Unit 1: Introduction to microbiology and microbial evolution - Practice Quiz

1 Who is credited with first observing microorganisms using a simple microscope?

2 The term "cell" was first coined by which scientist?

3 Which scientist disproved the theory of spontaneous generation using swan-necked flasks?

4 Who developed a set of postulates to establish that a specific microbe causes a specific disease?

5 Who discovered penicillin, the first widely used antibiotic?

6 Who is regarded as the father of antiseptic surgery for introducing sterile techniques?

7 Which of the following is a type of microorganism?

8 The study of viruses is known as which branch of microbiology?

9 The branch of microbiology that studies fungi is called:

10 Microbial life is estimated to have existed on Earth for approximately how long?

11 Microorganisms that thrive in extreme environments are collectively called:

12 Layered rock structures formed by ancient microbial communities are known as:

13 Which group of organisms lacks a membrane-bound nucleus?

14 Which of the following microorganisms is a eukaryote?

15 The three-domain system of classification was proposed by which scientist?

16 Which of the following is NOT one of the three domains of life?

17 The two-word naming system used to name organisms is called:

18 Which molecule is most commonly used to determine microbial phylogenetic relationships?

19 A diagram that shows the evolutionary relationships among organisms is called a:

20 A close relationship where both organisms benefit is called:

21 A student is asked why Antonie van Leeuwenhoek is credited as the first to observe microorganisms rather than earlier scientists who proposed 'invisible living seeds' of disease. What is the best justification?

22 Pasteur's swan-neck flask experiment is considered decisive against spontaneous generation primarily because it demonstrated that:

23 Koch's postulates are applied to establish a causal link between a microbe and a disease. Which situation would MOST directly violate the ability to fulfill these postulates?

24 Sergei Winogradsky and Martinus Beijerinck advanced general microbiology largely by introducing the concept and technique of:

25 The discovery of chemolithotrophy by Winogradsky was significant for general microbiology because it revealed that some microbes can:

26 Carl Woese's use of small subunit rRNA sequences transformed modern microbiology chiefly by allowing scientists to:

27 Metagenomics represents a major advance in the modern era because it enables researchers to:

28 Stromatolites are considered important evidence for the antiquity of microbial life because they:

29 The discovery of thriving microbial communities at deep-sea hydrothermal vents challenged earlier assumptions primarily by showing that life can:

30 Microorganisms found deep within Earth's crust, in extremely nutrient-poor rock, are significant because they demonstrate that microbial life can:

31 Which observation best supports the claim that prokaryotic metabolic diversity exceeds that of eukaryotes?

32 Extremophiles such as halophiles and thermophiles are frequently members of which domain, reflecting that domain's adaptation to harsh conditions?

33 A researcher notes that fungi, protists, and some algae are all microbial yet eukaryotic. What feature best distinguishes them collectively from bacterial microbes?

34 In the hierarchical classification system, which sequence correctly proceeds from the broadest to the most specific rank?

35 Two bacterial strains show 65% DNA-DNA hybridization. Using the conventional 70% threshold, how should they most appropriately be classified?

36 Why has phenotypic classification alone proven insufficient for reliably identifying many bacteria?

37 Why is the 16S rRNA gene particularly well suited as a molecular chronometer for reconstructing microbial phylogeny?

38 Horizontal gene transfer complicates the interpretation of microbial phylogenetic trees because it can:

39 In a rooted phylogenetic tree, the node representing the last common ancestor of two taxa is best interpreted as:

40 In a relationship where one microbe benefits while the other is unaffected, such as a bacterium living on the skin surface without harming or helping the host, the interaction is best described as:

41 Pasteur's swan-neck flask experiment is often credited with disproving spontaneous generation. Which specific feature of the experimental design made his conclusion logically stronger than earlier attempts by Redi and Needham?

42 Koch's postulates were revolutionary but have well-known limitations. Which scenario represents a valid pathogen that would still fail a strict application of the original postulates?

43 Carl Woese used the small-subunit rRNA gene as a molecular chronometer. Which combination of properties makes 16S/18S rRNA especially suited for deep phylogenetic inference?

44 Two bacterial strains share 98.5% 16S rRNA identity but only 45% DNA–DNA hybridization (DDH). Applying standard prokaryotic species criteria, what is the most defensible conclusion?

45 The concept of 'the great plate count anomaly' refers to which observation, and what does it imply for estimates of microbial diversity?

46 Horizontal gene transfer (HGT) complicates tree-based phylogeny. Which analytical strategy best mitigates HGT artifacts when reconstructing deep organismal relationships?

47 Stromatolites and putative microfossils suggest early microbial life. Which line of geochemical evidence most specifically supports biological (rather than abiotic) carbon fixation in Archean rocks?

48 Metagenomics enables the study of uncultured communities. What is the principal advantage of shotgun metagenomic sequencing over 16S rRNA amplicon sequencing for functional inference?

49 In a syntrophic association between a fatty-acid-oxidizing bacterium and a methanogen, why is the partnership thermodynamically obligate for the bacterium?

50 Average Nucleotide Identity (ANI) has largely replaced DNA–DNA hybridization for species delineation. What ANI value approximately corresponds to the traditional 70% DDH species boundary?

51 Beijerinck and Winogradsky pioneered enrichment culture and the concept of general microbiology. What key principle underlies the enrichment culture technique?

52 Long-branch attraction (LBA) is a systematic error in phylogenetics. Under what circumstance is LBA most likely to produce an incorrect tree?

53 Quorum sensing allows population-density-dependent gene regulation. Why is a diffusible autoinducer coupled with a threshold response advantageous for behaviors like bioluminescence or virulence?

54 Winogradsky's discovery of chemolithotrophy fundamentally changed microbial physiology. Which statement best captures its conceptual significance?

55 A polyphasic taxonomic approach is recommended for describing new prokaryotic taxa. What does 'polyphasic' specifically require?

56 The deep subsurface biosphere and extremophiles expand the known limits of life. Which environmental parameter combination poses the greatest simultaneous challenge, requiring polyextremophilic adaptation?

57 Rarefaction curves are used to assess sampling completeness in diversity studies. What does a rarefaction curve that has NOT reached a plateau indicate?

58 The three-domain system distinguishes Archaea from Bacteria despite both being prokaryotic. Which molecular feature is a genuine archaeal hallmark distinguishing them from bacteria?

59 Distinguishing amensalism from competition can be subtle. Which scenario best exemplifies amensalism rather than competition?

60 When using a molecular clock to estimate divergence times, which assumption, if violated, most seriously undermines the age estimates?