Division of Science and Technology
School of Science
S1253 Microbiology (SS12BMI)

November, 1990

TIME ALLOWED The examination paper has been divided into two (2) sections. Section I is worth 120 marks and should be answered in the main answer book. Section ll is worth 40 marks and should be answered in the supplementary answer book provided. Remember to write your name on the answer b ooks before attempting any questions. Attempt all questions. allocate your time wisely in relation to the number of marks assigned for each question and time available.
This section is to be answered in the main answer book.

Question 1 - Answer one (1) of the following questions.

(a) Microbes are morphologically, metabolically and physiologically diverse and are ubiquitous in nature. Provide evidence for this statement. Use labelled diagrams wherever appropriate.


(b) Compare, contrast and discuss the cell walls and cell membranes of eubacteria, eucaryotes and archaeobacteria. provide labelled diagrams wherever appropriate.


(c) Discuss, citing examples, the taxonomic organisation of the Gram positive bacteria in Bergey's Mannual of Systematic Bacteriology.

Question 2 - Write notes on and/or draw schematic diagrams for any six (6) of the following:

(a) Arrangement and structure of bacterial flagella.

(b) Pasteurization

(c) Sporulating bacteria

(d) Chlamydia

(e) Endotoxins and exotoxins

(f) Azotobacter and Rhizobium

(g) The typical bacterial growth curve.

(h) Fungi

(I) Protozoa

Question 3 - Answer all of the following multiple choice questions. Write only the correct alphabet letter against the question number in your answer book.

  1. Cells with a relatively complex morphology that have a true membrane-delimited nucleus are called:

    a. procaryotes

    b. eucaryotes

    c. urcaryotes

    d. nocaryotes

  2. Acid-fast organisms such as Mycobacterium tuberculosis resist decolorization by an acid-alcohol wash because of the high concentration of _____ in their cell walls.

    a. proteins

    b. carbohydrates

    c. lipids

    d. peptidoglycan

  3. When smears of microorganisms are stained the smear is heat fixed in order to:

    a. kill the organism

    b. attach the organism firmly to the slide

    c. both a and b

    d. neither a or b

  4. The lipopolysaccharide (LPS) that is found in the other membrane of gram-negative bacteria is also known as:

    a. exotoxin

    b. teichoic acid

    c. murein

    d. endotoxin

  5. Chemotaxis implies that bacteria:

    a. move towards an attractant

    b. move away from a repellent

    c. both a and b

    d. neither a nor b

  6. The term used to describe bacteria that are shaped like curved rods is:

    a. coccus

    b. bacillus

    c vibrio

    d. coccobacillus

  7. Bacteria are called _______ if they can metabolise only methane, methanol, carbon monoxide, formic acid and a few related one-carbon molecules.

    a. methylotrophs

    b. carbotrophs

    c. monotrophic

    d. autotrophic

  8. Mannitol salt agar (MSA) only allows the growth of halophiles. Among the halophiles, mannitol fermenters release acid that turns the pH indicator yellow; mannitol nonfermenters leave the medium red. Onto MSA you inoculate a halophilic mannitol fermenter and a nonhalophilic mannitol nonfermenter. Here the medium acts as a _____ medium.

    a. selective

    b. differential

    c. both a and b

    d. neither a nor b

  9. Organisms that do not require oxygen for growth but grow better in its presence are called:

    a. facultative anaerobes

    b. microaerophiles

    c. aerotolerant

    d. anoxygenic

  10. Organisms that are damaged by the normal atmospheric levels of oxygen (20%) but require oxygen at levels of 2-10% for growth are called:

    a. facultative anaerobes

    b. microaerophiles

    c. aerotolerant

    d. anoxygenic

  11. If you formed antibodies against O antigen of certain bacterial strains, where would the antibody be found to bind to the bacterial cell?

    a. nucleoid

    b. ribosome

    c. capsule

    d. outer membrane of cell wall

  12. Which of the following components of various pathogenic microbes does not play a role in the attachment of pathogens to surfaces of the body?

    a. fimbrae

    b. flagella

    c. capsule

    d. glycocalax

    e. spike

  13. The ______ are obligate intracellular parasites.

    a. Bacillus

    b. Chlamydia

    c. Clostridium

    d. Mycobacterium

    e. Mycoplasma

  14. Which of the following constitutes the natural reservoir of Salmonella typhi?

    a. rats

    b. mosquitoes

    c. chickens

    d. dogs

    e. humans

  15. For which of the following would penicillin therapy prove completely infective?

    a. Streptococcal sore throat

    b. gonorrhea

    c. gangrene (Clostridium perfringens)

    d. Mycoplasma pneumoniae

    e. Staphylococcal inpetigo

  16. Toxic shock syndrome (TSS) is caused by:

    a. rare strains of Streptococcus pyogenes

    b. toxigenic strains of Straphylococcus aureus

    c. Clostridium botulinum

    d. Escherichia coli

    e. Clostridium perfringens

  17. A major distinguishing characteristic of archeobacterial phospholipids is the presence of:

    a. ester linkages

    b. ether linkages

    c. hydrophobic fatty acids

    d. polar head groups

    e. sterols

  18. Members of the genus Arthrobacter are:

    a. irregular branched rods in exponential growth.

    b. coccoid during stationary phase

    c. both a and b

    d. neither a nor b

  19. The facultatively anaerobic gram-negative rods consist of the:

    a. Enterobacteriaceae

    b. Vibrionaceae

    c. Pasteurellaceae

    d. all of the above

  20. Yersinia is best known as the causative agent of:

    a. bubonic plague

    b. whooping cough

    c. cholera


Author: Dr Bharat Patel <>
HTML'd by Troy Baalham
[Created: 01 Apr 1996]
[Modified: 20 May 1996]