MRCS Part A Microbiology Syllabus

Microbiology syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Microbiology in MRCS Part A, not a summary of it.

1. 1

   Introduction to Microbiology

   3 topics

   • History of Microbiology
     • Early Discoveries
     • Golden Age of Microbiology
     • Modern Microbiology
   • Classification of Microorganisms
     • Bacteria
     • Viruses
     • Fungi
     • Protozoa
     • Algae
   • Microscopy
     • Light Microscopy
     • Electron Microscopy
     • Fluorescence Microscopy
2. 2

   Bacteriology

   4 topics

   • Bacterial Structure
     • Cell Wall
     • Cell Membrane
     • Cytoplasm
     • Flagella
     • Pili
     • Spores
   • Bacterial Physiology
     • Growth and Reproduction
     • Metabolism
     • Genetic Exchange
   • Pathogenic Bacteria
     • Gram-Positive Bacteria
     • Gram-Negative Bacteria
     • Mycobacteria
     • Spirochetes
   • Bacterial Infections
     • Respiratory Infections
     • Gastrointestinal Infections
     • Skin and Soft Tissue Infections
     • Systemic Infections
3. 3

   Virology

   4 topics

   • Virus Structure
     • Capsid
     • Envelope
     • Genome
   • Virus Replication
     • Attachment and Entry
     • Genome Replication
     • Assembly and Release
   • Pathogenic Viruses
     • DNA Viruses
     • RNA Viruses
     • Retroviruses
   • Viral Infections
     • Respiratory Infections
     • Gastrointestinal Infections
     • Neurological Infections
     • Systemic Infections
4. 4

   Mycology

   4 topics

   • Fungal Structure
     • Cell Wall
     • Cell Membrane
     • Hyphae
     • Spores
   • Fungal Physiology
     • Growth and Reproduction
     • Metabolism
   • Pathogenic Fungi
     • Yeasts
     • Molds
     • Dimorphic Fungi
   • Fungal Infections
     • Superficial Mycoses
     • Cutaneous Mycoses
     • Subcutaneous Mycoses
     • Systemic Mycoses
5. 5

   Parasitology

   4 topics

   • Protozoa
     • Amoebae
     • Flagellates
     • Ciliates
     • Sporozoa
   • Helminths
     • Nematodes
     • Trematodes
     • Cestodes
   • Ectoparasites
     • Lice
     • Mites
     • Fleas
     • Ticks
   • Parasitic Infections
     • Intestinal Infections
     • Blood and Tissue Infections
     • Vector-Borne Infections
6. 6

   Immunology

   4 topics

   • Innate Immunity
     • Physical Barriers
     • Cellular Defenses
     • Inflammation
   • Adaptive Immunity
     • Humoral Immunity
     • Cell-Mediated Immunity
     • Immunological Memory
   • Immune Response to Infections
     • Bacterial Infections
     • Viral Infections
     • Fungal Infections
     • Parasitic Infections
   • Immunopathology
     • Hypersensitivity Reactions
     • Autoimmune Diseases
     • Immunodeficiency Disorders
7. 7

   Microbial Genetics

   4 topics

   • Genetic Material
     • DNA Structure
     • RNA Structure
   • Gene Expression
     • Transcription
     • Translation
     • Regulation of Gene Expression
   • Genetic Variation
     • Mutations
     • Horizontal Gene Transfer
   • Genetic Engineering
     • Recombinant DNA Technology
     • CRISPR-Cas9
8. 8

   Antimicrobial Agents

   4 topics

   • Antibiotics
     • Mechanisms of Action
     • Spectrum of Activity
     • Resistance Mechanisms
   • Antiviral Agents
     • Mechanisms of Action
     • Resistance Mechanisms
   • Antifungal Agents
     • Mechanisms of Action
     • Resistance Mechanisms
   • Antiparasitic Agents
     • Mechanisms of Action
     • Resistance Mechanisms
9. 9

   Clinical Microbiology

   4 topics

   • Specimen Collection and Transport
     • Types of Specimens
     • Transport Media
   • Diagnostic Techniques
     • Microscopy
     • Culture Methods
     • Molecular Methods
     • Serological Methods
   • Antimicrobial Susceptibility Testing
     • Disk Diffusion Method
     • Broth Dilution Method
     • E-test
   • Infection Control
     • Sterilization and Disinfection
     • Hospital-Acquired Infections
     • Antibiotic Stewardship

Microbiology flashcards for MRCS Part A

24 of 52 cards from the Microbiology deck — real questions with worked answers.

1. Who is regarded as the 'Father of Microbiology' and what did he first observe using his single-lens microscopes in the 1670s?

   Antonie van Leeuwenhoek; he was the first to observe and describe live microorganisms ('animalcules'), including bacteria and protozoa.

2. State Koch's postulates, the four criteria used to establish that a specific microbe causes a specific disease.

   1) The organism is found in all cases of the disease and absent in healthy hosts. 2) It can be isolated and grown in pure culture. 3) The cultured organism reproduces the disease when introduced into a healthy susceptible host. 4) It can be re-isolated from that experimentally infected host.

3. What key contributions did Louis Pasteur make to microbiology?

   He disproved spontaneous generation, developed pasteurisation, established the germ theory of disease, and pioneered attenuated vaccines (e.g. rabies, anthrax, chicken cholera).

4. In the three-domain classification system of Carl Woese, what are the three domains and on which molecule is the classification based?

   Bacteria, Archaea, and Eukarya; the classification is based on comparison of small-subunit (16S/18S) ribosomal RNA sequences.

5. How do prokaryotic cells differ fundamentally from eukaryotic cells?

   Prokaryotes lack a membrane-bound nucleus and membrane-bound organelles, have 70S ribosomes and a single circular chromosome; eukaryotes have a true nucleus, membrane-bound organelles, 80S ribosomes and linear chromosomes.

6. Give the standard order of the biological taxonomic hierarchy from broadest to most specific.

   Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

7. What is the limit of resolution of the light microscope and roughly what magnification does it achieve?

   Resolution limit is about $0.2\ \mu m$ (200 nm), with useful magnification up to approximately $\times 1000$ to $\times 1500$.

8. State the Abbe equation for the resolving power (d) of a microscope and define its terms.

   $$d = \frac{0.61\,\lambda}{NA}$$ where $\lambda$ is the wavelength of light and $NA$ is the numerical aperture of the objective lens. Smaller $d$ means better resolution.

9. Why does the electron microscope achieve far higher resolution than the light microscope?

   It uses a beam of electrons whose wavelength is vastly shorter than visible light, giving resolution down to about $0.2\ nm$ and magnifications over $\times 100{,}000$.

10. Outline the steps and key reagents of the Gram stain.

    1) Crystal violet (primary stain). 2) Gram's iodine (mordant). 3) Alcohol/acetone (decolouriser). 4) Safranin (counterstain). Gram-positive cells retain crystal violet and appear purple; Gram-negative cells lose it and appear pink/red.

11. Compare the cell wall of Gram-positive and Gram-negative bacteria.

    Gram-positive: thick peptidoglycan layer with teichoic acids, no outer membrane. Gram-negative: thin peptidoglycan layer plus an outer membrane containing lipopolysaccharide (LPS/endotoxin) and a periplasmic space.

12. What is the chemical nature and function of bacterial peptidoglycan (murein)?

    A polymer of alternating N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) cross-linked by peptide bridges; it provides cell wall rigidity and osmotic protection. It is the target of penicillins and lysozyme.

13. What is bacterial LPS (lipopolysaccharide) and which component is toxic?

    LPS is the major molecule of the Gram-negative outer membrane, composed of O-antigen, core polysaccharide and lipid A. Lipid A is the toxic endotoxin responsible for fever and septic shock.

14. Distinguish bacterial endotoxin from exotoxin.

    Endotoxin is the lipid A of LPS, part of the Gram-negative cell wall, heat-stable, weakly immunogenic, causing fever/shock. Exotoxins are secreted proteins (Gram +/-), often heat-labile, highly immunogenic, and convertible to toxoids for vaccines.

15. What is a bacterial spore (endospore), which genera produce them, and why are they clinically important?

    A dormant, highly resistant dehydrated structure containing dipicolinic acid and DNA. Produced by Bacillus and Clostridium. They resist heat, desiccation and disinfectants, surviving standard sterilisation and causing disease (e.g. tetanus, anthrax).

16. Describe the classification of bacteria by shape.

    Cocci (spherical), bacilli (rods), spirilla/spirochaetes (spiral/helical), and vibrios (comma-shaped). Arrangements include diplo-, strepto- (chains) and staphylo- (clusters).

17. What is the function of bacterial fimbriae/pili versus flagella?

    Fimbriae (common pili) mediate adhesion to surfaces; the sex pilus mediates conjugation/DNA transfer. Flagella provide motility.

18. Define the four phases of the bacterial growth curve.

    Lag phase (adaptation, no division), log/exponential phase (maximal division), stationary phase (growth = death as nutrients deplete), and death/decline phase (net cell death).

19. Give the exponential growth equation relating cell number to generation number.

    $$N = N_{0} \times 2^{n}$$ where $N_{0}$ is the initial number, $n$ is the number of generations, and $N$ is the final number of cells.

20. Classify bacteria according to their oxygen requirements.

    Obligate aerobes (need $\ce{O2}$), obligate anaerobes (killed by $\ce{O2}$), facultative anaerobes (grow with or without $\ce{O2}$), microaerophiles (need low $\ce{O2}$), and aerotolerant anaerobes (tolerate but don't use $\ce{O2}$).

21. Name the three mechanisms of horizontal gene transfer in bacteria.

    Transformation (uptake of free/naked DNA), transduction (transfer via bacteriophage), and conjugation (direct transfer via a sex pilus/plasmid).

22. What are the major mechanisms of bacterial antibiotic resistance?

    Enzymatic drug inactivation (e.g. beta-lactamases), alteration of the drug target, decreased drug uptake/reduced permeability, and increased efflux pump activity.

23. Which coagulase-positive coccus is a common cause of wound infection, abscesses and is often methicillin-resistant?

    Staphylococcus aureus (MRSA when methicillin-resistant); Gram-positive, catalase-positive, coagulase-positive cocci in clusters.

24. Which Gram-positive organism causes gas gangrene, and what is its key laboratory feature?

    Clostridium perfringens; an anaerobic, spore-forming Gram-positive bacillus that produces alpha-toxin (lecithinase) causing myonecrosis and gas in tissues.

See more Microbiology flashcards →

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