T HE U NIVERSITY O F
B RITISH C OLUMBIA
M ICROBIOLOGY 202 PRACTICE
EXAM -STYLE Q UESTIONS – ACTERIALPATHOGENESIS
Recommended time for completion: 1 hour, 15 minutes
NAME :________________________ STUDENT #__________________
FAILURE TO FOLLOW INSTRUCTIONS WILL DELAY THE GRADING OF YOUR EXAM
1. All students must adhere to the Faculty of Science rules governing formal examinations (see next page).
2. This exam has 33 questions.-choice questions have one answer. Other multiple-
choice questions will require you to select two or more answers – this is indicated in the question stem
(all must be correct in order to receive the point). This exam has 5 double-sided pages including the
3. Record all multiple choice responses IN DARK PENCIL on the computer answer sheet — NOT on
the question paper. Rough work may be done on the question paper, but nothing written on it will be
4. Make sure to fill in the bubbles for your name (Family name FIRST, Given name LAST ) and your 8
digit student number IN PENCIL. Other student information is NOT required. IN INK, sign the
question paper and the answer sheet in the spaNOT be marked if thisam paper will
is not done correctly.
5. Students MUST record their answers onto their answer shNOt during the time allowed for the exam.
writing will be permitted after the time allowed for the exam has expired.NO appeals will be considered.
6. The question paperMUST be returned with the answer sheet. An answer sheet without question paper
will NOT be graded. In this regard, students areSTRONGLY CAUTIONED to guard against theft of
their question paper by other students. NO appeal relating to loss of a question paper by theft will be
7. The invigilators willNOT answer any clarifStudents must interprethe exam.
and answer each question on their own.
8.NOTE: There will be questions that require one answy bubbles to fill. You will be told how man
in for each question. Actual exam questions will have a maximum of 5 answers to choose from and you will not see
the phrase “For this question, pick as many answers as necessary to correctly answer the question”. 2
Faculty of Science Rules Governing Formal Examinations
#1. Each candidate must be prepared to produce, upon request, a Library/AMS card for identification.
#2. Candidates are not permitted to ask questions of the invigilators, except in cases of supposed errors or
ambiguities in examination questions.
#3. No candidate shall be permitted to enter the examination room after the expiration of on -half hour from
the scheduled starting time, or to leave during the first half hour of the examination.
#4. Candidates suspected of any of the following, or similar, dishonest practices shall be immediately
dismissed from the examination and shall be liable to disciplinary action:
• Having at the place of writing any books, papers or memoranda, calculators, computers, aduio or
video cassette players or other memory aid devices, other than those authorized by the examiners.
• Speaking or communicating with other candidates.
• Purposely exposing written papers to the view of other candidates. The plea of accident or
forgetfulness shall not be received.
#5. Candidates must not destroy or mutilate any examination material; must hand in all examination papers;
and must not take any examination material from the examination room without permission of the
READ EACH QUESTION STEM CAREFULLY. THERE ARE NO PARTIAL MARKS
FOR QUESTIONS REQUIRING MORE THAN ONE ANSWER. You will not see the phrase
“For this question, pick as many answers as necessary to correctly answer the question” in the
actual exam, but they are a very good way to test your knowledge of the material which is why
they are used here. Actual exam questions will have a maximum of 5 answers to choose from.
1. The skin is an effective barrier to pathogens in all but which of the following ways?
(a) Leukocytes are closely associated with the skin.
(b) The surface cells continually fall off making it difficult for pathogens to gain a foothold.
(c) The pH of the skin is normally acidic.
(d) The salt content of the skin is high.
(e) Sebum and sweat contain substances that inhibit the growth of most pathogens.
2. A pathogen is a bacterium which:
(a) will always cause harm to a normal host.
(b) is capable of harming a normal host.
(c) contains a large number of virulence determinants.
(d) is capable of spreading through the blood or lymph.
(e) colonizes individuals weakened by other reasons.
3. What type(s) of bacteria would you expect to find as the normal flora of the lower respiratory
(a) The same organisms as the upper respiratory tract.
(b) Escherichia coli.
(c) Gram negative and Gram positive cocci.
(d) It would vary - it is partially dependent on where the person lives.
(e) There should be no bacteria present.
(f) Streptococcus pneumoniae.
4. Koch’s postulates are an attempt at determining whether a particular microorganism is
responsible for a particular disease. Which two of the following statements describe limitations
that may be observed by a pathologist trying to apply Koch’s postulates?
(a) All pathogens can be grown in pure culture.
(b) A pathogen that causes a disease in a human will cause the same disease in an
(c) Normal flora bacteria that are present in healthy individuals may be the cause of disease
in the ill individual.
(d) Some bacteria that are pathogenic to most individuals may establish themselves as part of
the normal flora in other individuals.
(e) A bacterial pathogen that is resistant to an antibiotic may be the causative agent of the
5. Which two of the following statements are do not accurately describe how the normal flora
provide protection from infection by pathogenic microorganisms?
(a) They produce antimicrobial compounds called defensins.
(b) They out-compete newcomers.
(c) They make the chemical environment unsuitable for non-resident bacteria.
(d) They produce lysozyme.
(e) They stimulate the immune system to produce antibodies that may cross-react with
6. Microbial antagonism means that:
(a) good microbes establish themselves in the host and prevent invasion by pathogenic
(b) a bacteria that establishes within a host benefits from the association, but the host is
(c) good microbes are replaced by invading pathogenic microbes.
(d) pathogenic bacterial growth is encouraged by the presence of established host organisms.
(e) the host is predisposed to disease due to the microbes they harbour.
7. For this question, pick as many answers as necessary to correctly answer the question.
Which of the following is an example of a nosocomial infection?
(a) A child that develops flesh-eating disease while at school.
(b) A burn patient develops a Pseudomonas infection while in hydrotherapy in the hospital.
(c) A person steps on a nail in the garden and develops tetanus.
(d) A patient develops a secondary infection after completing antibiotic therapy at home.
(e) A man develops a staphylococcal skin infection after visiting his hospitalized wife.
8. Which two of the following statements are TRUE of biofilms?
(a) Biofilms are enmeshed in an extracellular polymeric substance (EPS).
(b) Biofilms form spontaneously without prior stimulus to the bacteria.
(c) In a biofilm composed of a single species of bacteria, all bacteria in the biofilm would
have the same sensitivity to an antibiotic.
(d) All biofilms are always composed of a single species of bacteria.
(e) In a biofilm, the bacteria in the interior of the biofilm are often metabolically inactive and
therefore more resistant to antibiotic.
9. Bacteria are grown on an agar plate in the presence of a gradient of an antibiotic. The lowest
concentration of antibiotic that results in no growth of the bacteria is the:
(a) 50% inhibitory dose.
(b) infectious dose.
(c) lethal dose to kill 50% of the bacteria.
(d) minimal lethal concentration (MLC).
(e) minimal inhibitory concentration (MIC). 5
10. For this question, pick as many answers as necessary to correctly answer the question.
The use of antibiotics in animal feed leads to antibiotic resistant bacteria because:
(a) bacteria from other animals replace those killed by the antibiotics.
(b) the antibiotics kill susceptible bacteria, but the few that are naturally resistant live and
reproduce, and their progeny repopulate the host animal.
(c) the few surviving bacteria that are affected by the antibiotics had developed resistance to
the antibiotics, which they pass on to their progeny.
(d) the antibiotics act as a mutagen and cause new mutations to occur in the surviving
bacteria, which results in resistance to antibiotics.
(e) the presence of the antibiotic promotes the growth of these bacteria.
11. Vaccination with tetanus toxoid induces immunity by which of the following mechanisms?
(a) it neutralizes the effects of the Clostridium tetani toxin
(b) it prevents Clostridium tetani from entering the blood stream
(c) it induces complement-mediated lysis of Clostridium tetani
(d) it inhibits production of tetanus toxin by Clostridium tetani
(e) it prevents the invasions of cells by Clostridium tetani
12. Epidemiologists use specific words to describe the presence of infectious diseases in society.
A disease that is present at a relatively constant, albeit low, level in a population is termed a/an
13. What is an epidemic that is widely distributed called?
(c) common-source epidemic
14. When a tick transfers Lyme disease from a deer to a human, the tick is considered the
_____________ in the chain o