How do I know if my submission is
appropriate for the Critical Thinking
Question Bank (CTQB)?
Samantha Elliott
St. Mary’s College of Maryland
CTQB Resource Session
ASMCUE 2012
Bloom’s Taxonomy
Knowledge
Comprehension
Application
Analysis
Synthesis
Evaluation
Lower-order
cognitive skills
Higher-order
cognitive skills
• To reach higher-order thinking, students must be
able to complete lower order skills
The Blooming Biology Tool
• Crowe et al. (2008) CBE-Life Sci Ed vol 7: 368381
• 5 Bloom’s levels appropriate for multiple
choice questions
– All except synthesis
• Appropriate for CTQB: Application, Analysis or
Evaluation
Lower-order cognitive skills questions
(Crowe et al. 2008)
• Knowledge
– Recall of information
– No significant distractors
• Comprehension
– Understanding of concept or terms
– Includes significant distractors to test student
misconceptions
Higher-order cognitive skills questions
(Crowe et al. 2008)
• Application
– Prediction of most likely outcome
– New situation or perturbation of system
• Analysis
– Data interpretation and selection of best
conclusion
• Evaluation
– Assessment of information relative to support of
an argument
Caveats/Suggestions
• Bloom’s level can be modified depending on
how the information is presented in the
classroom.
• Not a perfect system
• Use author comments to help reviewers
understand why you think the question
addresses higher-order cognitive skills.
Time to practice!
Which of the following is the correct order of
the steps of a Gram stain?
1(A). Safranin  Iodine  Alcohol  Crystal violet
2(B). Crystal violet  Iodine  Alcohol  Safranin
3(C). Iodine  Crystal violet  Alcohol  Safranin
4(D). Alcohol  Safranin  Iodine  Crystal violet
5 (E). Crystal violet  Iodine  Safranin  Alcohol
Bloom’s level: Knowledge
Author’s comments: This question tests the ability of the
student to recall the steps of a Gram stain. There is no
higher order thinking other than memorization. Depending
upon the specific reagents used in the classroom, instructors
can substitute more specific terms for “Iodine” and “Alcohol.”
Scientists engineer a Gram-positive bacterium to express a
polysaccharide-rich outer capsule. What effect would this
have on a Gram stain of this engineered organism?
1 (A). It would still stain as a Gram-positive bacterium.
2 (B). It would stain as a Gram-negative bacterium.
3 (C). It would become a Gram-indeterminate
bacterium.
4 (D). It would become a Gram-variable bacterium.
5 (E). Cannot tell from the information provided.
Bloom’s level: Application
Author’s comments: This is a classic perturbation of the
system, testing the ability of students to understand what
happens to a Gram stain when you add in a polysaccharide
capsule. Note that application questions can require either
lower- or higher-order cognitive skills. For purposes of CTQB,
we accept any multiple choice question at application level or
higher according to Bloom’s taxonomy.
As your final project in Microbiology lab, you are tasked with identifying a single,
unknown organism. One of your friends asks you to check over her work to see if it
makes sense. She hypothesizes that she has identified a gut-associated bacterium
based upon the results in the table below. Based upon these results, choose the best
answer in regards to your friend’s hypothesis.
Gram stain
negative
Cell
Motility? Spores?
morphology
short rod
yes
no
Lactose
fermentation
Oxygen
requirements
positive
facultative
anaerobe
1 (A). Her hypothesis is correct. It’s definitely a gut-associated organism.
2 (B). Her hypothesis may be correct. She should run a coagulase test to be sure.
3 (C). Her hypothesis may be correct. She should grow the organism on MacConkey
agar to be sure.
4 (D). Her hypothesis is incorrect. It’s definitely a soil-associated organism.
5 (E). Her hypothesis is incorrect. She should run more tests to identify the
organism.
Bloom’s level: Evaluation
Author’s notes: This question not only requires data
interpretation, but the use of this information to support a
specific hypothesis, making it an evaluative item. Enteric
organisms can grow in the presence of bile salts, which are
present in MacConkey agar. Because this organism is already
identified as a Gram-negative bacterium, MacConkey agar is
an appropriate choice because it selects for growth of only
Gram-negative bacteria.
MacConkey agar would be
inappropriate for a Gram-positive enteric organism, such as
Enterococcus species. A bile esculin test would be more
appropriate for those organisms.
Which step of the Gram stain dissolves lipids
within the cell wall?
A. Crystal violet
B. Iodine
C. Alcohol
D. Safranin
E. Water
Bloom’s level: Comprehension
Author’s comments: This question tests the ability of students
to comprehend the purpose of different steps in the Gram
stain. While it is still lower-level cognition, more thought
than simple memorization is required. Depending upon the
specific reagents used in the classroom, instructors can
substitute more specific terms for “Iodine” and “Alcohol.”
Your microbiology class is characterizing a single unknown bacterium. Each member of
the class performs three independent Gram stain replicates on the culture, and adds
their results to the table below. Which of the following is the best conclusion about
your aggregate data?
Name
Age of cultures
Cell Morphology
Gram stain results
John
10-12 hours
Rod, in chains
Gram positive, Gram positive, Gram positive
Sue
12-14 hours
Rod, in chains
Gram positive, Gram positive, Gram positive
12 hours
Rod, in chains
Gram positive, Gram negative, Gram positive
Liz
12-24 hours
Rod, in chains
Gram positive, Gram negative, Gram negative
Steve
24-36 hours
Rod, in chains
Gram negative, Gram negative, Gram negative
Mary
1 (A). Fresh staining solutions should be made and the Gram staining performed again.
2 (B). The unknown bacterium is Gram positive. Changes in cell wall structure cause
older cultures to stain differently.
3 (C). The unknown bacterium is Gram negative. Newer cultures have incomplete cell
walls which cause them to stain differently.
4 (D). The unknown bacterium is Gram indeterminate.
5 (E). Students should practice their Gram staining technique on known bacteria
before trying this experiment again.
Bloom’s level: Analysis
Author’s comments: This question requires students to
interpret data and select the best outcome. The primary
concept tested here is that age of culture plays a huge role in
the outcome of a Gram stain. Newer cultures are better
indicators of Gram type than older cultures.
Your turn!