Table of contents
- 1. Introduction to Genetics51m
- 2. Mendel's Laws of Inheritance3h 37m
- 3. Extensions to Mendelian Inheritance2h 41m
- 4. Genetic Mapping and Linkage2h 28m
- 5. Genetics of Bacteria and Viruses1h 21m
- 6. Chromosomal Variation1h 48m
- 7. DNA and Chromosome Structure56m
- 8. DNA Replication1h 10m
- 9. Mitosis and Meiosis1h 34m
- 10. Transcription1h 0m
- 11. Translation58m
- 12. Gene Regulation in Prokaryotes1h 19m
- 13. Gene Regulation in Eukaryotes44m
- 14. Genetic Control of Development44m
- 15. Genomes and Genomics1h 50m
- 16. Transposable Elements47m
- 17. Mutation, Repair, and Recombination1h 6m
- 18. Molecular Genetic Tools19m
- 19. Cancer Genetics29m
- 20. Quantitative Genetics1h 26m
- 21. Population Genetics50m
- 22. Evolutionary Genetics29m
7. DNA and Chromosome Structure
DNA Structure
1:37 minutes
Problem 32b
Textbook Question
Textbook QuestionNewsdate: March 1, 2030. A unique creature has been discovered during exploration of outer space. Recently, its genetic material has been isolated and analyzed. This material is similar in some ways to DNA in its chemical makeup. It contains in abundance the 4-carbon sugar erythrose and a molar equivalent of phosphate groups. In addition, it contains six nitrogenous bases: adenine (A), guanine (G), thymine (T), cytosine (C), hypoxanthine (H), and xanthine (X). These bases exist in the following relative proportions: A =T = H and C = G = X X-ray diffraction studies have established a regularity in the molecule and a constant diameter of about 30 Å. Together, these data have suggested a model for the structure of this molecule. What base-pairing properties must exist for H and for X in the model?
Verified Solution
This video solution was recommended by our tutors as helpful for the problem above
Video duration:
1mPlay a video:
Was this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Base Pairing Rules
Base pairing rules dictate how nitrogenous bases in nucleic acids pair with one another. In DNA, adenine pairs with thymine (A-T) and cytosine pairs with guanine (C-G). The question introduces hypoxanthine (H) and xanthine (X), which necessitates understanding how these bases might pair with the existing bases, particularly in light of their specified proportions.
Recommended video:
Guided course
03:49
Base Distortions
Nucleotide Structure
Nucleotides, the building blocks of nucleic acids, consist of a sugar, a phosphate group, and a nitrogenous base. The presence of erythrose as the sugar and the unique nitrogenous bases in this extraterrestrial genetic material suggests a different structural framework compared to DNA. Understanding nucleotide structure is essential for predicting how these bases interact and form pairs.
Recommended video:
Guided course
06:25
DNA Structure
Molecular Structure and Stability
The stability and structure of nucleic acids are influenced by their molecular configuration, including the arrangement of sugar-phosphate backbones and base pairing. The mention of a consistent diameter of 30 Å and regularity in the molecule implies a helical structure similar to DNA. Analyzing how H and X fit into this model requires knowledge of how molecular structure affects base pairing and overall stability.
Recommended video:
Guided course
03:53
Ribosome Structure
Related Videos
Related Practice