RNA Processing: Splicing and modifications allow mRNA to exit the nucleus.
Cytoplasm Regulation: mRNA degradation, translational control, and post-translational modifications.
Prokaryotic Gene Regulation
Simpler than eukaryotic; primarily involves operons.
Operon Structure:
Regulatory Gene: Produces repressor protein.
Promoter: RNA polymerase binding site.
Operator: Repressor binding site.
Structural Genes: Transcribed into proteins.
Terminator: Signals end of a gene.
Types of Operons
Inducible Operons: Expression induced by removing the repressor.
Example: Lac Operon (Lactose metabolism).
Inducer (e.g., allolactose) inactivates the repressor.
Repressible Operons: Gene expression normally on, can be repressed.
Example: Trp Operon (Tryptophan synthesis).
Co-repressor (tryptophan) activates the repressor.
Genetic Change in Bacteria
Importance for microbiology and biotechnology.
Methods of genetic change:
Mutation: Changes DNA sequence.
Transformation: Uptake of naked DNA from the environment.
Conjugation: Transfer of plasmids via pili.
Transduction: Gene transfer by phages.
Mutation Types and Effects
Base Substitution: Single base change, can be silent, missense, or nonsense mutations.
Frameshift Mutation: Insertion or deletion changes reading frame, can lead to extensive missense or nonsense.
Mutations: Can be caused by chemicals, radiation, or replication errors.
Practice Problems
Examples of how specific mutations affect protein synthesis and potential effects on bacterial survival and function.
Significance
Genetic changes are crucial for bacterial adaptation, including antibiotic resistance.
Understanding mechanisms aids in tackling antibiotic resistance in medicine.
Conclusion
Gene expression and the mechanisms of genetic change are central to understanding microbial genetics and their applications in biotechnology and medicine.
Further exploration in future chapters on biotechnology and antibiotics.