SCHOOL OF NATUAL SCIENCES AND MATHEMATICS

Biology Department

Biology Laboratory Manual Level 1

 Note to Students
Students should read and study the exercises before coming to the
laboratory and should supply themselves with the necessary materials
including the prescribed text book, lecture notes, laboratory manual,
calculators, pens, and pencils. All students are required to wear
appropriate clothing to lab as outlined by the lab safety guidelines as
well as follow all safety precautions during laboratory exercises.

Biology is a hands-on laboratory study subject. Students are expected

to conduct all laboratory activities that may require the use of chemicals,
laboratory equipment, and other items which, if used incorrectly, can be
hazardous. Safety in the science classroom is the number one priority
for students, lecturers and technicians. To ensure a safe biology
classroom, a list of rules has been developed and will be provided to you
by the Biology Technician. These rules must be followed at all times.

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GENERAL SAFETY GUIDELINES

1. Conduct yourself in a responsible manner at all times in the laboratory.

2. Follow all written and verbal instructions carefully. If you do not understand a
direction or part of a procedure, ASK YOUR LECTURER/TECHNICIAN BEFORE
PROCEEDING WITH THE ACTIVITY.
3. No undergraduate student may work in the science classroom without the
presence of the lecturer/technician.
4. When first entering the laboratory, do not touch any equipment, chemicals, or
other materials in the laboratory area until you are instructed to do so.
5. Perform only those experiments authorized by your lecturer/technician. Carefully
follow all instructions, both written and oral. Unauthorized experiments are not
allowed.
6. Do not eat, drink or chew in the laboratory. Do not use laboratory glassware as
containers for food or beverages.
7. Be prepared for your work in the laboratory. Read all procedures thoroughly
before entering the laboratory. Never fool around in the laboratory. Horseplay,
practical jokes, and pranks are dangerous and prohibited.
8. Always work in a well-ventilated area.
9. Observe good housekeeping practices. Work areas should be kept clean and tidy
at all times.
10. Be alert and proceed with caution at all times in the laboratory. Notify the
lecturer/technician immediately of any unsafe condition you observe.
11. Dispose of all chemical waste properly. Never mix chemicals in sink drains.
Sinks are to be used only for water. Check with your lecturer/technician for disposal
of chemicals and solutions.
12. Labels and equipment instructions must be read carefully before use. Setup and
use the equipment as directed by your lecturer/technician.
13. Keep hands away from face, eyes, mouth, and body while using chemicals or lab
equipment. Wash your hands with soap and water after performing all experiments.
14. Experiments must be personally monitored at all times. Do not wander around
the room, distract other students, startle other students or interfere with the
laboratory experiments of others.
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15. Know the locations and operating procedures of all safety equipment including:
first aid kit(s), and fire extinguisher. Know where the fire alarm and the
EMERGENCY EXITS are located.
16. Know what to do if there is a fire drill during a laboratory period; containers must
be closed, and any electrical equipment turned off.

CLOTHING
17. Any time chemicals, heat, or glassware are used, students will wear safety
goggles. NO EXCEPTIONS TO THIS RULE!
18. Contact lenses may not be worn in the laboratory.
19. Dress properly during a laboratory activity. Long hair, dangling jewellery, and
loose or baggy clothing are a hazard in the laboratory. Long hair must be tied back,
and dangling jewellery and baggy clothing must be secured. Shoes must completely
cover the foot. No sandals allowed on lab days.
20. A lab coat should be worn during laboratory experiments.

ACCIDENTS AND INJURIES

21. Report any accident (spill, breakage, etc.) or injury (cut, burn, etc.) to the
lecturer/technician immediately, no matter how trivial it seems.
22. If you or your lab partner is hurt, get the lecturer/technician's attention. Do not
panic.
23. If a chemical should splash in your eye(s) or on your skin, immediately flush with
running water for at least 20 minutes. Immediately get the lecturer/technician's
attention.

HANDLING CHEMICALS/SAMPLES
24. All chemicals/samples in the laboratory are to be considered dangerous. Avoid
handling chemicals/samples with fingers. Do not taste, or smell any
chemicals/samples.
25. Check the label on all chemical/sample bottles twice before removing any of the
contents. Take only as much chemical/sample as you need.

26. Never return unused chemicals/samples to their original container.

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27. Never remove chemicals/samples or other materials from the laboratory area.

HANDLING GLASSWARE AND EQUIPMENT

28. Never handle broken glass with your bare hands. Use a brush and dustpan to
clean up broken glass. Place broken glass in the designated glass disposal
container.
29. Examine glassware before each use. Never use chipped, cracked, or dirty
glassware.
30. If you do not understand how to use a piece of equipment, ASK THE
LECTURER/TECHNICIAN FOR HELP!
31. Do not immerse hot glassware in cold water. The glassware may shatter.

HEATING SUBSTANCES
32. Do not operate a hot plate by yourself. Take care that hair, clothing, and hands
are a safe distance from the hot plate at all times. Use of hot plate is only allowed in
the presence of the lecturer/technician.
33. Heated glassware remains very hot for a long time. They should be set aside in
a designated place to cool, and picked up with caution. Use tongs or heat protective
gloves if necessary.
34. Never look into a container that is being heated.
35. Do not place hot apparatus directly on the laboratory desk. Always use an
insulated pad. Allow plenty of time for hot apparatus to cool before touching it.

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How to prepare a practical report
Scientific reports of research experiments are usually written up using the following
headings:-
1) Abstract
2) Introduction
3) Materials and Methods
4) Results
5) Discussion
6) Conclusion
7) References

Following is a brief description of the individual sections.

(1) Abstract
This should provide a concise overview of the report. It should briefly describe the
experiment and its aims, and then explain what was discovered and the relevance of
the findings. The abstract should include 5 sentences that addresses the following:
(i) aim, (ii) what was done (iii) major findings and (iv) implications of the results

(2) Introduction
Give a brief history of what is already known from other research of relevance to the
topic/title. State briefly and specifically what you wish to determine. A minimum of
three paragraphs is expected and they should include (i) opening paragraph, (ii)
literature review and (iii) purpose of the experiment

(3) Materials and Methods

Describe what was done and how, e.g. the experiment design, experimental
materials used, what was measured and the methods used, and details of the
methods of statistical assessment of the results i.e. if any. The detail should be
sufficient to enable another scientist to repeat the experiment and duplicate the
experimental conditions.

(4) Results
Summarise all data arising from the experiment. Results are usually presented in the
form of well labelled drawings, tables and figures. On describing the results more
attention should be applied on important (usually statistically significant) findings.
Presenting raw data should be avoided. The fewer and simpler the Tables and
Figures the better: avoid presenting the same data in both Tables and Figures.
Ensure the reader has sufficient information to verify the main conclusions. Avoid
discussing the results under this section. Restrict yourself to simply highlighting
important trends and differences in your data.

(5) Discussion
Discuss your results in relation to current knowledge of the subject (from previous
similar studies). It is important also to relate the results to the objective of your
experiment – was the aim achieved satisfactorily? If not, explain why. Discuss any
‘aberrant’ results, deviations from the expected, trends and significant differences.

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(6) Conclusion
Highlight the main findings. Avoid saying things that have not been presented under
RESULTS and adequately discussed under DISCUSSION section. Discuss practical
implications of the study and suggest how knowledge of the topic might be further
advanced by further research.

(7) References
NB. Any statement that you make, that is not your own idea, should be followed by a
cited reference, or other acknowledgement. The rule is you cite in text and only
included citations that appear in text in your reference list. You must indicate how the
reader can gain access to the source of information you have referred to. Citations in
a scientific report should be acknowledged in an accepted (and consistent) manner,
e.g.

Scott, M.L., Nesheim, M.C. and Young, R.J. (1976). Nutrition of the Chicken, 2nd
edition, M.L. Scott and Associates, Ithaca, New York.

NRC (1977). Nutrient Requirements of Domestic Animals. No. 1. Nutrient

Requirements of Poultry, 7th revised edition. The National Research Council,
National Academy of Sciences, USA.

Wyatt, R.D. Tung, H.T., Donaldson, W.E. and Hamilton, P.B. (1973). A new
description of riboflavin deficiency syndrome in chickens. Poultry Science, 52, 237-
242.

RIRDC (1999). ‘Five year plan. Rural Industries Research and Development
Corporation
http://www.rirdc.gov.au/pub/chick5yr.htm (website accessed July, 2001).

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Practical 1: Microscopy

In this practical, you will:

• Calibrate an eyepiece graticule and use it to do measurements.
• Make a temporary preparation of some onion epidermis cells
• Stain the cells so that you can see structures within them
• Set up a light microscope and use it to make observations and measurements
• Make a drawings of labelled onion cells

Materials

• Light microscope with light source

• Onion
• Tweezers
• Scapels
• Iodine solution/Methyl Blue
• Droppers
• Filter paper
• Safety googles
• Clean Slides
• Cover slips
• Microscope slide
• Ocular micrometer
• Eye piece graticule

Part A: Calibrating the eyepiece graticule

1) If it does not already have one, insert a graticule into the eyepiece of the
microscope by unscrewing the top lens, resting the graticule on the rim halfway
down.
2) Place a stage micrometer slide on the stage of the microscope. Note the smallest
division on the stage micrometer.
3) Using the low-power objective, focus the microscope on the stage micrometer.
Rotate the eyepiece and move the slide to superimpose the scales of the eyepiece
graticule and that of the stage micrometer.
4) Showing all the necessary steps, calculate the calibration factor at (i) low power [5
marks], (ii) medium power [5 marks] and high power [5 marks].
5) You have now calibrated the eyepiece graticule and you can use it to measure
cells in the exercises below.

Part B: Observing onion cells and measurements

Background
Preparing onion cell slides is a convenient way to observe simple plant cells under
the light microscope. In this activity you are going to use your practical skills to
prepare, observe and do measurements on onion cells under the light microscope.

Method
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1) Using tweezers carefully peel off a thin layer of epidermis from the onion.
2) Lay the membrane on the microscope slide in a single flat layer.
3) Place a very small drop of iodine solution/Methyl blue on the membrane.
4) Carefully lower a cover slip on top of the membrane (make sure there are no air
bubbles).
5) Place the slide on the stage of the microscope.
6) Make sure the lowest objective lens is over the specimen.
6) Carefully use the course focusing knob to lower the objective lens to just above
the slide.
7) Look through the eye piece and carefully use the fine focusing knob to focus the
image.
8) On a clean printing paper draw three adjacent cells that you are seeing through
the microscope [2 marks].
9) Carefully change the objective lens so that you are looking through a high
powered one you will be able to see cells at a higher magnification and other
organelles. Add more details on the three adjacent cells that you drew under bullet 9
and label your drawings [3]. [Remember to use a sharp pencil]
10) Use the calibrated eyepiece graticule to measure the width and length of one of
the epidermal cells that you have drawn [5 marks].

[25 marks]