Table of contents

1. Introduction to Microbiology3h 22m
2. Disproving Spontaneous Generation1h 18m
3. Chemical Principles of Microbiology3h 38m
4. Water1h 28m
5. Molecules of Microbiology2h 23m
6. Cell Membrane & Transport3h 28m
7. Prokaryotic Cell Structures & Functions5h 52m
8. Eukaryotic Cell Structures & Functions2h 18m
9. Microscopes2h 46m
10. Dynamics of Microbial Growth4h 36m
11. Controlling Microbial Growth4h 10m
12. Microbial Metabolism5h 16m
13. Photosynthesis2h 31m
14. DNA Replication2h 25m
15. Central Dogma & Gene Regulation7h 14m
16. Microbial Genetics4h 44m
17. Biotechnology3h 0m
18. Viruses, Viroids, & Prions4h 56m
19. Innate Immunity7h 15m
20. Adaptive Immunity7h 14m
21. Principles of Disease6h 57m

15. Central Dogma & Gene Regulation

Glucose's Impact on Lac Operon

Microbiology

15. Central Dogma & Gene Regulation

Glucose's Impact on Lac Operon

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Multiple Choice

How does extracellular glucose inhibit transcription of the lac operon?

By strengthening the binding of the repressor to the operator.

By weakening the binding of the repressor to the operator.

By inhibiting RNA polymerase from opening the strands of DNA to initiate transcription.

By reducing the levels of intracellular cAMP.

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Verified step by step guidance

Understand the role of the lac operon: The lac operon is a set of genes responsible for the metabolism of lactose in bacteria. It is regulated by the presence or absence of lactose and glucose.

Learn about the role of cAMP: Cyclic AMP (cAMP) is a molecule that helps activate the lac operon by binding to the catabolite activator protein (CAP), which then facilitates the binding of RNA polymerase to the promoter region of the lac operon.

Explore the effect of glucose on cAMP levels: When extracellular glucose is present, it leads to a decrease in intracellular cAMP levels. This is because glucose inhibits the enzyme adenylate cyclase, which is responsible for converting ATP to cAMP.

Connect cAMP levels to lac operon transcription: Lower levels of cAMP mean that CAP cannot bind effectively to the promoter region, reducing the ability of RNA polymerase to initiate transcription of the lac operon.

Conclude the mechanism: Therefore, extracellular glucose inhibits transcription of the lac operon by reducing the levels of intracellular cAMP, which in turn prevents the activation of the lac operon by CAP.