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
13. Gene Regulation in Eukaryotes
GAL Regulation
Problem 22e
Textbook Question
Explain how the following mutations would affect transcription of the yeast GAL1 gene in the presence of galactose.
A deletion of the entire GAL3 gene.
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1
Understand the role of the GAL3 gene in yeast. GAL3 is involved in the activation of the GAL gene system, which includes GAL1, in the presence of galactose.
Recognize that GAL3 encodes a protein that helps in the conversion of galactose into a form that can activate the transcription of GAL genes.
Consider the effect of deleting the entire GAL3 gene. Without GAL3, the yeast cell cannot properly sense the presence of galactose, which is necessary for the activation of GAL1 transcription.
Analyze the impact on transcription. Without the GAL3 protein, the GAL gene system, including GAL1, would not be activated in the presence of galactose, leading to reduced or no transcription of GAL1.
Conclude that the deletion of GAL3 would result in the inability of yeast to metabolize galactose efficiently, as GAL1 transcription is crucial for this process.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
GAL1 Gene Function
The GAL1 gene in yeast encodes an enzyme involved in the metabolism of galactose. Its expression is tightly regulated by the presence of galactose, which acts as an inducer. Understanding the role of GAL1 is crucial for analyzing how mutations affect its transcription, particularly in response to galactose.
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GAL3 Gene Role
The GAL3 gene encodes a protein that plays a key role in the regulation of the GAL gene cluster, including GAL1. It acts as a sensor for galactose, facilitating the activation of transcription when galactose is present. A deletion of GAL3 would disrupt this regulatory mechanism, leading to altered transcription levels of GAL1.
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Transcription Regulation in Yeast
Transcription regulation in yeast involves various proteins and signaling pathways that respond to environmental cues, such as the availability of sugars. In the case of the GAL genes, the presence of galactose triggers a cascade that enhances transcription. Understanding this regulatory network is essential for predicting the effects of mutations on gene expression.
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