Textbook Question
Kornberg showed that nucleotides are added to the 3' end of each growing DNA strand. In what way does an exposed 3'-OH group participate in strand elongation?
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Ch. 10 - DNA Replication
Klug10th EditionEssentials of GeneticsISBN: 9780135588789
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Table of contents
- Ch. 1 - Introduction to Genetics16
- Ch. 2 - Mitosis and Meiosis28
- Ch. 3 - Mendelian Genetics37
- Ch. 4 - Modification of Mendelian Ratios53
- Ch. 5 - Sex Determination and Sex Chromosomes32
- Ch. 6 - Chromosome Mutations: Variation in Number and Arrangement37
- Ch. 7 - Linkage and Chromosome Mapping in Eukaryotes36
- Ch. 8 - Genetic Analysis and Mapping in Bacteria and Bacteriophages24
- Ch. 9 - DNA Structure and Analysis38
- Ch. 10 - DNA Replication29
- Ch. 11 - Chromosome Structure and DNA Sequence Organization22
- Ch. 12 - The Genetic Code and Transcription36
- Ch. 13 - Translation and Proteins27
- Ch. 14 - Gene Mutation, DNA Repair, and Transposition34
- Ch. 15 - Regulation of Gene Expression in Bacteria22
- Ch. 16 - Regulation of Gene Expression in Eukaryotes37
- Ch. 17 - Recombinant DNA Technology27
- Ch. 18 - Genomics, Bioinformatics, and Proteomics30
- Ch. 19 - The Genetics of Cancer21
- Ch. 20 - Quantitative Genetics and Multifactorial Traits37
- Ch. 21 - Population and Evolutionary Genetics45
Chapter 10, Problem 7
What are the requirements for in vitro synthesis of DNA under the direction of DNA polymerase I?
Verified step by step guidance1
Understand that DNA polymerase I requires a template strand of DNA to guide the synthesis of the new DNA strand, so the first requirement is a single-stranded DNA template.
Recognize that DNA polymerase I cannot initiate DNA synthesis de novo; it needs a primer with a free 3'-OH group to add nucleotides, so a primer annealed to the template is necessary.
Provide the four deoxyribonucleotide triphosphates (dNTPs): dATP, dTTP, dGTP, and dCTP, which serve as the building blocks for the new DNA strand.
Include the DNA polymerase I enzyme itself, which catalyzes the polymerization reaction by adding nucleotides to the primer in the 5' to 3' direction.
Ensure the reaction mixture contains an appropriate buffer with Mg^{2+} ions, as these are essential cofactors for the enzymatic activity of DNA polymerase I.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Role of DNA Polymerase I
DNA Polymerase I is an enzyme that synthesizes DNA by adding nucleotides to a pre-existing strand. It requires a template strand to guide the sequence and can also remove RNA primers through its exonuclease activity, making it essential for DNA replication and repair.
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01:45
DNA Proofreading
Requirements for DNA Synthesis
In vitro DNA synthesis by DNA Polymerase I requires a single-stranded DNA template, a primer with a free 3'-OH group to initiate synthesis, all four deoxynucleotide triphosphates (dNTPs) as substrates, and appropriate buffer conditions including Mg2+ ions for enzyme activity.
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Primer-Template Structure
DNA Polymerase I cannot start DNA synthesis de novo; it needs a primer annealed to the template strand. The primer provides the free 3'-OH end necessary for the enzyme to add nucleotides, ensuring accurate and efficient DNA elongation.
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Related Practice
Textbook Question
How did Kornberg assess the fidelity of DNA polymerase I in copying a DNA template?
Textbook Question
Compare conservative, semiconservative, and dispersive modes of DNA replication.
Textbook Question
Which characteristics of DNA polymerase I raised doubts that its in vivo function is the synthesis of DNA leading to complete replication?
Textbook Question
Describe the role of ¹⁵N in the Meselson–Stahl experiment.
Textbook Question
Predict the results of the experiment by Taylor, Woods, and Hughes if replication were
(a) conservative and
(b) dispersive.
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