Microbiology flashcards for NEET PG
79 cards. Read the question, answer in your head, then check. For spaced repetition, study the deck in the app.
What this deck is for
These 79 cards pick out single facts in Microbiology that the exam keeps returning to: Bacterial toxins, Culture media, Virology, Parasitology, Immunology and serology, Bacteriology and more. Make a one-line identity card for each organism: shape and stain, defining test, toxin, disease and drug. Cards are a starting set, not full coverage of the subject; the study guide lists the full map.
Where students slip in Microbiology: Confusing similar organisms with different tests. Read the Microbiology study guide.
1 · Bacterial toxins
Mechanism of cholera toxin vs diphtheria toxin?
Show the answer
Cholera: ADP-ribosylates Gs, raising cAMP. Diphtheria: ADP-ribosylates EF-2, stopping protein synthesis.
Memory hook: Both ADP-ribosylate, but different targets.
2 · Culture media
Selective medium for Neisseria gonorrhoeae?
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Modified Thayer–Martin agar.
Memory hook: Chocolate agar plus antibiotics.
3 · Virology
Inclusion body of rabies, and where is it found?
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Negri body: in neurons, notably hippocampus and cerebellar Purkinje cells.
Memory hook: Direct fluorescent antibody is also used.
4 · Parasitology
Vector of kala-azar in India?
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The sandfly, Phlebotomus argentipes.
Memory hook: LD bodies in macrophages.
5 · Immunology and serology
Non-treponemal vs treponemal tests for syphilis?
Show the answer
Non-treponemal: VDRL, RPR. Treponemal: FTA-ABS, TPHA.
Memory hook: VDRL for follow-up; TPHA for confirmation.
6 · Bacteriology
Which organism is optochin sensitive?
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Streptococcus pneumoniae.
Memory hook: Bile soluble too.
7 · Bacteriology
Which streptococcus is bacitracin sensitive?
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Group A Streptococcus (S. pyogenes).
Memory hook: Group B is bacitracin resistant and CAMP positive.
8 · Bacteriology
Which organism causes whooping cough and what medium grows it?
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Bordetella pertussis; Bordet–Gengou or Regan–Lowe medium.
Memory hook: Whoop: paroxysmal cough.
9 · Virology
How are hepatitis A and E transmitted?
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By the faecal–oral route.
Memory hook: B, C and D are blood-borne.
10 · Parasitology
Which malaria species cause relapses?
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Plasmodium vivax and P. ovale, through dormant hypnozoites in the liver.
Memory hook: Primaquine clears hypnozoites.
11 · General microbiology and sterilisation
Which spore indicator is used to monitor an autoclave?
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Geobacillus stearothermophilus spores.
Memory hook: Steam heat-resistant spores.
12 · General microbiology and sterilisation
Which spore indicator checks hot air oven sterilisation?
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Bacillus atrophaeus (subtilis var. niger) spores.
Memory hook: Dry heat, dry-loving Bacillus.
13 · General microbiology and sterilisation
What are the standard autoclave conditions for routine sterilisation?
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121 degrees C at 15 psi for 15 minutes.
Memory hook: 121, 15, 15.
14 · General microbiology and sterilisation
What are the standard hot air oven conditions?
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160 degrees C for 2 hours.
Memory hook: Dry heat needs more time.
15 · General microbiology and sterilisation
Which method sterilises heat-labile items such as plastics and catheters at low temperature?
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Ethylene oxide gas (also plasma sterilisation).
Memory hook: Cold gas sterilant.
16 · General microbiology and sterilisation
Which method is used to sterilise heat-labile liquids like serum and antibiotic solutions?
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Filtration through membrane filters (for example 0.22 micron).
Memory hook: Filters remove, not kill.
17 · General microbiology and sterilisation
What is the gold standard method of sterilisation for most surgical instruments?
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Moist heat by autoclaving (steam under pressure).
Memory hook: Steam kills spores.
18 · General microbiology and sterilisation
Which bacterial structure is mainly responsible for resistance to heat and disinfectants?
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The endospore, with its dipicolinic acid and calcium-rich core.
Memory hook: Spore equals survivor.
19 · General microbiology and sterilisation
Which stain is used for diagnosing tuberculosis in sputum, and what is its principle?
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Ziehl-Neelsen: carbol fuchsin retained by mycolic acid after acid decolourisation.
Memory hook: Acid-fast means mycolic acid.
20 · Immunology
Which immunoglobulin crosses the placenta?
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IgG.
Memory hook: G for Going across.
21 · Immunology
Which immunoglobulin is the first to appear in a primary response and is the largest?
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IgM, a pentamer.
Memory hook: M for Macro and first.
22 · Immunology
Which immunoglobulin is the main one in secretions such as milk and saliva?
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Secretory IgA (dimer with secretory component).
Memory hook: A for Airways and milk.
23 · Immunology
Which immunoglobulin is bound to mast cells in type I hypersensitivity?
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IgE.
Memory hook: E for Early allergy.
24 · Immunology
Which complement pathway is activated by antigen-antibody complexes?
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The classical pathway, starting with C1q.
Memory hook: Classical begins at C1.
25 · Immunology
Deficiency of which complement components predisposes to recurrent Neisseria infections?
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The terminal components C5 to C9 (membrane attack complex).
Memory hook: No MAC, Neisseria attacks.
26 · Immunology
Which MHC class presents antigen to CD8 T cells?
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MHC class I.
Memory hook: 8 x 1 = 8.
27 · Immunology
Which MHC class presents antigen to CD4 T cells?
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MHC class II.
Memory hook: 4 x 2 = 8.
28 · Immunology
Which type of hypersensitivity is tuberculin skin test reaction, and which cell mediates it?
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Type IV (delayed), mediated by sensitised T cells.
Memory hook: Delayed, T cell, 48 to 72 hours.
29 · Immunology
Which type of hypersensitivity is serum sickness and Arthus reaction?
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Type III, immune complex mediated.
Memory hook: Three: complexes.
30 · Bacteriology
Which organism shows tumbling motility at 25 degrees C and grows in the cold?
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Listeria monocytogenes.
Memory hook: Cold enrichment.
31 · Bacteriology
Which organism shows a medusa head colony and bamboo-stick (square-ended) bacilli?
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Bacillus anthracis.
Memory hook: Anthrax, medusa head.
32 · Bacteriology
Which medium is used for Corynebacterium diphtheriae and which stain shows its granules?
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Loeffler serum slope or tellurite medium; Albert stain shows metachromatic granules.
Memory hook: Albert shows the beads.
33 · Bacteriology
What is the Elek test used for?
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To demonstrate toxigenicity of C. diphtheriae by in vitro immunodiffusion.
Memory hook: Elek checks the toxin.
34 · Bacteriology
Which organism causes pseudomembranous colitis after antibiotics, and what toxins does it produce?
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Clostridioides difficile; toxins A and B.
Memory hook: Treat with oral vancomycin or fidaxomicin.
35 · Bacteriology
Which toxin of Clostridium perfringens causes gas gangrene?
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Alpha toxin, a lecithinase (phospholipase C).
Memory hook: Nagler reaction demonstrates it.
36 · Bacteriology
What is the typical appearance of Neisseria meningitidis on Gram stain?
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Gram-negative kidney-shaped diplococci, often intracellular within neutrophils.
Memory hook: Coffee-bean pairs.
37 · Bacteriology
Which test differentiates Staphylococcus aureus from other staphylococci?
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Coagulase test (positive in S. aureus).
Memory hook: Aureus is coagulase positive.
38 · Bacteriology
Which coagulase-negative coccus is the second commonest cause of urinary tract infection in young sexually active women, and how is it identified?
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Staphylococcus saprophyticus; novobiocin resistant.
Memory hook: Saprophyticus, honeymoon cystitis.
39 · Bacteriology
Which medium is used to grow Mycobacterium tuberculosis?
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Lowenstein-Jensen medium, with colonies appearing in 4 to 8 weeks.
Memory hook: Slow, rough, buff colonies.
40 · Bacteriology
Which organism needs X and V factors for growth?
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Haemophilus influenzae.
Memory hook: Satellitism around Staph aureus.
41 · Bacteriology
Which organism causes Weil disease and how is it transmitted?
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Leptospira interrogans; contact with water contaminated by rat urine.
Memory hook: Jaundice, renal failure, haemorrhage.
42 · Bacteriology
Which spirochaete causes Lyme disease and what is the vector?
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Borrelia burgdorferi; Ixodes tick.
Memory hook: Erythema migrans.
43 · Bacteriology
Which serological test is used for enteric fever and which antigens does it detect?
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Widal test: antibodies to O (somatic) and H (flagellar) antigens of Salmonella Typhi.
Memory hook: Blood culture is best in week 1.
44 · Virology
Which hepatitis B marker indicates active viral replication and high infectivity?
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HBeAg (with HBV DNA).
Memory hook: e for expressing.
45 · Virology
Which hepatitis B marker is the only positive one in the window period?
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IgM anti-HBc.
Memory hook: Core antibody fills the gap.
46 · Virology
Which hepatitis B marker alone indicates vaccination immunity?
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Anti-HBs without anti-HBc.
Memory hook: Vaccine has only surface antigen.
47 · Virology
Which virus causes infectious mononucleosis and which test is classic?
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Epstein-Barr virus; Paul-Bunnell heterophile antibody test (monospot).
Memory hook: Atypical lymphocytes.
48 · Virology
Which virus family has a segmented genome allowing antigenic shift?
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Orthomyxoviridae, the influenza viruses.
Memory hook: Shift is reassortment.
49 · Virology
What is the difference between antigenic drift and shift?
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Drift is point mutation causing minor change; shift is genome reassortment causing major change and pandemics.
Memory hook: Shift is sudden and big.
50 · Virology
Which virus produces owl-eye intranuclear inclusions?
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Cytomegalovirus.
Memory hook: Owl-eye is CMV.
51 · Virology
Which virus causes hand, foot and mouth disease?
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Coxsackievirus A16 (and enterovirus 71).
Memory hook: Picornavirus.
52 · Virology
Which HIV enzyme is the target of nucleoside reverse transcriptase inhibitors, and what is the gene for it?
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Reverse transcriptase, encoded by the pol gene.
Memory hook: pol: RT, protease, integrase.
53 · Virology
Which HIV gene encodes gp120 and gp41?
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The env gene.
Memory hook: env is envelope.
54 · Virology
Which test is used for early diagnosis of HIV in a newborn of an infected mother?
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HIV DNA or RNA PCR, as maternal antibody persists up to 18 months.
Memory hook: Not ELISA in infants.
55 · Mycology
Which fungus shows narrow-based budding yeasts with a thick capsule on India ink?
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Cryptococcus neoformans.
Memory hook: India ink halo.
56 · Mycology
Which fungus has acute-angle septate hyphae and is seen in neutropenic patients?
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Aspergillus species.
Memory hook: Acute 45 degree branching.
57 · Mycology
Which fungus has broad, non-septate hyphae with right-angle branching and causes rhino-orbital-cerebral disease?
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Mucorales (Rhizopus, Mucor), causing mucormycosis.
Memory hook: Diabetic ketoacidosis.
58 · Mycology
Which dimorphic fungus is linked to bird and bat droppings and appears as small intracellular yeasts in macrophages?
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Histoplasma capsulatum.
Memory hook: Caves, bats.
59 · Mycology
Which medium is used to grow most fungi?
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Sabouraud dextrose agar.
Memory hook: SDA.
60 · Mycology
Which dermatophyte genus infects hair, skin and nails?
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Trichophyton (Microsporum infects hair and skin; Epidermophyton skin and nails).
Memory hook: Trichophyton hits all three.
61 · Mycology
Which fungus causes pneumonia in AIDS with cysts seen on silver stain?
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Pneumocystis jirovecii; treated with cotrimoxazole.
Memory hook: CD4 below 200.
62 · Parasitology
Which malaria species causes the most severe disease and cerebral malaria?
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Plasmodium falciparum.
Memory hook: Falciparum is the killer.
63 · Parasitology
Which stage of Plasmodium is infective to humans?
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Sporozoite, injected by the female Anopheles mosquito.
Memory hook: Sporo goes in.
64 · Parasitology
Which stage of Plasmodium is infective to the mosquito?
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Gametocyte.
Memory hook: Gamete is taken up.
65 · Parasitology
Which protozoan causes amoebic liver abscess and what does the abscess pus look like?
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Entamoeba histolytica; anchovy sauce pus.
Memory hook: Metronidazole treats.
66 · Parasitology
Which helminth causes iron deficiency anaemia through intestinal blood loss?
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Hookworm (Ancylostoma duodenale and Necator americanus).
Memory hook: Skin penetration by larvae.
67 · Parasitology
Which tapeworm larva causes neurocysticercosis?
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Taenia solium cysticercus, acquired by ingesting eggs.
Memory hook: Eggs, not pork, cause it.
68 · Parasitology
Which parasite causes hydatid cyst and who is the definitive host?
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Echinococcus granulosus; the dog is the definitive host.
Memory hook: Avoid aspiration without albendazole cover.
69 · Parasitology
Which filarial worm causes lymphatic filariasis in India?
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Wuchereria bancrofti, vector Culex mosquito, with nocturnal periodicity.
Memory hook: Blood film at night.
70 · Parasitology
Which protozoan infects the cat as definitive host and is dangerous in pregnancy?
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Toxoplasma gondii.
Memory hook: Chorioretinitis, calcification.
71 · Parasitology
Which stage of Giardia is infective, and which diagnostic stage is seen in stool?
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The cyst is infective; trophozoites and cysts are seen in stool.
Memory hook: Falling leaf motility.
72 · Clinical microbiology and hospital infection control
Which are the commonest organisms causing catheter-associated urinary tract infection in hospitals?
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E. coli is commonest; Klebsiella, Pseudomonas and Enterococcus follow.
Memory hook: Gut flora travel up the catheter.
73 · Clinical microbiology and hospital infection control
What is the most important single measure to prevent hospital-acquired infection?
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Hand hygiene.
Memory hook: Clean hands save lives.
74 · Clinical microbiology and hospital infection control
Which colour bag is used for disposal of infectious soft waste such as dressings under Indian biomedical waste rules?
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Yellow bag.
Memory hook: Yellow for infectious.
75 · Clinical microbiology and hospital infection control
Which colour container is used for sharps such as needles under Indian biomedical waste rules?
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White (translucent) puncture-proof container.
Memory hook: Sharps in white.
76 · Clinical microbiology and hospital infection control
Which organism is the classic cause of ventilator-associated pneumonia with blue-green pus?
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Pseudomonas aeruginosa (pyocyanin pigment).
Memory hook: Oxidase positive.
77 · Clinical microbiology and hospital infection control
What defines MRSA and which gene is responsible?
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Methicillin-resistant S. aureus; the mecA gene encoding altered PBP2a.
Memory hook: Treat with vancomycin or linezolid.
78 · Clinical microbiology and hospital infection control
Which enzyme confers resistance to carbapenems in Enterobacterales?
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Carbapenemase (for example NDM-1, KPC, OXA-48).
Memory hook: NDM stands for New Delhi.
79 · Clinical microbiology and hospital infection control
What is a minimum inhibitory concentration (MIC)?
Show the answer
The lowest concentration of an antibiotic that inhibits visible growth of an organism.
Memory hook: Inhibits, not kills.
Common questions
How many Microbiology flashcards are there?
79 cards across 10 topics. The deck grows as we add material.
Which topics are in the Microbiology deck?
Bacterial toxins, Culture media, Virology, Parasitology, Immunology and serology, Bacteriology, General microbiology and sterilisation, Immunology, Mycology, Clinical microbiology and hospital infection control.
Is the Microbiology deck free?
Microbiology opens with a paid term. The free plan includes the Anatomy, Physiology and Biochemistry decks.
How do spaced-repetition cards work?
You rate each card Again, Hard, Good or Easy. Cards you find hard return soon and cards you know return later, so your time goes where you forget.
What is the memory hook on a card?
79 of these cards carry a one-line hook: a short cue that helps the answer stick. It is optional and appears after you reveal the answer.
How many Microbiology cards should I do a day?
Ten to twenty minutes a day is plenty. A few due cards every day beat a long session once a week.
Can I flip through the cards on this page?
You can read each question and reveal its answer here. For scheduling, ratings and progress, study the deck in the app.
Are the Microbiology cards reviewed by faculty?
Not yet. They are original and still awaiting independent review, so confirm anything important in a standard textbook.