BIOLOGY 1A03 Study Guide - Midterm Guide: Lactose Permease, Lac Operon, Operon

• School: McMaster University
• Department: Biology
• Course: BIOLOGY 1A03
• Professor: Rosa Da Silva

Document Summary

Nutrient rich environment (amino acids, vitamins, nucleotides, carbs etc) Housekeeping genes: genes that are required all the time for normal functions. Includes genes for structural and ribosomal proteins and polymerases. Regulated genes: genes that are expressed when needed. Can be turned on when important enzymes or proteins are needed. Gene expression: when the functional product of the gene is made, modified, and activated- Transcription, translation, and protein modification must be completed, if any one of these steps is disrupted, the gene is not expressed. Transcriptional control: controls the amount of mrna that is produced in a cell (dna --> mrna) Cell can activate or inhibit transcription by controlling the binding of proteins (polymerases) to the promoter regions. Slowest, cell has to start from scratch, often prevalent with more drastic environmental changes (depleted glucose in e. coli) Most efficient/economical: cell does not waste energy making mrna or polypeptide unless it really needs to.