General Microbiology - Spring 2025 Final Exam Review

Flashcards for General Microbiology Final Exam Review

Microbiology

Study of microorganisms, differentiating characteristics of different types of organisms.

Prokaryotic Cells

Cells without a nucleus or other membrane-bound organelles.

Eukaryotic Cells

Cells with a nucleus and other membrane-bound organelles.

Cellular Commonalities

All cells have a plasma membrane, cytoplasm, DNA, and ribosomes in common.

Prokaryotic vs. Eukaryotic Genome

Prokaryotic: Single, circular chromosome. Eukaryotic: Multiple, linear chromosomes.

Decreasing Deaths by Infectious Diseases

Improved sanitation, antibiotics/antimicrobials, and vaccinations.

Nitrogen Fixation

Conversion of atmospheric nitrogen into ammonia, essential for plant growth.

Antimicrobial Resistant Bacteria

Acquired through overuse/misuse of antimicrobials, horizontal gene transfer, and natural selection.

Innate vs. Adaptive Immunity

Innate: Non-specific, rapid response. Adaptive: Specific, slower response involving memory.

Innate Immunity Examples

Mechanical (skin), chemical (enzymes), cellular (macrophages), microbial antagonism (normal flora).

Communicable vs. Non-Communicable Disease

Communicable: Transmitted from person to person. Non-communicable: Not transmitted from person to person.

Simple Stain vs. Differential Stain

Simple stain: Uses one dye to observe basic morphology. Differential stain: Uses multiple dyes to differentiate between organisms or structures.

Basic Dye/Stain

Positively charged dye that stains negatively charged cellular components.

Koch's Postulates

Set of criteria for proving that a specific organism causes a specific disease.

Differences Between Domains

Bacteria: Prokaryotic, peptidoglycan cell walls. Eukarya: Eukaryotic, various cell wall compositions. Archaea: Prokaryotic, unique cell walls.

Domain Classification

Determined by characteristics such as cell structure, metabolism, and genetics.

Evolution of Life on Earth

RNA world hypothesis, evolution of metabolic processes.

DNA Transformation

Uptake of naked DNA from the environment.

Tree Of Life

Shows evolutionary relationships between organisms based on genetic data.

rRNA in Building Tree of Life

Highly conserved, universally distributed, and contains enough genetic information to show relationships.

First Type of Metabolism to Evolve

Chemolithoautotrophy, then photoautotrophy.

First Autotrophs

Chemolithoautotrophs used inorganic compounds for energy and CO2 as a carbon source, while photoautotrophs use sunlight for energy and CO2 as a carbon source.

Great Oxidation Event

Increase in atmospheric oxygen due to photosynthetic organisms, leading to the formation of the ozone layer and aerobic respiration.

Archaea, Bacteria, and Eukarya Similarities/Differences

Archaea and Bacteria are prokaryotic, Eukarya is eukaryotic.

Ozone Shield Formation

Formed by the accumulation of oxygen in the atmosphere, protecting Earth from harmful UV radiation.

Taxonomy of Eukarya vs. Bacteria

Eukarya: Hierarchical, based on morphology and genetics. Bacteria: Based on 16S rRNA gene sequences and biochemical characteristics.

rRNA for Identification/Classification

16S rRNA in prokaryotes, 18S rRNA in eukaryotes.

Bacterial Cell Parts

Cell wall, cell membrane, cytoplasm, ribosomes, nucleoid, plasmid, pili, flagella, capsule, endospores.

Attraction of Basic vs. Acidic Dyes

Basic dyes are attracted to negatively charged molecules, while acidic dyes attracted to positively charged molecules.

Methodology for Differential Stains

Use of multiple dyes and a mordant to differentiate cellular structures or organisms.

Purpose of Differential Stains

Gram stain: differentiate Gram + and Gram - bacteria. Acid-fast stain: identify bacteria with mycolic acid in cell walls. Endospore stain: visualize endospores.

Gram Stain Differentiation

Based on differences in cell wall structure (peptidoglycan layer).

Gram + vs. Gram - Bacteria

Gram +: Thick peptidoglycan layer, teichoic acids. Gram -: Thin peptidoglycan layer, outer membrane with LPS.

Taxonomic Groups Containing Microbes

Bacteria, Archaea, Eukarya.

Glycocalyx

Outer layer of polysaccharides, functions include attachment, protection from phagocytosis, and biofilm formation. Slime layer: loosely attached. Capsule: tightly attached.

Pili vs. Flagella

Pili: Attachment and genetic transfer. Flagella: Motility.

Biofilms

Communities of microorganisms attached to a surface, important in infections and environmental processes.

Cilia vs. Flagella

Cilia: Short, numerous, involved in movement. Flagella: Long, few, involved in propulsion.

Domain-Specific Structures

Review specific structures and their presence in each domain.

Energy Transfer

Chemoheterotrophs: Chemical energy, organic carbon; Chemoautotrophs: Chemical energy, inorganic carbon; Photoautotrophs: Light energy, inorganic carbon; Photoheterotrophs: Light energy, organic carbon. Electron carriers: NAD+/NADH, FAD/FADH2. Electron acceptors: Oxygen, nitrate, sulfate.

Oxygenic vs. Anoxygenic Metabolism

Oxygenic: Oxygen is produced. Anoxygenic: Oxygen is not produced.

Aerobic Respiration vs. Anaerobic Respiration vs. Fermentation

Aerobic respiration uses oxygen as the final electron acceptor, anaerobic respiration uses other inorganic molecules, and fermentation uses organic molecules. Glycolysis is involved in all three, CAC and electron transport system in respiration.

Alcohol Fermentation vs. Lactic Acid Fermentation

Alcohol fermentation: Acetaldehyde is the final e- acceptor, products include ethanol and CO2. Lactic acid fermentation: Pyruvate is the final e- acceptor, product is lactic acid.

E. coli Respiration Types

E. coli can perform aerobic respiration, anaerobic respiration, and fermentation depending on available electron acceptors.

Biochemical Tests

Dehydrogenation: Removal of hydrogen. Decarboxylation: Removal of carboxyl group. Desulfurylation: Removal of sulfur. Urease production: Hydrolysis of urea. Positive results depend on specific test.

Photoautotroph Oxygen Use

Oxygenic when water is the electron donor, anoxygenic when other molecules are electron donors.

Calvin Cycle

Photoautotrophs and chemoautotrophs use the Calvin Cycle. CO2 + RuBP -> 2(3PG). Ribulose bisphosphate: CO2 acceptor. RubisCO: Catalyzes the first step. Phosphoribulokinase: Regenerates RuBP.

Nitrogen Fixation Components

Conversion of atmospheric nitrogen to ammonia. Nitrogenase complex: Dinitrogenase reductase and dinitrogenase. Dinitrogenase reductase transfers electrons, dinitrogenase reduces nitrogen.

Methods for Protecting Nitrogenase

Physical protection, temporal protection, protective proteins, compatible solutes.

Enzyme Affects

Temperature: Affects enzyme activity. pH: Affects enzyme structure and activity. Substrate concentration: Affects reaction rate. Inhibitors: Decrease enzyme activity.

Direct Measurements of Growth

Plate counts: Count colonies on plates. MPN method: Statistical estimation. Direct counts: Count cells under a microscope.

Indirect Methods of Estimating Numbers

Turbidity: Measures cloudiness. Metabolic activity: Measures production of metabolic end-products. Dry weight: Measures mass of cells.

Phases of Bacterial Growth

Lag phase: Adjustment. Log phase: Exponential growth. Stationary phase: Growth equals death. Death phase: Decline.

Decontamination

Removal of microorganisms.

Thermal Death Time

Time required to kill a specific number of microorganisms at a given temperature.

Decontamination & Antimicrobial Terminology

Sterilization, disinfection, antisepsis.

Factors Affecting Antimicrobials

Population size, temperature, pH, concentration of antimicrobial agent.

Disk-Diffusion Method

Evaluates the effectiveness of antimicrobials. Larger zone of inhibition means more effective antimicrobial.

Microbe Resistance (Least to Most)

Prions, endospores, mycobacteria, cysts of protozoa, vegetative protozoa, Gram-negative bacteria, fungi, viruses without envelopes, Gram-positive bacteria, viruses with envelopes.

Virus Life Cycle Sequence

Attachment, penetration, uncoating, replication, assembly, release.

Lytic vs. Lysogenic Pathways

Lytic: Host cell lysis. Lysogenic: Integration of viral DNA into host genome.

Viroids & Prions

Viroids: Small, circular RNA molecules that infect plants. Prions: Infectious proteins.

Genetic Information Flow

Replication: DNA synthesis. Transcription: RNA synthesis. Translation: Protein synthesis.

DNA Synthesis Process

DNA polymerase: Synthesizes DNA. Primase: Synthesizes RNA primers. DNA Pol III: Major replication enzyme. DNA Pol I: Replaces RNA primers with DNA. Ligase: Joins DNA fragments. Helicase: Unwinds DNA. DNA gyrase: Relieves supercoiling.

Genetic Elements

Chromosomes: Main genetic material. Plasmids: Extrachromosomal DNA. Transposable elements: Mobile genetic elements.

Transcription

RNA polymerase synthesizes RNA from a DNA template.

Transcriptional Units

Transcriptional units: DNA segments transcribed as a single unit. Operons: Genes transcribed together. Polycistronic mRNA: mRNA with multiple genes. ORFs: Open Reading Frames.

Ribosome Differences

Prokaryotes: 70S ribosomes. Eukaryotes: 80S ribosomes.

Translation

Codons: mRNA triplets. Anticodons: tRNA triplets. tRNA: Transfers amino acids. rRNA: Ribosomal RNA. Ribosomes: Protein synthesis.

Applied Microbology

Using microbes for a specific purpose.