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🌍 MRCS Part A · flashcards
MRCS Part A Microbiology Flashcards
52 question-and-answer cards covering Microbiology as it is examined in MRCS Part A. 24 of them are printed below, taken from across the deck — no signup, no paywall on the preview.
24 sample cards from the Microbiology deck
Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.
Name the classic clinical features (cardinal signs) of local infection/inflammation.
Rubor (redness), calor (heat), dolor (pain), tumor (swelling), and functio laesa (loss of function).
What is SIRS and how many criteria are required for its diagnosis?
Systemic Inflammatory Response Syndrome; diagnosed when at least 2 of: temperature >38 or <36 °C; heart rate >90 bpm; respiratory rate >20 or $PaCO_{2} < 4.3\ kPa$; white cell count >12 or <4 $\times 10^{9}/L$.
What organism causes tetanus and by what mechanism does its toxin act?
Clostridium tetani; tetanospasmin blocks release of inhibitory neurotransmitters (GABA/glycine) from spinal interneurons, causing unopposed muscle spasm (spastic paralysis).
Describe the basic structure of a virus.
A nucleic acid genome (DNA or RNA) enclosed in a protein capsid (made of capsomeres); together the nucleocapsid. Some viruses have an outer lipid envelope with glycoprotein spikes. Viruses lack their own metabolic machinery.
What are the two main types of viral capsid symmetry?
Helical symmetry (capsomeres arranged in a spiral around the nucleic acid) and icosahedral symmetry (20 triangular faces). Some viruses (e.g. poxviruses) are complex.
How does the Baltimore classification categorise viruses?
By genome type and replication strategy into 7 groups: dsDNA, ssDNA, dsRNA, (+)ssRNA, (-)ssRNA, ssRNA-RT (retroviruses), and dsDNA-RT.
List the stages of the viral replication cycle in order.
Attachment (adsorption), penetration/entry, uncoating, replication/biosynthesis (of nucleic acid and proteins), assembly (maturation), and release (by lysis or budding).
What enzyme is unique to retroviruses and what does it do?
Reverse transcriptase; an RNA-dependent DNA polymerase that transcribes the viral RNA genome into DNA, which is then integrated into the host genome by integrase.
Which cell type does HIV primarily infect via which receptor and co-receptors?
HIV infects CD4+ T-helper cells (and macrophages) by binding the CD4 receptor plus a chemokine co-receptor (CCR5 or CXCR4).
Compare the routes of transmission of hepatitis B and hepatitis A viruses.
Hepatitis B: blood-borne/parenteral, sexual and vertical transmission (DNA virus). Hepatitis A: faecal-oral route via contaminated food/water (RNA virus), causing self-limiting acute hepatitis.
Which virus causes chickenpox and shingles, and what is the mechanism linking the two conditions?
Varicella-zoster virus (VZV, a herpesvirus). Primary infection causes chickenpox; the virus becomes latent in dorsal root ganglia and reactivation causes shingles (herpes zoster).
What is a prion and how does it cause disease?
A prion is an infectious misfolded protein (PrP-Sc) with no nucleic acid. It induces normal cellular prion protein (PrP-C) to misfold, causing neurodegenerative spongiform encephalopathies (e.g. CJD). Prions resist standard sterilisation.
Which oncogenic virus is strongly associated with cervical carcinoma?
Human papillomavirus (HPV), particularly high-risk types 16 and 18; its E6 and E7 proteins inactivate p53 and Rb tumour suppressors.
Describe the general structure of a fungal cell and how it differs from a bacterium.
Fungi are eukaryotes with a nucleus and organelles, a cell wall of chitin and glucans, and a cell membrane containing ergosterol. Bacteria are prokaryotes with peptidoglycan walls and cholesterol-free membranes.
What is the target of azole and polyene antifungal agents in the fungal cell?
Both act on ergosterol in the fungal membrane: azoles inhibit ergosterol synthesis (14-alpha-demethylase); polyenes (e.g. amphotericin B) bind ergosterol directly, forming membrane pores.
Distinguish yeasts from moulds (filamentous fungi), and define a dimorphic fungus.
Yeasts are single round/oval cells that reproduce by budding; moulds grow as filamentous hyphae forming a mycelium. Dimorphic fungi grow as mould in the environment (cooler temps) and yeast in tissue at 37 °C (e.g. Histoplasma).
What is the difference between septate and aseptate (coenocytic) hyphae, giving an example of each?
Septate hyphae have cross-walls dividing cells (e.g. Aspergillus); aseptate/coenocytic hyphae lack regular cross-walls and are multinucleate (e.g. Mucor/Rhizopus).
Which yeast causes oral/vaginal thrush and invasive candidiasis, and what predisposes to it?
Candida albicans; predisposed by antibiotic use, immunosuppression, diabetes, indwelling lines and prolonged ICU stay. It is a dimorphic yeast forming germ tubes.
Which fungus causes invasive pulmonary aspergillosis and in whom?
Aspergillus fumigatus; a septate mould causing invasive disease predominantly in neutropenic and immunocompromised patients, and aspergilloma in pre-existing lung cavities.
What are dermatophytes and which tissues do they infect?
Keratinophilic fungi (Trichophyton, Microsporum, Epidermophyton) that infect keratinised tissue—skin, hair and nails—causing tinea (ringworm) infections.
Which protozoan causes malaria, how is it transmitted, and which species is most lethal?
Plasmodium species transmitted by the bite of the female Anopheles mosquito; Plasmodium falciparum causes the most severe, potentially fatal disease (cerebral malaria).
Which protozoan causes amoebic dysentery and liver abscess, and how is it transmitted?
Entamoeba histolytica; transmitted faecal-orally via cysts in contaminated food/water, causing bloody diarrhoea and characteristic 'anchovy paste' liver abscesses.
Compare the transmission and clinical target of the roundworm Ascaris lumbricoides versus the tapeworm Taenia.
Ascaris (nematode): faecal-oral egg ingestion, larvae migrate through lungs then mature in the small intestine causing obstruction. Taenia (cestode): ingestion of undercooked pork/beef cysticerci, adult tapeworm resides in the gut; T. solium eggs can cause neurocysticercosis.
Name two clinically important ectoparasites and the conditions they cause.
Sarcoptes scabiei mite causes scabies (intensely itchy burrows); Pediculus/Pthirus lice cause pediculosis (head/body/pubic lice) and can act as vectors for typhus and relapsing fever.
What this deck covers
The Microbiology deck follows the MRCS Part A Microbiology syllabus — 9 chapters and 35 topics — so questions land on material that is genuinely examinable rather than trivia around it. That works out to roughly 5.8 cards per chapter.
Answers are written to be recallable, not just readable — averaging about 178 characters, which is long enough to carry the reasoning and short enough to say out loud.
A deck like this earns its keep on the second and third pass. Read the syllabus first so you know the shape of the subject, then use the cards to find the specific facts that have not stuck.
Microbiology flashcards FAQ
How many Microbiology flashcards are in this MRCS Part A deck?
52 cards. This page previews 24 of them, sampled evenly across the deck so you can judge the difficulty before installing anything.
Are these MRCS Part A flashcards free?
Yes. The preview here is free to read with no signup, and the full 52-card deck is free inside the Examius app.
What do the Microbiology cards cover?
They follow the MRCS Part A Microbiology syllabus — 9 chapters and 35 topics — so the questions track what is actually examinable.
How should I use these flashcards?
Read the syllabus first so you know the shape of the subject, then drill the deck. Examius schedules each card with spaced repetition, so cards you keep missing come back sooner and ones you know drift further apart.