Microbiology Exam 1 Study Guide: Chapters 1–6

Chapter 1: Foundations of Microbiology

Scientific Contributions and Historical Figures

This section covers the major scientists who shaped microbiology and their discoveries.

• Antonie van Leeuwenhoek: First to observe and describe microorganisms using a microscope.

• Joseph Lister: Developed antiseptic techniques in surgery.

• Ignaz Semmelweis: Introduced handwashing to prevent puerperal fever.

• Edward Jenner: Developed the first vaccine (smallpox).

• Florence Nightingale: Pioneered infection control in nursing.

Prokaryotic vs. Eukaryotic Organisms

• Prokaryotes: Lack a nucleus and membrane-bound organelles (e.g., Bacteria and Archaea).

• Eukaryotes: Possess a nucleus and organelles (e.g., Fungi, Protozoa, Algae).

Scientific Method and Spontaneous Generation

• Scientific Method: Systematic approach to research involving observation, hypothesis, experimentation, and conclusion.

• Spontaneous Generation: The disproven idea that life arises from nonliving matter.

• Louis Pasteur: Disproved spontaneous generation with swan-neck flask experiments.

Robert Koch's Contributions

• Koch's Postulates: Criteria to establish a causative relationship between a microbe and a disease.

• Contributions include development of pure culture techniques and identification of causative agents of diseases.

Chapter 2: Chemical Foundations and Nucleic Acids

pH Scale

The pH scale measures the acidity or alkalinity of a solution, ranging from 0 (acidic) to 14 (basic).

• pH = -log[H+]

• Biological systems typically function near neutral pH (around 7).

Nucleotides and Nucleic Acids

• Nucleotides: Building blocks of nucleic acids, composed of a sugar, phosphate, and nitrogenous base.

• Nitrogenous Bases: Adenine, Thymine, Cytosine, Guanine, and Uracil.

• Classes of Nucleic Acids:

  • DNA: Stores genetic information.

  • RNA: Involved in protein synthesis and gene regulation.

Chapter 3: Cell Structure and Function

Major Processes of Living Cells

• Includes metabolism, growth, reproduction, and response to stimuli.

Prokaryotic vs. Eukaryotic Cell Walls and Membranes

• Prokaryotic Cell Walls: Usually contain peptidoglycan (in bacteria).

• Eukaryotic Cell Walls: Found in fungi and plants; composed of cellulose or chitin.

• Cytoplasmic Membranes: Phospholipid bilayer present in all cells.

Glycocalyces and Slime Layers

• Glycocalyx: Gelatinous, sticky substance outside the cell wall; protects and aids in adherence.

• Slime Layer: Loosely attached glycocalyx; helps in biofilm formation.

Bacterial Flagella and Fimbriae

• Flagella: Long, whip-like structures for motility.

• Pili: Short, hair-like appendages for attachment and conjugation.

• Fimbriae: Short, numerous projections for adherence.

Gram Staining and Cell Wall Types

• Gram-Positive: Thick peptidoglycan layer, stains purple.

• Gram-Negative: Thin peptidoglycan layer, outer membrane, stains pink.

• Acid-Fast Bacteria: Waxy cell wall, resist decolorization (e.g., Mycobacterium).

Ribosomes and Endosymbiotic Theory

• Ribosomes: Sites of protein synthesis; prokaryotic (70S) vs. eukaryotic (80S).

• Endosymbiotic Theory: Explains origin of mitochondria and chloroplasts from ancestral prokaryotes.

Phospholipid Bilayer and Cytoplasmic Membrane

• Phospholipid Bilayer: Provides selective permeability and fluidity to membranes.

• Cytoplasmic Membrane: Controls movement of substances in and out of the cell.

Cytoplasmic Membrane Transport

• Passive Processes: Diffusion, osmosis, facilitated diffusion.

• Active Processes: Active transport, group translocation.

Bacterial Cytoplasm

• Contains cytosol, inclusions, and sometimes endospores.

Chapter 4: Microbial Classification and Identification

Staining Techniques

• Simple Stain: Uses a single dye to highlight cells.

• Gram Stain: Differentiates bacteria by cell wall structure.

• Acid-Fast Stain: Identifies bacteria with waxy cell walls.

• Endospore Stain: Detects bacterial endospores.

Binomial Nomenclature

• System of naming organisms using genus and species (e.g., Escherichia coli).

Three Domains of Life

• Bacteria

• Archaea

• Eukarya

Microbial Identification Procedures

• Includes staining, culturing, biochemical tests, and molecular methods.

Chapter 5: Microbial Metabolism

Metabolism, Anabolism, and Catabolism

• Metabolism: All chemical reactions in a cell.

• Anabolism: Building complex molecules from simpler ones (requires energy).

• Catabolism: Breaking down molecules to release energy.

ATP Phosphorylation

• ATP: Main energy currency of the cell.

• Phosphorylation adds a phosphate group to ADP to form ATP.

Enzyme Activity and Inhibition

• Enzymes: Biological catalysts that speed up reactions.

• Activation Energy: Minimum energy required for a reaction.

• Competitive Inhibition: Inhibitor competes with substrate for active site.

• Noncompetitive Inhibition: Inhibitor binds elsewhere, altering enzyme function.

Glycolysis, Krebs Cycle, Electron Transport Chain

• Glycolysis: Converts glucose to pyruvate, producing ATP and NADH.

• Krebs Cycle: Oxidizes acetyl-CoA, generating ATP, NADH, and FADH2.

• Electron Transport Chain: Transfers electrons to produce ATP via oxidative phosphorylation.

Fermentation and Respiration

• Fermentation: Anaerobic process producing ATP and useful products (e.g., ethanol, lactic acid).

• Respiration: Aerobic process yielding more ATP.

Photosynthesis

• Photosynthesis: Conversion of light energy to chemical energy in autotrophs.

• Key structures: chlorophyll, thylakoid membranes.

Chapter 6: Microbial Growth and Nutrition

Organism Classification by Carbon and Energy Source

• c

Oxygen Requirements

• Aerobes: Require oxygen.

• Anaerobes: Do not require oxygen.

• Facultative Anaerobes: Can grow with or without oxygen.

• Microaerophiles: Require low oxygen levels.

Toxic Forms of Oxygen and Protection

• Reactive oxygen species (ROS) can damage cells.

• Microbes produce enzymes like catalase and superoxide dismutase to neutralize ROS.

Nitrogen Fixation

• Nitrogen Fixation: Conversion of atmospheric nitrogen (N2) to ammonia (NH3).

• Important for supplying usable nitrogen to living organisms.

Microbial Growth and Biofilms

• Biofilm: Community of microorganisms attached to a surface, protected by extracellular matrix.

• Quorum Sensing: Cell-to-cell communication regulating biofilm formation.

Culturing Bacteria

• Streak Plate Method: Isolates pure colonies on agar plates.

• Culture Media Types: Selective, differential, enriched, and minimal media.

Bacterial Reproduction and Growth Curve

• Binary Fission: Main method of bacterial reproduction.

• Growth Curve Phases: Lag, log (exponential), stationary, and death phases.

Measuring Bacterial Reproduction

• Direct methods include plate counts and microscopic counts.

Additional info:

• Some details (e.g., specific examples, chemical equations) were inferred for completeness.