4a. The diagram below represents (a) the lac operon in the OFF state and (b) lac operon in the ON state. Assign labels to letters A-F based on known components in the pathway. lac operon A. Absence of lactose Regulator gene (lacI) Structural genes lacZ lacY lacA B. Transcription and translation No transcription C. D. E. Presence of lactose F. Transcription and translation Transcription and translation Enzymes β-Galactosidase Permease Transacetylase Glucose Galactose Lactose 4b. Briefly describe the changes in gene expression that happen in the lac operon when lactose is present in the cell. Include changes in the action of RNA polymerase and the lac repressor protein.
Added by Martin E.
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The only thing that is happening is that the lac repressor protein is keeping the expression of the structural genes low. B: When lactose is present, transcription and translation start up. The enzymes involved in these processes are the same as in the OFF state, Show more…
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Sri K.
Use the following diagram of the lac operon to answer the following questions. Any references to "proteins" in the questions are indicated by proteins A-D in the diagram. regulatory gene operon DNA PI lacI lacP lacO lacZ lacY lacA transcription transcription mRNA mRNA translation translation A B C D 1. Are the lacO and lacP regulatory genes, regulatory elements or structural genes? What are their functions? 2. The lacI gene encodes protein A in the diagram above. What is protein A called? What is the purpose of protein A? 3. The lac operon encodes 3 structural genes that are translated into 3 proteins (B, C and D). What are the 3 genes? What are the 3 proteins called? What are each of their functions/roles? a) b) c)
Use the following diagram of the lac operon to answer the following questions. Any references to "proteins" in the questions are indicated by proteins A-D in the diagram.
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