Botany 101 Lab Manual
Tacoma Community CollegeBiology Laboratory: Safety, Procedures, Emergencies
1. No open food or drink is permitted in the lab at any time, whether a lab is in progress or not. No eating, drinking, chewing of gum or tobacco is permitted. Never taste anything at all while in the lab rooms.
2. Know the locations of the eye wash and shower stations, fire alarm, fire extinguisher, first aid kit, and emergency exits.
3. Safety instructions are given at the beginning of each lab period. Always arrive on time so that you know what you are supposed to do and are informed of any specific safety concerns or safety equipment associated with the day’s lab activity.
4. Wear any required personal protective equipment (lab coat, apron, goggles, etc).
5. Stash book bags safely so that they won’t trip people.
6. Report all illnesses, injuries, breakages, or spills to your laboratory instructor immediately.
7. Clean broken glass (glass that is not contaminated with any chemical reagents, blood, or bacteria) can be swept up using the dust pan and placed in the broken glass container. If the glass is contaminated in any way, keep the area clear to prevent tripping or laceration hazards, and consult your instructor for proper disposal guidance. A broken glass flow-chart is available in the lab to help you decide what to do.
8. Notify your instructor if any of the equipment is faulty.
9. Clean up your entire work area before leaving. Put away all equipment and supplies in their original places. Disinfect your work surface if the lab activity involved any infectious materials.
10. Use the appropriate waste containers provided for any infectious or hazardous materials used in lab.
11. Safety information about hazardous chemicals used in the lab activities can be found in the Material Safety Data Sheets (MSDS), located in the Right-to-Know Binder in the safety station. We (faculty and students) should be fully aware of the properties of the chemicals we are using. Please use the MSDSs. If you cannot find the MSDS for the reagent you are using in lab, inform your instructor. They are also relatively easy to find online. A keyword example is “Sodium Chloride MSDS.”
12. Use caution with the lab chairs. Because they are on casters, the can roll away when you are standing at your workstation. Make sure your chair is where you expect it to be before sitting down. Do not use your chair as a means of moving from one part of the lab to the other.
13. Wash your hands before leaving the lab room.
Laboratory 1: Pea Lab - Principles of the Scientific Method
Adapted by permission from Steve Brumbaugh from the Green River Biology Lab Manual
Exercise: Applying the Scientific Method
The work required for this lab spans about four weeks depending on a number of factors. Your instructor will explain the methods of storage for your experimental set-ups, and how to arrange for the use of the rooms and greenhouse to do your work.
Pre-lab Assignment
Before coming to lab carefully read the sections of your textbook regarding the scientific method and the pages of this exercise then answer the pre-lab questions.
Goals of this Lab Exercise
· To understand the mechanisms used in the scientific method
· Design an experiment and carry out the steps of a scientific experiment
· To work cooperatively in establishing a protocol for a scientific experiment
Introduction
In its simplest form, an experiment involves a check or control group compared with an experimental or test group. The control is held under constant conditions while the test group is exposed to the affects of various factors, one at a time. Any changes that occur in the test group, but not in the control group, are assumed to be the result of the condition that is changed. Each treatment, including the control, should be replicated, and the replicate organisms should be carefully distributed so that no individuals being treated will be favored more than others. In the activity that follows, you will design your own original experiment.
Materials (per group of four students)
20 Little Marvel pea seeds and 2 flower pots / Atomizer containing gibberellic acid solutionGrowth medium (vermiculite in greenhouse) / Atomizer of de-ionized water
Procedure
Each team should decide on its organization, discuss the problem/hypothesis, and plan the experiment. Gather the materials needed and begin the activity. Prepare your seeds planting by following the following method.
1. Seed Preparation - Place 20 pea seeds in a beaker and cover them with tap water so that the water level is about 2 cm above the level of the pea seeds. Label the beaker with team identification and date. Place it in a dark cupboard in the biology lab and let the pea seeds soak overnight (i.e. 12-24 hours). The soaked seeds should now be planted as directed below.
2. After the seeds have soaked overnight take them to the greenhouse. Prepare 4 flowerpots by adding moistened soil to each. The containers should be about 3/4 full. In each pot, place 6 soaked seeds. Cover the seeds with another ½ inch of moistened soil. Label each pot with team identification and date and keep them in the greenhouse. Keep the medium moist, but not soggy wet.
3. When the seedlings are 2-3 cm high measure their height in millimeters. This is done by measuring the distance from the growth medium surface to the tip of the shoot apex. Measure each seedling and record your data. These lengths are the initial measurements. You will now apply your experimental treatment to your experimental group. First you need to decide what your experimental treatment will be! You can use one of the following suggestions, or come up with your own. If you use your own, please check your ideas with your instructor.
a. Spray plants with gibberrelic acid, a growth hormone
b. Add a few fertilizer pellets
c. Grow your plants under blue or red light
d. Grow your plants in the shade
e. “pinch” your plants when they are about 4cm high (this means plucking off the uppermost leaves)
f. Grow your plants outside the greenhouse
4. On each day of class, measure & calculate the average number of leaves per plant, the average internode length, and the average height per treatment. Record your data on the data table in your in-lab report sheet.
Figure 1 Plant Anatomy This drawing is to be used to guide the measurement of the inter-node length.
Report Sheet Name .
Pea Lab Exercise Group Names .
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.
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Table1: Average internode length, number of leaves per plant, and height for the pea plant experiment
Date / Ave. internode length (cm) / Ave. # of leaves per plant / Average height (cm) / ObservationsExperimental Group
Control Group
Experimental Group
Control Group
Experimental Group
Control Group
Experimental Group
Control Group
Experimental Group
Control Group
Experimental Group
Control Group
1. Prepare a graph of the average daily heights for both the experimental and control groups. Properly title and label your graph (Appendix A). Graph both sets of data on the same graph by using different colors and a key. Attach this graph to your lab. In the space below, explain the results and trends seen in your graph:
2. Prepare a graph of the average internode lengths for both the experimental and control groups. Properly title and label your graph (Appendix A). Graph both sets of data on the same graph by using different colors and a key. Attach this graph to your lab. In the space below, explain the results and trends seen in your graph:
3. Prepare a graph of the average number of leaves for both the experimental and control groups. Properly title and label your graph (Appendix A). Graph both sets of data on the same graph by using different colors and a key. Attach this graph to your lab. In the space below, explain the results and trends seen in your graph:
4. What correlation(s) did you observe between number of leaves, internode length, and plant height?
5. List at least two observations of similarities and/or differences in the general growth of the experimental and control plants other than the observations recorded in question 4 above.
6. List at least three possible sources of error that may have influenced the data you collected.
7. Suggest 3 ways to provide more valid data or show other pertinent results. Be specific!!!
8. Did you confirm your hypothesis? YES / NO (Circle One)
Pre-Lab Report Sheet
Pea Lab Exercise
Name______
Note: / Answer the following six questions before coming to lab, but after having read the previous pages of this handout!1. Write a hypothesis using the "If .... Then" format for this experiment.
2. What is the independent variable for your pea experiment?
3. What is the dependent variable(s) for your pea experiment?
4. Name at least three controlled variables in the pea experiment?
5. Give a brief explanation of your experimental design:
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Laboratory 2: Microscopy
Parts of the Swift M5 Microscope
Microscopy
Purpose
This lab is designed to give the student a basic understanding of microscopy, and introduce proper techniques for using a compound, light microscope. The primary objectives of this lab are for the student to:
- Understand the importance of microscopy in viewing individual cells.
- Identify the parts of a compound light microscope and their function.
- Demonstrate and practice proper techniques for use and care of a compound light microscope.
- Make a wet mount slide preparation.
Background
The basic unit of life and the smallest hierarchical level that can be considered alive is the cell. All living things, simple or complex, are made of cells and much has been learned through their analysis. The human eye is able to resolve objects less than a millimeter (1.0 mm) in size, but not much smaller than that. Although there are some cells that can be observed with the naked eye (human egg cell, squid giant axons, etc.) most cells are too small to be viewed without assistance. Today, in order to visualize small specimens such as individual cells, a light microscope is most commonly used. The first light microscopes were invented in the 17th century AD by Anton Von Leeuwenhoek, Von Leeuwenhoek was able to achieve a magnification of approximately 270X. The invention of the light microscope opened up a new world for biologists to study, and the field of Microbiology was born. Today’s modern light microscopes are capable of magnifying images over 1000X, enough to clearly see even some of the smallest cells.
Exercises:
Part A: Using the Swift M5 Microscope and Viewing a Letter “e”
1. Carrying the Microscope: Always use two hands, one of which should support the base while the other holds the arm of the microscope. Microscopes contain delicate optical structures that could be damaged through impact. Thus, be very careful and gentle when setting down the scope and moving it.
2. Setting up: The eyepieces (oculars), condenser lens, and light source should be clean and dust-free. You may want to wipe these surfaces with a lens-grade Kim Wipe prior to using the microscope.
3. You will now prepare a wet mount of a letter “e.” Follow the steps below. You will use this slide to become oriented with using the microscope and to learn how to measure the field of view.
a. Obtain a clean glass slide and a letter “e.”
b. Place the letter “e” in the center of the slide, and, using the water dropper bottle, place a drop of water over the letter “e”.
c. Place a cover slip over the drop of water and letter “e”.
4. Ensure that the lowest power (red) objective is pointing at the stage before placing your slide on the stage.
5. Place your slide on the stage. Look at the stage, not through the eyepieces. Use the mechanical stage controls to position your slide such that the letter is directly over the condenser lens.
6. Move the iris diaphragm lever to the left and use the condenser lens knob to raise the condenser lens to the highest position possible. Find the knob that raises and lowers the condenser lens under the left-hand side of the stage. You should not loosen the condenser lens with the pins that are used to hold it under the stage.
7. Turn on the microscope and use the rheostat wheel on the front of the stage to adjust the light so that it is not too bright or dim – go for what is comfortable for your eyes.
8. Look through the eyepieces- don’t worry about focusing yet. What do you see? Two circles, one blurry circle, or one clear circle? Do not worry about whether you can see the slide clearly – all you should be focusing on right now is the circle – if you see two circles, you need to push your eyepieces together a bit. If you see a blurry circle, you need to widen them. When you find the right distance for your eyes, look at where the dial is between the eyepieces. You can select the best distance for you using that number whenever you need to use your microscope for the rest of the quarter.
9. Finally, set the ocular lens focus. Bring the “e” into focus using the coarse focus knob and then the fine focus knob. Look through the right eyepiece with your right eye – close your left eye. Use the fine focus to make the image as sharp as possible. Now look through the left eyepiece with your left eye and close your right eye. If the image is blurry in any way, sharpen it by rotating the left eyepiece clockwise or counterclockwise.
10. With each slide, ALWAYS start with the scanning (4X, red) objective. With the 4X objective, you may start with the coarse focus knob and then use the fine focus knob to sharpen the image. Look at your “e.” Draw what you see in on the In-Lab Report Sheet #1.
11. Next, look at the slide with the low power (10X, yellow) objective. The objectives should be parfocal, which means that you should only need to use the fine focus knob. Note how the objectives increase in length with magnification power. The coarse focus moves the stage up and down, and you may run the slide into the objective if you use coarse focus with the longer objectives. Draw what you see in the report pages. Draw what you see in on the In-Lab Report Sheet #1.