Textbook Question
There is a problem completing the replication of linear chromosomes at their ends. Describe the problem and identify why telomeres shorten in each replication cycle.
550
views
Ch. 7 - DNA Structure and Replication
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172
Not the one you use?Change textbookSelect a different textbook
Table of contents
- Ch. 1 - The Molecular Basis of Heredity, Variation, and Evolution64
- Ch. 2 - Transmission Genetics144
- Ch. 3 - Cell Division and Chromosome Heredity81
- Ch. 4 - Gene Interaction87
- Ch. 5 - Genetic Linkage and Mapping in Eukaryotes103
- Ch. 6 - Genetic Analysis and Mapping in Bacteria and Bacteriophages73
- Ch. 7 - DNA Structure and Replication71
- Ch. 8 - Molecular Biology of Transcription and RNA Processing79
- Ch. 9 - The Molecular Biology of Translation110
- Ch. 10 - Eukaryotic Chromosome Abnormalities and Molecular Organization100
- Ch. 11 - Gene Mutation, DNA Repair, and Homologous Recombination86
- Ch. 12 - Regulation of Gene Expression in Bacteria and Bacteriophage90
- Ch. 13 - Regulation of Gene Expression in Eukaryotes38
- Ch. 14 - Analysis of Gene Function via Forward Genetics and Reverse Genetics72
- Ch. 15 - Recombinant DNA Technology and Its Applications69
- Ch. 16 - Genomics: Genetics from a Whole-Genome Perspective49
- Ch. 17 - Organelle Inheritance and the Evolution of Organelle Genomes27
- Ch. 18 - Developmental Genetics43
- Ch. 19 - Genetic Analysis of Quantitative Traits66
- Ch. 20 - Population Genetics and Evolution at the Population, Species, and Molecular Levels105
Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172Not the one you use?Change textbook
Chapter 7, Problem 13
A sample of double-stranded DNA is found to contain 20% cytosine. Determine the percentage of the three other DNA nucleotides in the sample.
Verified step by step guidance1
Understand the base-pairing rules in DNA: Cytosine (C) pairs with Guanine (G), and Adenine (A) pairs with Thymine (T). This means the percentage of cytosine equals the percentage of guanine in the DNA sample.
Since the DNA is double-stranded, the total percentage of all four nucleotides (C, G, A, T) must add up to 100%.
Given that cytosine (C) makes up 20% of the DNA, guanine (G) must also make up 20% because of the base-pairing rule. Together, cytosine and guanine account for 40% of the DNA.
Subtract the combined percentage of cytosine and guanine (40%) from 100% to determine the combined percentage of adenine (A) and thymine (T).
Divide the remaining percentage equally between adenine (A) and thymine (T), as they pair with each other in equal amounts in double-stranded DNA.
Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
2mWas this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Base Pairing Rules
In DNA, the base pairing rules dictate that adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G). This means that the amount of adenine will equal the amount of thymine, and the amount of cytosine will equal the amount of guanine in a double-stranded DNA molecule. Understanding these rules is essential for calculating the percentages of the nucleotides based on the given information.
Recommended video:
Guided course
03:49
Base Distortions
Complementary Base Pairing
Complementary base pairing refers to the specific pairing of nitrogenous bases in DNA. Since the sample contains 20% cytosine, it must also contain 20% guanine due to their complementary relationship. This concept is crucial for determining the percentages of the other nucleotides in the DNA sample.
Recommended video:
Guided course
03:49Base Distortions
Percentage Composition of DNA
The percentage composition of DNA nucleotides can be calculated by knowing the total percentage must equal 100%. Given that cytosine and guanine each account for 20%, the remaining percentage (60%) must be divided equally between adenine and thymine, leading to each being 30%. This concept is fundamental for solving the problem presented.
Recommended video:
Guided course
01:45DNA Proofreading
Related Practice
Textbook Question
There is a problem completing the replication of linear chromosomes at their ends. What is the function of telomerase, and how does it operate to synthesize telomeres?
421
views
Textbook Question
Explain how RNA participates in DNA replication.
766
views
Textbook Question
Bacterial DNA polymerase I and DNA polymerase III perform different functions during DNA replication.
Identify the principal functions of each molecule.
604
views
Textbook Question
Bacterial DNA polymerase I and DNA polymerase III perform different functions during DNA replication.
If mutation inactivated DNA polymerase I in a strain of E. coli, would the cell be able to replicate its DNA? If so, what kind of abnormalities would you expect to find in the cell?
638
views
Textbook Question
Bacterial DNA polymerase I and DNA polymerase III perform different functions during DNA replication.
If a strain of E. coli acquired a mutation that inactivated DNA polymerase III function, would the cell be able to replicate its DNA? Why or why not?
915
views