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
12. Gene Regulation in Prokaryotes
Lac Operon
3:25 minutes
Problem 19a
Textbook Question
Textbook QuestionList possible genotypes for lac operon haploids that have the following phenotypic characteristics:
The operon genes are constitutively transcribed, and the strain grows on lactose medium. List two possible genotypes for this phenotype.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Lac Operon Structure
The lac operon is a set of genes in E. coli that are involved in the metabolism of lactose. It consists of three structural genes (lacZ, lacY, and lacA) and regulatory elements that control their expression. Understanding its structure is crucial for identifying how mutations can lead to constitutive expression, where the genes are continuously transcribed regardless of lactose presence.
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Lac Operon Overview
Constitutive Expression
Constitutive expression refers to the continuous transcription of genes regardless of environmental conditions. In the context of the lac operon, this can occur due to mutations in the regulatory genes (like lacI) that prevent the repressor from binding to the operator, leading to the constant production of enzymes necessary for lactose metabolism.
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Genotype and Phenotype Relationship
Genotype refers to the genetic makeup of an organism, while phenotype is the observable characteristics resulting from the genotype and environmental interactions. In this case, identifying genotypes that lead to a phenotype of constitutive expression on lactose medium requires understanding how specific mutations affect gene regulation and expression in the lac operon.
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