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Mitochondrial DNA (mtDNA) replicates differently from nuclear DNA. Scientists believe replication of the second mtDNA strand begins after two-thirds of the first strand has been replicated. A piece of mtDNA contains 33,140 nucleotides and it takes 0.02 seconds to replicate a nucleotide. It would take seconds to copy this mtDNA to the nearest whole.

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Important Questions on Nucleic Acids and Protein Synthesis

EASY
Biology>Genetics and Evolution P1>Nucleic Acids and Protein Synthesis>DNA Replication
Matthew Meselson and Franklin Stahl grew E.coli (doubling time is 20 min ) in medium containing NH415Cl for many generations. Then the E. coli was transferred to medium containing NH414Cl. After 40 minutes, the cells were harvested and DNA was extracted and subjected to caesium chloride density gradient centrifugation. The proportion of light and hybrid DNA densities will be:
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Biology>Genetics and Evolution P1>Nucleic Acids and Protein Synthesis>DNA Replication
E. coli fully labelled with N15 is allowed to grow in N14 medium. The two strands of DNA molecule of the first generation bacteria have:
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Biology>Genetics and Evolution P1>Nucleic Acids and Protein Synthesis>DNA Replication
An E. coli whose DNA is fully labeled by 15N is grown in a medium containing 14NH4Cl. What will be the percentage of hybrid 15N/14N and light14N/14N DNA  molecules at the end of 80 minutes (assume that doubling time of E. coli is 20 minutes)?
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Biology>Genetics and Evolution P1>Nucleic Acids and Protein Synthesis>DNA Replication

What is the significance of Meselson and Stahl's experiment?

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Biology>Genetics and Evolution P1>Nucleic Acids and Protein Synthesis>DNA Replication
E. coli has only 4.6×106 base pairs and completes the process of replication within 18 minutes; then the average rate of polymerisation is approximately:
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Biology>Genetics and Evolution P1>Nucleic Acids and Protein Synthesis>DNA Replication
Meselson and Stahl carried out centrifugation in CsCl2 density gradient to separate:
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Biology>Genetics and Evolution P1>Nucleic Acids and Protein Synthesis>DNA Replication
Arrange the following events of the replication of DNA. Choose the correct alternative?
(i) Bonds between complementary bases breaks.
(ii) Bonds between complementary bases forms.
(iii) DNA molecules are uncoiled.
(iv) Opposite strands separate.
(v) Sugar phosphate bonds form.
(vi) Free nucleotides align with the complementary nucleotides on each strand.
MEDIUM
Biology>Genetics and Evolution P1>Nucleic Acids and Protein Synthesis>DNA Replication
What are Okazaki fragments?
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Biology>Genetics and Evolution P1>Nucleic Acids and Protein Synthesis>DNA Replication
Light DNA N14 transferred to N15 labelled culture medium for replication. The ratio of total number of N15 and N14 labelled strands of DNA extracted from the culture after three generations
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Biology>Genetics and Evolution P1>Nucleic Acids and Protein Synthesis>DNA Replication
Which one of the following elements is not directly involved in transcription?
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Biology>Genetics and Evolution P1>Nucleic Acids and Protein Synthesis>DNA Replication

Give an account of Meselson and Stahl's experiment.

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Biology>Genetics and Evolution P1>Nucleic Acids and Protein Synthesis>DNA Replication
During DNA replication, Okazaki fragments are used to elongate:
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Biology>Genetics and Evolution P1>Nucleic Acids and Protein Synthesis>DNA Replication
Describe the semiconservative method of DNA replication with diagram.
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Biology>Genetics and Evolution P1>Nucleic Acids and Protein Synthesis>DNA Replication
"Use of heavy isotope of nitrogen by Meselson and Stahl demonstrated semi-conservative mode of replication of a DNA molecule." Explain how did they arrive at this conclusion.
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Biology>Genetics and Evolution P1>Nucleic Acids and Protein Synthesis>DNA Replication
Diagrammatically express the Watson Crick's semiconservative models of DNA replication.
MEDIUM
Biology>Genetics and Evolution P1>Nucleic Acids and Protein Synthesis>DNA Replication
Draw a labelled diagram of replicating fork in DNA helix.
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Biology>Genetics and Evolution P1>Nucleic Acids and Protein Synthesis>DNA Replication
What is the function of DNA ligase?
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Biology>Genetics and Evolution P1>Nucleic Acids and Protein Synthesis>DNA Replication
Which one of the following will be the ratio of heavy, intermediate and light bands in Meselson and Stahl's experiment after two generations if DNA replication were conservative?
MEDIUM
Biology>Genetics and Evolution P1>Nucleic Acids and Protein Synthesis>DNA Replication
Choose the correct pair from the following.
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Biology>Genetics and Evolution P1>Nucleic Acids and Protein Synthesis>DNA Replication
A mixture of equal numbers of fast and slow dividing cells is cultured in medium containing a trace amount of radioactively labeled thymidine for one hour. The cells are then transferred to regular (unlabeled) medium. After 24hrs of growth in regular media