#Question id: 2860
#Unit 2. Cellular Organization
Lactose metabolism in E. coli is carried out by two enzymes, with possible involvement by a third. The genes for all three enzymes are clustered together and transcribed together from one promoter, yielding a polycistronic message. These three genes, linked in function, are therefore also linked in expression. They are turned off and on together.
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Negative control |
keeps the lac operon repressed in the absence of lactose. |
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positive control |
keeps the operon relatively inactive in the presence of glucose, even when lactose is present. |
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when all the glucose is gone and lactose is present, a mechanism should exist. |
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is mediated by a factor called catabolite activator protein (CAP), which, in conjunction with cyclic-AMP, stimulates transcription. |
#Question id: 10893
#Unit 10. Ecological Principles
The ___________ holds that two species with the same ecological requirements cannot coexist.
#Question id: 2028
#Unit 4. Cell Communication and Cell Signaling
Three distinct antigen X, Y and Z were use to raise antibody. Which one of them statements regarding antibody titers in serum is Incorrect?
#Question id: 2941
#Unit 2. Cellular Organization
Centromeric Rec8 becomes cleaved during:
#Question id: 15411
#Unit 8. Inheritance Biology