Name: ________________________
Biology Research Project #1: An Investigation into the Characteristics of Life
Research Question:
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Sketch out a “Model” (like a mind map) to explain the phenomenon:
A
What specific hypotheses will you test in the lab?
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Analysis
DNA Station:
Describe what you observed:
Explain how this gives evidence of life:
How might your results be otherwise interpreted?
Microscopic Examination Station:
Describe what you observed:
Explain how this gives evidence of life:
How might your results be otherwise interpreted?
Metabolic Activity Station:
Describe what you observed:
Explain how this gives evidence of life:
How might your results be otherwise interpreted?
Enzymatic Activity Station:
Describe what you observed:
Explain how this gives evidence of life:
How might your results be otherwise interpreted?
Conclusions:
Write out a discussion on this lab, be sure to address the following:
 Was the research question answered?
 Discuss possible sources of error
 Design and map out a follow up experiment to better determine if something is alive.
 How would you revise the model?
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Is it Alive? Microscopic Examination
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Obtain 2 small petri dishes, just the top or bottom for each will do.
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Fill both about half full with warm (around 37 degrees Celsius) de-chlorinated tap water, to one add a
scoopula of growth media and mix this in.
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Now add 1 scoopula of the test substance to each petri dish, and mix in.
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The plate with the growth media needs to set about 20 minutes, so while you wait make a wet mount of
the contents from the first petri dish. View first without stain, then a second time with a biological stain.
Try several different stains to determine which gives the best contrast and resolution. Suggested stains
include: iodine, methylene blue, safranin, and crystal violet.
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Sketch below, showing any evidence for cellular structure at 400X:
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Repeat the wet mounts for the second petri dish, and sketch below:
Is it Alive? Detecting Metabolic Activity- Gases
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Set up a warm water bath, as close to 37ºC as possible. To do this, put a 600 mL beaker about one third
full of tap water on a hot plate set on high. Use a thermometer, have 1 member of your group keep a
close eye on the temperature.
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Obtain a sample of the test material, about 5 grams will do.
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Set up 4 test tubes with contents as follows:
o
o
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Test tube 1: 5 mL water (with no chlorine)
Test tube 2: 5 mL water + .5 grams glucose
Test tube 3: 5 mL water + .5 grams sucrose
Test tube 4: 5 mL water + .5 grams starch
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Add 1 gram of test material to each tube, and mix into solution
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Make sure the water bath is not over 40ºC, now set the 4 test tubes down in the bath
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Place a small balloon over each test tube, if balloons are not available, cover all 4 test tubes with
aluminum foil.
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It make take 20 minutes, or as few as 10 minutes for any gases to be produced, so go back to your desks
and work on the lab analysis.
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After you think gases have been produced, test each tube by quickly removing the cover, and
immediately lowering a burning splint into the tube.
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Note which tubes produced gas, and what gas or gases you think were produced:
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Is it Alive? Detecting Enzymatic Activity

Obtain a sample of the test material, about 5 grams will do.
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Set up 4 test tubes with contents as follows:
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Test tube 1: 5 mL water (with no chlorine)
Test tube 2: 5 mL hydrogen peroxide (H2O2)
Test tube 3: 4 mL hydrogen peroxide + 1 mL 1 molar HCl
Test tube 4: 4 mL water + 1 mL 1 molar NaOH
Test tube 5: 5 mL hydrogen peroxide
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Add 1 gram of test material to test tubes 1, 2,3,and 4, then mix into solution
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Place a small piece of aluminum foil over test tube # 2 as it is reacting in order to trap some of the gas
produced, then, before it all leaks out, test the gas with a burning splint
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Save the contents of test tube # 2 for later
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For test tube #5: Use a funnel and filter paper, filter out the test substance from test tube #2 above.
Scrape this off the paper, then add it to test tube #5 which has fresh hydrogen peroxide.
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Note which tubes produced gas, and what gas or gases you think were produced:
Contents
Test tube
#1
Test tube
#2
Test tube
#3
Test tube
#4
Test tube
#5
Gas produced?
Other observations
Is it Alive? DNA Purification
Procedure
1.
In a 400 mL beaker add .75g sodium chloride, .25g EDTA, and .75g SDS detergent. Dilute to a volume of 75 mL with tap
water and stir to dissolve. Note: When cells are added to this solution, the salt attaches to the free ends of the DNA and
keeps them from combining with other molecules as the cells are disrupted. The EDTA causes the other cell material to
clump together and be removed by precipitation. The SDS detergent is a surfactant that will help break down the cell
membranes.
2.
Add to an empty 150 mL beaker 3 grams of your sample (which may contain cells with DNA). Then add the solution from
step one to mix with the sample. Incubate this beaker in a hot water bath set at 60º C for 5 minutes. A hot water bath is a
600 mL beaker about 1/3 full of tap water set on a hot plate, float the smaller beaker in this, be sure to monitor the
temperature to keep it as close to 60º C as possible, exceeding this temperature will denature the DNA.
3.
Cool the small beaker containing the sample homogenate to 10º C in a ice-water bath to cause precipitation.
4.
Pour the cooled homogenate into a blender and blend the sample to a pulpy mass (over blending creates excess foam). If no
blender is available, grind the homogenate in a mortar and pestle to release the DNA from the sample.
5.
Pour the blended (or ground up) homogenate into a cleaned 400 mL beaker and further cool in an ice-water bath for 5
minutes. This will allow the precipitation of cellular components and some of the foam to settle. Filter the homogenate
through about 4 layers of cheese cloth using a funnel and Erlenmeyer flask.
6.
Transfer 10 mL of the filtrate into a clean test tube, save the excess in case you need to try the following steps again.
7.
DNA precipitation: Obtain 20 mL of ice-cold 95% ethanol directly from the freezer or cooler using a small 50 mL beaker.
Do not allow anything to warm up from now on! Trickle approximately 20 mL of cold ethanol down the sides of the test
tube containing the onion filtrate. You should see a white mucous-like layer forming at the boundary between the alcohol
and filtrate. This is the DNA!
Observe and record the appearance of the solution and
any precipitates that form:
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