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
5. Genetics of Bacteria and Viruses
Working with Microorganisms
Problem 4aSanders - 3rd Edition
Textbook Question
Fifteen bacterial colonies growing on a complete medium are transferred to a minimal medium. Twelve of the colonies grow on minimal medium.
The serine biosynthetic pathway is a three-step pathway in which each step is catalyzed by the enzyme product of a different gene, identified as enzymes A, B, and C in the diagram below.
Mutant 1 grows only on In addition to growth on , mutant 2 also grows on and . Mutant 3 grows on and . Identify the step of the serine biosynthesis pathway at which each mutant is defective.
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Identify the compounds that each mutant can grow on, as these will help determine which step in the pathway is defective.
For Mutant 1, since it grows only on a specific compound, it indicates a defect in the first step catalyzed by Enzyme A, as it cannot convert 3-Phosphoglycerate to 3-Phospho-hydroxypyruvate.
For Mutant 2, since it grows on two compounds, it suggests a defect in the second step catalyzed by Enzyme B, as it cannot convert 3-Phospho-hydroxypyruvate to 3-Phosphoserine.
For Mutant 3, since it grows on two compounds, it indicates a defect in the third step catalyzed by Enzyme C, as it cannot convert 3-Phosphoserine to Serine.
Match each mutant to the corresponding enzyme defect based on the growth patterns on the specific compounds.
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Textbook Question
In this chapter, we have focused on genetic systems present in bacteria and on the viruses that use bacteria as hosts (bacteriophages). In particular, we discussed mechanisms by which bacteria and their phages undergo genetic recombination, which allows geneticists to map bacterial and bacteriophage chromosomes. In the process, we found many opportunities to consider how this information was acquired. From the explanations given in the chapter, what answers would you propose to the following questions?
How do we know that bacteria undergo genetic recombination, allowing the transfer of genes from one organism to another?
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