JAMB/WAEC Biology Objective Test: 25 Questions on Microbial Culture Techniques

In microbiology, culturing techniques are used to grow and study microorganisms under controlled conditions.
A culture consists of microorganisms growing on a nutrient medium, which may be solid or liquid.
To achieve reliable results, processes such as sterilization, inoculation, incubation, and observation must be properly carried out.

The following questions are designed in JAMB and WAEC standard to test not only your understanding but also your ability to think logically about microbial culturing processes.

Biology Objective Test: 25 Questions on Microbial Culture Techniques

1. 1. A student observed growth in the control plate. This suggests that
      A. the medium was too rich
      B. aseptic technique failed
      C. incubation was too long
      D. agar was insufficient

1. 1. The main function of agar in culture media is to
      A. provide nutrients
      B. act as a solidifying agent
      C. sterilize the medium
      D. enhance reproduction

1. 1. Different culture media are required because microorganisms
      A. differ in size
      B. have varying nutritional needs
      C. reproduce differently
      D. have different shapes

1. 1. A Petri dish is opened slightly during inoculation to
      A. allow oxygen in
      B. speed up growth
      C. reduce contamination
      D. cool the medium

1. 1. Talking while preparing a culture may lead to
      A. increased growth
      B. contamination
      C. sterilization
      D. evaporation

1. 1. The purpose of a control experiment is to
      A. increase growth rate
      B. confirm validity of results
      C. sterilize the medium
      D. reduce errors

1. 1. Failure to sterilize agar properly will result in
      A. no growth
      B. unwanted growth
      C. delayed growth
      D. nutrient loss

1. 1. The step that follows inoculation is
      A. sterilization
      B. incubation
      C. observation
      D. labeling

1. 1. Sealing Petri dishes with tape helps to
      A. increase heat
      B. prevent contamination
      C. improve visibility
      D. enhance growth

1. 1. Which is NOT a contamination source?
      A. Air
      B. Water
      C. Sterile instruments
      D. Hands

1. 1. Growth in a control plate indicates
      A. good incubation
      B. contamination
      C. nutrient excess
      D. low temperature

1. 1. Incubation is done in warm conditions to
      A. dry the medium
      B. support microbial growth
      C. reduce oxygen
      D. prevent contamination

1. 1. Sneezing near a culture leads to
      A. sterilization
      B. contamination
      C. faster growth
      D. evaporation

1. 1. Aseptic technique refers to
      A. fast growth
      B. contamination prevention
      C. chemical use
      D. identification

1. 1. A nutrient-poor medium will cause
      A. excessive growth
      B. poor growth
      C. contamination
      D. rapid division

1. 1. Which is correctly matched?
      A. Agar – energy source
      B. Yeast extract – nutrients
      C. Petri dish – sterilizer
      D. Loop – incubator

1. 1. Using different water samples helps to
      A. sterilize medium
      B. compare microbes
      C. reduce contamination
      D. increase nutrients

1. 1. Identical growth in all plates suggests
      A. identical organisms
      B. contamination occurred
      C. incubation failed
      D. no nutrients

1. 1. The inoculating loop is used to
      A. sterilize
      B. transfer microbes
      C. observe
      D. incubate

1. 1. Excessive heat during incubation will
      A. promote growth
      B. kill microorganisms
      C. increase nutrients
      D. reduce contamination

1. 1. Sick individuals should avoid culturing because they
      A. reduce nutrients
      B. introduce microbes
      C. affect agar
      D. slow incubation

1. 1. Colony characteristics help in
      A. sterilization
      B. identification
      C. incubation
      D. preparation

1. 1. Sterilizing instruments helps to
      A. improve speed
      B. prevent contamination
      C. increase nutrients
      D. reduce heat

1. 1. Tissue culture involves
      A. bacteria only
      B. fungi only
      C. multicellular cells
      D. non-living matter

1. Failure to label Petri dishes leads to
   A. faster growth
   B. confusion of results
   C. contamination
   D. sterilization

Answers

1. B
2. B
3. B
4. C
5. B
6. B
7. B
8. B
9. B
10. C
11. B
12. B
13. B
14. B
15. B
16. B
17. B
18. B
19. B
20. B
21. B
22. B
23. B
24. C
25. B