synthesis restarts many times as the helix unwinds, resulting in many short fragments called “Okazaki fragments.” DNA ligase joins the Okazaki fragments together into a single DNA molecule.

Detailed explanation-3: -Due to the antiparallel orientation of the two chromosomal DNA strands, one strand (leading strand) is replicated in a mostly processive manner, while the other (lagging strand) is synthesized in short sections called Okazaki fragments.

Detailed explanation-4: -SIGNIFICANCE OF FRAGMENT SIZE Despite the much larger DNA content of eukaryotic compared with prokaryotic cells, Okazaki fragments are ∼1200 nt long in bacteria but only about 200 nt long in eukaryotes (Ogawa and Okazaki 1980).

Detailed explanation-5: -Okazaki fragments are short sequences of DNA nucleotides (approximately 150 to 200 base pairs long in eukaryotes) which are synthesized discontinuously and later linked together by the enzyme DNA ligase to create the lagging strand during DNA replication.

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