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BDS Microbiology Syllabus

The Microbiology syllabus for BDS in full: 9 chapters, 35 topics and 111 sub-topics, every one listed below, plus 51 Microbiology flashcards with answers.

9Chapters

35Topics

111Sub-topics

51Flashcards

Microbiology syllabus: all 9 chapters

Expand any chapter to see its topics and sub-topics.

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
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
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
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
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
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
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
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
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

BDS Microbiology flashcards — 51 questions with answers

Who is regarded as the "Father of Microbiology" and what did he first observe using his single-lens microscopes?
Antonie van Leeuwenhoek; he first observed and described live microorganisms ("animalcules") such as bacteria and protozoa from pond water, plaque and other samples in the 1670s.
State the germ theory of disease and name the scientist most associated with proving it.
The germ theory states that specific microorganisms are the cause of specific infectious diseases. Louis Pasteur provided key proof (disproving spontaneous generation), and Robert Koch established the causal link experimentally.
List Koch's postulates for establishing that a microbe causes a disease.
1) The microbe is present in all cases of the disease and absent in healthy hosts. 2) It can be isolated and grown in pure culture. 3) The cultured microbe causes the disease when inoculated into a healthy susceptible host. 4) The same microbe is re-isolated from the newly diseased host.
In the three-domain classification system, into which domains are cellular organisms divided?
Bacteria, Archaea, and Eukarya.
What is binomial nomenclature and how is a species name written (give the format)?
A two-part Latin naming system: Genus (capitalized) + species (lowercase), italicized or underlined, e.g. Staphylococcus aureus; often abbreviated after first use as S. aureus.
Define resolving power (resolution) of a microscope and give the formula for the limit of resolution.
Resolution is the smallest distance at which two points can be distinguished as separate. The limit of resolution is $d = \frac{0.61\,\lambda}{NA}$, where $\lambda$ is the wavelength of light and $NA$ is the numerical aperture.
Write the formula for the numerical aperture (NA) of a microscope objective.
$NA = n \sin\theta$, where $n$ is the refractive index of the medium between specimen and lens and $\theta$ is half the angular aperture of the lens.
How is total magnification of a compound light microscope calculated?
$M_{total} = M_{objective} \times M_{ocular}$ (objective lens magnification multiplied by eyepiece magnification), e.g. $100 \times 10 = 1000\times$.
Why does the oil-immersion objective use immersion oil, and what is the approximate refractive index of the oil?
Immersion oil (refractive index $n \approx 1.515$, matching glass) replaces air, preventing light refraction/loss at the glass-air interface, thereby increasing the numerical aperture and resolution at high magnification (100x).
Compare the resolution of a light microscope versus an electron microscope.
Light microscope: resolution limit ~$0.2\ \mu m$ (200 nm). Electron microscope: resolution down to ~$0.2\ nm$ because electrons have a far shorter wavelength than visible light, giving roughly 1000x better resolution.
Describe the steps of the Gram stain and the results for Gram-positive vs Gram-negative bacteria.
Steps: crystal violet (primary), Gram's iodine (mordant), alcohol/acetone (decolorizer), safranin (counterstain). Gram-positive retain crystal violet and appear purple/violet; Gram-negative lose it and take up safranin, appearing pink/red.
What is the key structural difference between the cell walls of Gram-positive and Gram-negative bacteria?
Gram-positive have a thick peptidoglycan layer with teichoic acids and no outer membrane; Gram-negative have a thin peptidoglycan layer plus an outer membrane containing lipopolysaccharide (LPS).
What is the chemical composition of peptidoglycan (murein)?
A polymer of alternating N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) sugars, cross-linked by short peptide chains (tetrapeptides) attached to NAM.
What is the biological significance of lipopolysaccharide (LPS) / endotoxin in Gram-negative bacteria?
LPS is the outer-membrane endotoxin; its lipid A component triggers fever, inflammation and can cause septic shock when released. It also contributes to the antigenic O-specific side chains.
Distinguish the bacterial capsule from the cell wall and state the capsule's main function.
The capsule is an outer polysaccharide (sometimes polypeptide) layer external to the cell wall. It is a virulence factor that resists phagocytosis and aids adherence; it is not required for growth.
Compare bacterial flagella, pili (fimbriae), and sex pili by function.
Flagella: locomotion/motility. Fimbriae (common pili): adherence/attachment to surfaces. Sex (F) pilus: conjugation, transferring DNA between bacteria.
What is a bacterial endospore and which two genera are the most important spore-formers?
A dormant, highly resistant dehydrated structure formed by some bacteria to survive harsh conditions (heat, desiccation, chemicals). The key genera are Bacillus and Clostridium.
Classify bacterial cell shapes with an example arrangement for each.
Cocci (spheres, e.g. clusters=staphylo, chains=strepto), bacilli (rods), spirilla/spirochetes (spiral/helical), vibrio (comma-shaped).
Classify bacteria by oxygen requirement into the main four groups.
Obligate aerobes (need O2), obligate anaerobes (killed by O2), facultative anaerobes (grow with or without O2), and microaerophiles (need low O2); aerotolerant anaerobes tolerate but don't use O2.
Write the exponential growth equation for a bacterial population and define the terms.
$N_t = N_0 \times 2^{n}$, where $N_t$ is the number of cells after $n$ generations, $N_0$ is the initial number, and $n$ is the number of divisions. Also $n = \frac{t}{g}$ where $g$ is the generation (doubling) time.

Show the other 31 Microbiology flashcards

Name and describe the four phases of the bacterial growth curve.
Lag phase (adaptation, no division), log/exponential phase (maximal division), stationary phase (division = death, nutrients limiting), and death/decline phase (cells die exponentially).
What is the difference between bacterial transformation, transduction, and conjugation?
Transformation: uptake of free naked DNA from the environment. Transduction: DNA transfer via a bacteriophage. Conjugation: direct cell-to-cell DNA transfer through a sex pilus.
Differentiate exotoxins from endotoxins.
Exotoxins: secreted proteins from (mainly) Gram-positive and some Gram-negative bacteria, highly potent, often specific, heat-labile, toxoid-able. Endotoxins: LPS (lipid A) of Gram-negative outer membrane, released on lysis, heat-stable, cause fever/shock, less potent.
Which bacterium causes tuberculosis, and what special staining property does it have?
Mycobacterium tuberculosis; it is acid-fast (stained by the Ziehl-Neelsen method) due to mycolic acids in its cell wall, resisting decolorization by acid-alcohol.
Name the causative bacteria of tetanus, botulism, and gas gangrene.
Tetanus: Clostridium tetani; botulism: Clostridium botulinum; gas gangrene: Clostridium perfringens.
Which bacterium is the leading cause of peptic ulcers and gastric cancer, and how does it survive stomach acid?
Helicobacter pylori; it produces urease, which hydrolyzes urea to ammonia ($\ce{CO(NH2)2 + H2O -> 2NH3 + CO2}$), neutralizing gastric acid around the organism.
List the classic cardinal signs of acute inflammation seen in bacterial infection.
Rubor (redness), calor (heat), tumor (swelling), dolor (pain), and functio laesa (loss of function).
Define bacteremia, septicemia, and toxemia.
Bacteremia: presence of bacteria in the blood. Septicemia (sepsis): active multiplication of bacteria in blood causing systemic illness. Toxemia: presence of bacterial toxins in the blood.
What is the general mechanism of action of penicillin against bacteria?
Penicillin (a beta-lactam) inhibits the transpeptidase enzymes (penicillin-binding proteins) that cross-link peptidoglycan, blocking cell-wall synthesis and causing lysis of growing bacteria.
Describe the basic structural components of a virus (virion).
A nucleic acid genome (DNA or RNA) surrounded by a protein coat (capsid, made of capsomeres); together the nucleocapsid. Some viruses have an outer lipid envelope with glycoprotein spikes.
What are the three main types of viral capsid symmetry?
Icosahedral (cubic) symmetry, helical symmetry, and complex symmetry (e.g. bacteriophages with head-and-tail structure).
According to the Baltimore classification, how are viruses grouped?
By genome type and replication strategy: dsDNA, ssDNA, dsRNA, (+)ssRNA, (−)ssRNA, ssRNA reverse-transcribing (retroviruses), and dsDNA reverse-transcribing viruses (seven classes).
Compare an enveloped virus with a naked (non-enveloped) virus in terms of environmental resistance.
Naked viruses lack a lipid envelope, are more resistant to drying, acids, detergents and disinfectants. Enveloped viruses have a lipid membrane, are more susceptible to these agents (envelope is essential for infectivity).
List the main stages of the viral replication cycle in order.
1) Attachment (adsorption), 2) Penetration/entry, 3) Uncoating, 4) Biosynthesis (genome replication and protein synthesis), 5) Assembly (maturation), 6) Release (lysis or budding).
What enzyme do retroviruses (e.g. HIV) use, and what reaction does it catalyze?
Reverse transcriptase (RNA-dependent DNA polymerase); it synthesizes complementary DNA from the viral RNA genome, which is then integrated into host DNA by integrase.
Distinguish the lytic cycle from the lysogenic cycle of a bacteriophage.
Lytic cycle: the phage replicates immediately and lyses the host cell to release progeny. Lysogenic cycle: the phage DNA integrates into the host genome as a prophage and replicates passively until induced into the lytic cycle.
Which virus causes AIDS, what cells does it target, and via which receptor?
HIV (Human Immunodeficiency Virus, a retrovirus) targets CD4+ T-helper lymphocytes (and macrophages) by binding the CD4 receptor plus a co-receptor (CCR5 or CXCR4).
Name the herpesviruses responsible for cold sores, genital herpes, chickenpox/shingles, and infectious mononucleosis.
HSV-1 (oral/cold sores), HSV-2 (genital herpes), Varicella-zoster virus (chickenpox and shingles), and Epstein-Barr virus (infectious mononucleosis).
Which hepatitis viruses are transmitted by the faecal-oral route versus by blood/body fluids?
Faecal-oral: Hepatitis A and E. Blood/body fluids (parenteral/sexual): Hepatitis B, C, and D.
What is antigenic drift versus antigenic shift in influenza virus?
Antigenic drift: minor, gradual point mutations in H and N genes causing seasonal epidemics. Antigenic shift: major abrupt reassortment of genome segments producing a new subtype, potentially causing pandemics.
Distinguish a latent viral infection from a persistent (chronic) infection.
Latent infection: the virus remains dormant with no production of infectious particles until reactivation (e.g. herpesviruses). Persistent/chronic infection: continuous low-level production of virus over a long period (e.g. hepatitis B/C).
Describe the two main morphological forms of fungi and define a dimorphic fungus.
Yeasts (single, round/oval cells reproducing by budding) and molds (filamentous hyphae forming a mycelium). Dimorphic fungi grow as mold at ~25°C (environment) and as yeast at ~37°C (in the body), e.g. Histoplasma.
What is the main structural component of the fungal cell wall, distinguishing it from bacteria?
Chitin (a polymer of N-acetylglucosamine), along with glucans and mannoproteins. Fungi lack peptidoglycan, and their cell membrane contains ergosterol instead of cholesterol.
Differentiate septate from coenocytic (aseptate) hyphae.
Septate hyphae have cross-walls (septa) dividing the filament into cells; coenocytic (aseptate) hyphae lack septa and contain multinucleate cytoplasm in a continuous tube.
Why does the antifungal drug amphotericin B selectively target fungi, and what fungal molecule does it bind?
It binds ergosterol, the sterol in fungal cell membranes (absent in human cells, which use cholesterol), forming pores that cause leakage of ions and cell death; azoles instead block ergosterol synthesis.
Name the fungal genus that causes oral/vaginal thrush and the most common species.
Candida, most commonly Candida albicans, an opportunistic dimorphic yeast causing thrush (oral candidiasis), vaginitis and systemic candidiasis in immunocompromised hosts.
Which fungus causes cryptococcal meningitis, and what special stain highlights its capsule?
Cryptococcus neoformans; its thick polysaccharide capsule is highlighted by India ink preparation (negative stain) of cerebrospinal fluid.
What are dermatophytes and give the three main genera causing ringworm (tinea).
Dermatophytes are keratinophilic fungi that infect skin, hair and nails. The three genera are Trichophyton, Microsporum, and Epidermophyton.
Which protozoan causes malaria, what genus is it, and what is the vector?
Plasmodium (species include P. falciparum, P. vivax, P. ovale, P. malariae); it is transmitted by the bite of the female Anopheles mosquito.
Classify the causative agents and distinguishing features of amoebic versus bacillary dysentery.
Amoebic dysentery: caused by the protozoan Entamoeba histolytica (flask-shaped ulcers, blood/mucus, gradual onset). Bacillary dysentery: caused by the bacterium Shigella (acute, more inflammatory).
Give one example each of the major helminth groups: nematode, cestode, and trematode.
Nematode (roundworm): Ascaris lumbricoides. Cestode (tapeworm): Taenia solium. Trematode (fluke): Schistosoma species. Also compare Ectoparasites such as Sarcoptes scabiei (mite causing scabies) and lice (Pediculus), which live on the host surface and can act as disease vectors.

Same Microbiology syllabus in other exams

The Microbiology outline above is identical in these 3 exams:

BDS Microbiology FAQ

What is in the BDS Microbiology syllabus?

BDS Microbiology is split into 9 chapters: Introduction to Microbiology, Bacteriology, Virology, Mycology, Parasitology, Immunology, Microbial Genetics, Antimicrobial Agents and Clinical Microbiology. Together they contain 35 topics and 111 sub-topics.

How many chapters are in BDS Microbiology?

9 chapters, containing 35 topics and 111 sub-topics. The largest chapter is Bacteriology, with 4 topics.

Are there flashcards for BDS Microbiology?

Yes — a 51-card Microbiology deck, printed in full in the flashcards section of this page and available in the Examius app with spaced repetition. The free plan covers one exam of your choice, including its flashcards; Examius Pro, a one-time purchase, unlocks every other exam and deck.