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Molecular Basis of Inheritance — BIOLOGY STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceBIOLOGYMolecular Basis of Inheritance5 Marks
Question
Explain the difference between the forward strand and lagging strand of DNA.
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Answer

Differences between the Leading Strand and Lagging Strand :
Leading StrandLagging Strand
1. It is a replicated strand of DNA which grows continuously without any gap.1. Lagging strand is a replicated strand of DNA which is formed in short segments called Okazaki, fragments. Its growth is discontinuous.
2. It does not require DNA ligase for its growth.2. DNA-ligase is required for joining Okazaki fragments.
3. The direction of growth of the leading strand is $5^{\prime} \rightarrow 3^{\prime}$.3. The direction of growth of the lagging strand is $3^{\prime} \rightarrow 5^{\prime}$ though in each Okazaki fragment it is $5^{\prime} \rightarrow 3^{\prime}$.
4. Only a single RNA primer is required.4. Starting of each Okazaki fragment requires a new RNA primer.
5. Formation of leading strand is quite rapid.5. Formation of lagging strand is slower.
6. Its template opens in $3^{\prime} \rightarrow 5^{\prime}$ direction.6. Its template opens in $5^{\prime} \rightarrow 3^{\prime}$ direction.
7. Formation of leading strand begins immediately at the beginning of replication.7. Formation of lagging strand begins a bit later than that of leading strand.

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