Fall Semester 2025: Final Exam Study Guide Part 3 of 3

FINAL EXAM STUDY GUIDE PART 3 OF 3: NEW MATERIAL

New Disease Note Cards

  • Understand the causative agents for the following diseases:

    • Bubonic Plague: Yersinia pestis

    • Toxoplasmosis: Toxoplasma gondii

    • Cat Scratch Disease: Bartonella henselae

Historical Figures of Microbiology

  • Review significant historical figures in microbiology and their contributions:

    • Robert Hooke:

    • Known for his pioneering work in cell theory, he coined the term "cell" after observing cork under a microscope.

    • Antoni van Leeuwenhoek:

    • First to observe and describe microscopic organisms, known as the "father of microbiology".

    • John Needham:

    • Conducted experiments pertaining to spontaneous generation which claimed that microbes could arise from non-living matter.

    • Francesco Redi:

    • Challenged the idea of spontaneous generation with his meat jar experiments, demonstrating that maggots came from eggs laid by flies.

    • Lazzaro Spallanzani:

    • Supported the biogenesis theory and disproved Needham’s conclusions by showing that sealed containers with broth did not develop microbial life.

    • Louis Pasteur:

    • Developed the germ theory of disease and pasteurization; demonstrated that microorganisms could cause disease.

    • Robert Koch:

    • Established a series of principles known as Koch's postulates that are used to establish a causative relationship between a microbe and a disease.

    • John Snow:

    • Investigated the cholera outbreak in London, establishing epidemiology as a field of study and linking water supply to disease spread.

    • Ignaz Semmelweis:

    • Advocated for hand hygiene in medical settings to reduce maternal deaths from puerperal fever.

    • Joseph Lister:

    • Introduced antiseptic techniques in surgery, significantly reducing infection rates.

    • Remak vs. Virchow:

    • Discuss the debate between Remak and Virchow concerning cellular pathology and the origin of cells. Virchow famously stated, "Omnis cellula e cellula" (All cells come from cells).

Germ Theory of Disease

  • Be familiar with the Germ Theory of Disease:

    • The theory posits that specific microorganisms are the cause of specific diseases. This marked a significant advancement in understanding the link between microbes and illness.

Biosafety Levels (BSL)

  • Understand the biosafety levels established by the Centers for Disease Control and Prevention (CDC):

    • BSL-1:

    • Non-pathogenic E. coli (K12 = the classic common, harmless lab strain)

    • BSL-2:

    • Includes Staphylococcus aureus, Pseudomonas aeruginosa, and HIV. These organisms pose moderate hazards to personnel and the environment.

    • BSL-3:

    • Mycobacterium tuberculosis (causes TB which can be transmitted through aerosols).

    • BSL-4:

    • Highly pathogenic and dangerous agents such as Ebola virus, Hantavirus, and Marburg virus.

Personal Protective Equipment (PPE)

  • Understand the escalation of required PPE corresponding to increasing biosafety levels.

  • Recognize the additional features and instrumentation necessary to outfit an infectious disease lab appropriately as the BSL increases.

Biofilm Formation

  • Refer to Part 1 of the Study Guide for details on biofilm formation, as it may be relevant for questions pertaining to this topic.

Hemolysis Patterns

  • Understand the function of Red Blood Cells (RBCs) and the structure of hemoglobin:

    • RBCs transport oxygen from the lungs to body tissues and bring carbon dioxide back to the lungs.

    • Hemoglobin is the protein in RBCs that carries oxygen; it consists of four subunits (two alpha and two beta chains), each bound to a heme group that contains iron.

  • Be able to distinguish between the various types of hemolysis:

    • Alpha Hemolysis: Partial hemolysis; characterized by a greenish coloration in the agar due to the reduction of hemoglobin to methemoglobin.

    • Beta Hemolysis: Complete hemolysis; shown as clear zones around colonies as the bacteria fully lyse the RBCs and degrade hemoglobin.

    • Gamma Hemolysis: No hemolysis; the medium remains unchanged.

  • Important to recognize each type of hemolysis and what it implies:

    • Hemolysis patterns are crucial for bacterial identification in clinical settings, aiding in determining treatment strategies for patients.

Control of Microorganisms by Heat

  • Familiarize with methods for controlling microorganisms by heat:

    • Direct Flame: Excellent for sterilizing instruments; high effectiveness in killing microbes, especially spores.

    • Boiling: Effective for most pathogens, but not necessarily for spores.

    • Dry Heat (Oven): Generally requires higher temperatures for extended periods.

    • Moist Heat Under Pressure (Autoclave):

    • Related temperature: 121°C

    • Required time exposure: 15-30 minutes at this temperature

    • Extent of pressure: 15 psi (pounds per square inch)

    • This method is very successful at killing microorganisms, including spores.

  • Markers for effective sterilization methods include:

    • “Does it kill spores?”

Other Methods of Control

  • Types of filters:

    • Understand pros and cons related to various filtering methods used in microbiology.

  • UV Light:

    • Typical uses include surface disinfection; effective against many microbes but generally not effective for spores.

  • Ultrasonic Waves (US):

    • Commonly used for cleaning delicate instruments; can break down microbial populations effectively.