Microbial Control and Genetics Exam Review

Chapter 9: Controlling Microbial Growth

• Key Concepts: Types of chemical methods, processes to control microbial growth using physical or chemical means.
• Sterilization: Total destruction of all microbes; processes include autoclaving, incineration, and chemical sterilization.

Chemical Terms

• Antiseptic: Reduces microbes on living tissue (e.g., iodine, alcohol).
• Disinfectants: Destroys most microbes on non-living surfaces (e.g., bleach).
• Degerming: Removal of microbes via mechanical means (e.g., handwashing).
• Bactericide: Destroys bacteria (e.g., heat, chemicals).
• Pasteurization: Heat treatment to reduce pathogens in food.

Physical Methods of Microbial Control

• Heat: Denatures proteins, used for moist heat (boiling, autoclaving) and dry heat sterilization.
• Radiation: Nonionizing (UV light) for surfaces; ionizing for deeper penetration.
• Refrigeration: Slows down microbial growth; freezing is more effective than refrigeration.
• Desiccation: Drying inhibits microbial growth.

Chapter 10: Antimicrobial Drugs

• Ideal Drug: Inexpensive, fast-acting, competitive against pathogens, harmless to host.
• Mechanisms of Action: Bacterial cell wall synthesis inhibition, protein synthesis disruption, and metabolic pathway interference.
• Antibiotic Resistance: Methods bacteria use to evade antimicrobial action including enzyme production that deactivates drugs.

Chapter 7: Microbial Genetics

• DNA Replication: Semi-conservative process; involves enzymes like DNA polymerase.
• Transcription: DNA to mRNA in the nucleus.
• Translation: mRNA is read by ribosomes to make proteins.
• Gene Transfer: Includes conjugation (plasmid exchange), transformation (uptake of DNA), and transduction (viral DNA transfer).