The Effects of Snails and Elodea in Water
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This lab is used to test the effect the respiration rates in plants in animals and how it affects the level of carbon dioxide present in the water. Oxygen and carbon dioxide are gases that are vital to all organisms, whether it is given or released through that organism. Both plants and animals use oxygen and carbon dioxide for cellular respiration, giving off carbon dioxide as a waste product. This lab is an example of cellular respiration in both plants and animals. The change in the carbon dioxide levels will be measured and visible due to an indicator called Bromthymal Blue (BTB). This indicator will change the color of the water based on the carbon dioxide levels within the test tube. When there is little carbon in the mixture, the BTB indicator turns the water blue.
When there is a moderate amount of carbon dioxide, the water will be yellow. When there is a substantial amount of carbon dioxide in the water, it will be green. After the water is the ideal color yellow from being blown into by a straw, it is imperative that the seal remains closed to keep the carbon dioxide levels the same. Through performing this experiment, the close relationship between photosynthesis and cellular respiration will be discovered and better understood.
Test Tube 1: The elodea and snail in the test tube, placed in the light, will cause an intermediate amount of carbon dioxide, turning the water green. Test Tube 2: The elodea and snail in the test tube, placed in the dark, will produce a substantial amount of carbon dioxide, which will turn the water yellow Test Tube 3: The snail in the test tube, placed in the light, will produce a substantial amount of carbon dioxide, causing the water to be a shade of yellow Test Tube 4: The snail in the test tube, placed in the dark, will produce a large amount of carbon dioxide, which, in turn, will turn the water yellow Test Tube 5: The elodea in the test tube, placed in the light, will produce almost no carbon dioxide, which will turn the water to blue Test Tube 6: The elodea in the test tube, placed in the dark, will produce a large amount of carbon dioxide, causing the water to turn yellow Test Tube 7: With no organisms added to the mixture in the test tube, placing in the light will have no effect, and the water will remain yellow Test Tube 8: With no organisms added to the mixture in the test tube, placing in the dark will have no effect, and the water will remain yellow
– Large Test tube
– Distilled Water
– Pond Snails
– Test Tube Rack
– BTB Solution
– Light Stand
– Dark Closet
Please refer to attachments 1 and 2
Independent Variable: Contents of the test tube
Dependent Variable: Carbon dioxide levels
Control Group: Test tubes 7 and 8 that did not contain organisms Constants: Snail type, plant type, test tube type and size, water type and temperature, and BTB amounts
Analysis of Data:
Test tube 1 was placed in the light. It was blue at the top and yellow on the bottom. The elodea floated at the top and the snail had sunk to the bottom. Test tube 2 was placed in the dark. It was yellow all the way through with both the snail and the elodea at the top. Test tube 3 was placed in the light. It was yellow all the way through and the snail was at the bottom. Test tube 4 was placed in the dark. It was a bluish-green all the way through and the snail was at the top. Test tube 5 was placed in the light. It was blue all the way through and the elodea was sitting at the bottom. Test tube 6 was placed in the dark. It was yellow all the way through and the elodea was at the top. Test tube 7 was a control, meaning there were no added organisms, and was placed in the light. It was green. Test tube 8 was also a control, and was placed in the dark. It was yellow.
Test tube one contained both a snail and an elodea, and was placed in the light. It was hypothesized to turn green. Instead, the water was blue at the top and yellow at the bottom. It was blue at the top, where the elodea was, because the elodea was using the light and the carbon dioxide to perform photosynthesis. Due to the elodea photosynthesizing, there was little carbon dioxide in the top portion of the water. The bottom portion was yellow because the snail was not performing photosynthesis, because it is not a plant, and the snail was breathing out carbon dioxide. This factor is the cause of the bottom portion being yellow. Test tube two contained both a snail and an elodea and was placed in the dark. It was hypothesized that the water would be yellow. After a day, the water was yellow, matching the hypothesis. The water was yellow all the way through because it was placed in the dark where the elodea could not get light energy and carry out photosynthesis.
Test tube three contained a snail and was placed in the light. In the hypothesis, it was stated that the water would remain yellow. After a day, the water was yellow, proving the hypothesis. The water remained yellow because, even though it was placed in the light, a snail cannot photosynthesize and produce oxygen, only breathe out carbon dioxide. Test tube four contained a snail and was placed in the dark. It was hypothesized that the water would remain yellow after a day. When observed, the water was a blue-green all the way through. This is because the seal was more than likely not tight enough around the test tube, letting oxygen into the tube, which caused the color to change. Test tube five contained an elodea and was placed in the light.
It was hypothesized that the test tube would be blue in color after a day. Upon checking the test tubes, it was observed that the test tube was, in fact, blue. This is because the plant was in the test tube by itself, and placed in the light so the elodea could freely photosynthesize, which would eliminate a large portion of the carbon dioxide within the tube. Test tube six contained an elodea and was placed in the dark. It was hypothesized that, after a day, the test tube would be yellow in color. Upon observing, the hypothesis was proven correct because test tube six had remained yellow. This is because the elodea was placed in the dark where it could not receive light to photosynthesize and remove carbon dioxide from the air. Test tube seven was a control test tube, meaning it contained nothing other than the water BTB mixture.
It was placed in the light and hypothesized that the color would remain yellow. Upon observing, test tube seven was a shade of green. This is most likely an error in sealing the test tube, because there is no way a test tube can release carbon dioxide unless it is not sealed properly. Test tube eight was also a controlled test tube, and was placed in the dark. It was hypothesized that the color would remain yellow. After a day, the test tube was yellow. This is because the test tube contained no organisms, therefore no photosynthesis or cellular respiration could occur. In all, the experiment was widely effective in the purpose. This purpose being to create a better understanding of photosynthesis and cellular respiration, and the relation between the two, that was shown through a real-life situation.
Even though the overall experiment was a success, there were still sources of error. For example, the seal for the test tubes were not always tight enough, allowing oxygen to enter. This is an issue because the oxygen entering messes up the entire purpose of the lab. Another possible error is the carbon dioxide levels all being the same at the beginning of the lab. This was made easier by the BTB solution indicating the levels based off of color, but if all eight of the test tubes were not the same shade of yellow, the experiment cannot be effective. In a future study, the BTB should be poured into the solution before it is poured into the test tubes. This will eliminate the possibility of all the test tubes not being the same, which gets rid of a potentially harmful error.
Problem: What effects does gelatin have on different enzymes?
Background Info: Enzymes are essential for everyday life to be performed. Some enzymes used in daily life are meat tenderizer and laundry detergent. Meat tenderizer is made up mostly of an enzyme known as papain, which is from the papaya plant and is used in cooking to tenderize meat. Laundry detergent, on the other hand, is partially made of proteases, which are found in nature and are used to degrade proteins, but have been genetically engineered to put into the detergent. The protein used in this lab is gelatin, which is what gives Jell-O its “gel.” Gelatin is made of soluble animal protein, and when dissolved in water and cooled, it turns into a gel formation.
Hypothesis: The test tubes that contain the laundry detergent- gelatin mix will stay runny because of its water-like composition. The test tubes containing just gelatin and water will be similar to Jell-O because that’s what gelatin is. The test tubes containing meat tenderizer will gel, mostly because meat tenderizer is not designed to break meat down completely, but it’s also used to break it down some. It will have the same effect on gelatin.
•6 identical test tubes
•Test tube holder
•2 glass stirring rods
•30 mL of water
•6 parafilm wax sheets
•2.7 grams of gelatin
•1.2 mL of meat tenderizer
•1.2 mL of laundry detergent
•100 mL beaker
•Pen or pencil
•Masking tape for labeling
Methods/ Procedures: First, gather all of the materials and place on the lab table, making sure proper attire is retrieved, such as safety goggles and a latex apron before starting. Then, after gathering all that is needed, slowly bring 30 mL of water to a boil on a hot plate. After it begins to boil, slowly add the 2.7 grams of gelatin into the beaker while stirring. After it is fully dissolved, pick up the beaker using tongs and pour the mixture evenly among 6 test tubes (try and get as few air bubbles as possible). After it has been evenly distributed, add .6 mL of laundry detergent each to only two of the test tubes, and stir well. After using the parafilm wax strips to securely cover the tube by holding the wax for 30 seconds in hand, label these two tubes as “LD”. Then, add .6 mL of meat tenderizer to two other tubes, and again, stir well.
Add parafilm in the same fashion as the last two tubes to these two, label them “MT”. Leave the last two tubes without any enzyme addition, cover with parafilm, and do not label the pair. Once this is completed, carefully place test tube racks with the recently filled test tubes somewhere safe, preferably the back of the lab tables. Carefully clean up any sort of mess that was made during the lab for today, leaving the lab table clean. Leave test tubes untouched for 48 hours. After the time period carefully observe the test tubes, taking notes on the differences you see. Using the data gathered, answer any questions left blank on the worksheet. Afterwards, be sure to carefully clean any equipment used and all of the lab area.
IV: Enzyme type added to gelatin mixture
DV: The effect of the enzymes on the gelatin mixture after 48 hours Control Group: Test tubes containing only the gelatin mixture Constants:
-meat tenderizer type/brand
-laundry detergent type/brand
-shape and size of test tube
Class Data: based on a scale from 1-10, 1 being the least runny and 10 being the most runny
Control Group Detergent Group Meat Tenderizer Group Group 13,6
Observation after 48 hours chart:
Test Tubes of Gelatin:Observation for 1st test tubeObservation for 2nd test tube With meat tenderizer added Foggy/ tan in color
Somewhat movableFoggy/ tan in color
Not very moveable
With laundry detergent addedBlue in color
Water-likeBlue in color
Control groupClear in color
Not moving at allClear in color
Not moving at all
Analysis of Data: After looking at the data collected, a pretty general pattern within the test tubes is seen, as in consistency and color, despite some, but few, differences in consistency within the meat tenderizer mixture. For example, some groups had less runny results within the meat tenderizer, and others had almost completely runny substances in test tubes.
Conclusion: In this lab, the difference in two enzymes, and how they have different effects on gelatin, was discovered. There were widespread differences between the control and experimental groups. The control, for example was consistently runny. Then, looking at the experimental groups, one is consistently runny, and the other varies from more runny to barely runny. Meat tenderizer is used in meat to break it down partially, not completely. If meat were to be left for too long within the papain or the papain mixture, the meat would become runny and gross. The Indians of Central America used papain because they figured out that it helped to make the meat tenderer. If fresh pineapples were to be added to Jell-O, because it contains an enzyme similar to papain, it would probably have the same outcome as the meat tenderizer mixture.
On the other hand, canned pineapple, because it is processed, would have a different outcome because the enzyme has also been processed. Meat tenderizer can also be used on insect and jellyfish stings. This is because meat tenderizer helps to breakdown the proteins within the sting. With the laundry detergent, it was discovered that the detergent uses enzymes to break down things, most commonly stains within clothes. Proteases are used in detergents because they are designed to break down proteins, also known as stains. The enzyme that was found in the detergent used in the lab was amalayse and protease.
Finally, within the plain gelatin and water mixture, it was discovered that gelatin, when mixed with water does, in fact, turn into a gel formation when it is left to sit. Certain errors were discovered in this lab, however. For example, some groups let the water cool too long, and so the same results were achieved. Also, not everyone followed the instructions exactly, and so the data was a bit different from the rest of the groups. In a future experiment, different enzymes should be used so that the differences in other enzymes can be shown through a lab. In all, this experiment teaches how different enzymes work within daily life and how different enzymes carry out different processes that are used by humans for specific products.