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2 Cards in this Set
- Front
- Back
- 3rd side (hint)
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How do bacteria control metabolism?
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2 ways:
1) Adjust the activity of enzymes that are already present. 2) Adjust the production level of certain enzymes- regulate the expression of these genes. |
Using tryptophan, an essential amino acid, as an example:
1) The activity of the first enzyme in the tryptophan synthesis pathway is inhibited by the pathway's end product- tryptophan. 2) The cell stops making the enzymes needed to make tryptophan by stopping transcription of these genes- this occurs through the operon model. |
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Explain Operons
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Parts of the Operon:
1) Promoter: A region of the DNA molecule where RNA polymerase can bind to DNA and start transcription. 2) All the genes needed for making that certain protein are on one transcription unit. This means one single "on/off switch" is used- the genes are under coordinate control. The "switch" is called the operator. 3) Genes that are supposed to be transcribed. |
Important Words from there:
- operator- the region of DNA inside / between the promoter and enzyme coding regions - controls access of RNA polymerase to the genes |
