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

The Lac Operon

Microbiology

15. Central Dogma & Gene Regulation

The Lac Operon

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Multiple Choice

The lac operon is a(n) _ operon that is typically .

inducible; induced.

repressible; repressed.

inducible; repressed.

repressed; inducible.

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Understand the concept of an operon: An operon is a cluster of genes under the control of a single promoter and is transcribed into a single mRNA strand. It is a key feature in prokaryotic gene regulation.

Identify the type of operon: The lac operon is an example of an inducible operon. Inducible operons are usually off (repressed) but can be turned on (induced) in the presence of a specific substrate.

Recognize the typical state of the lac operon: In the absence of lactose, the lac operon is repressed because a repressor protein binds to the operator region, preventing transcription.

Determine the conditions for induction: When lactose is present, it acts as an inducer by binding to the repressor protein, causing a conformational change that releases the repressor from the operator, allowing transcription to proceed.

Conclude the correct description: The lac operon is typically repressed but can be induced in the presence of lactose, making it an inducible operon that is usually repressed.