Pre lab questions

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Answer the 7 questions with as much detail as possible. The word document is the assignment and the PDF files are there to help.

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Physiological Response of Living Organisms: Pre-Lab Name ___________________________ Date_________________ 1. Define homeostasis and provide an example within the human body. 2. Explain why it might be important to test more than one worm with the same drug. 3. Formulate a hypothesis as to which drug with has the greatest effect on the heart rate of the worm. 4. How would you setup a control for this experiment? Explain your procedure. 5. How many worms should you test? Why might calculating the standard deviation be a good statistical tool when analyzing the data from the effects of the different drugs on the worm’s heart rate? 6. How long should worms be exposed to the drugs? 7. How do you calculate the heart rate of the worm? Guiding Question: Which drug has the greatest and least affect on the pulsation rate of L. variegatus and why? Substance Groups Stimulant Depressant Drugs 1. Caffeine (5 mM) 2. Alcohol (1 mM) 3. Nicotine (0.1 mM) 4. Caffeine (0.1 mM) 5. Alcohol (0.1 mM) 6. Nicotine (0.01 mM) Record a hypothesis explaining how the drug affects living organisms and your prediction about the outcome of your experiment. How can you tell if your evidence supports your hypothesis? Do you think these means are different? Does graphing the standard deviation with the mean change your thinking? Adapted from FSU non-major lab How can you tell if your evidence supports your hypothesis? Adapted from FSU non-major l Adapted from FSU non-major lab How can you tell if your evidence supports your hypothesis? Adapted from FSU non-major lab How can you tell if your evidence supports your hypothesis? mean: 20 SD: 3 What were your data and what was your evidence in this investigation? How are they different? mean: 0 SD: 10 What conclusions can you draw about about how these drugs affect the nervous system from this evidence? Adapted from FSU non-major lab Worm Experimental Design • You will have 4 worms (A,B,C,D) • Take the initial pulse of the worm A 3 times and calculate the average • Expose worm A to the assigned drug for 10 minutes and record pulse 3 times to obtain an average pulse after treatment. • Stager your worms by 5 minutes to provide time to record data in a timely manor. Pulse • Count the number of pulsations over a period of 15 seconds and multiply by 4. • To calculate the change in pulsation – (mean pulse after treatment-mean pulse before treatment) • Finally, calculate the mean change in pulsation rate. Biology 1005L Investigation : Physiological Response of living organisms Introduction: Drugs may be categorized based on the effect they exert on the nervous systems. Today the two categories that you will be investigating are stimulants and depressants. Stimulants act to mimic natural neurotransmitters or by blocking the effects of inhibitory neurotransmitters, resulting in the increase of the pulsation rate and the inability of the organism to maintain a normal heart rate. Alternatively, depressants act to inhibit excitatory neurotransmitters or increase inhibitory ones resulting in a decreased heart rate. When drugs of either class enter an organism, they disrupt homeostasis, the body’s steady state. Homeostasis requires several body systems to work together to regulate its internal environment. One example is the human urinary system. When a person is well hydrated, they will excrete excess water resulting in highly diluted urine. In this case, the urine is clear to light in color. Alternatively, when a person is dehydrated a signal is sent to your brain to increase the levels of antidiuretic hormone (ADH), which results in the kidneys reabsorbing water, keeping it in the body. This results in more concentrated, dark colored urine. Several common drugs may upset these natural mechanisms used to maintain homeostasis. Your Task: Measure the pulsation rate of L. variegates under normal conditions and after exposure to various neural stimulators and neural inhibitors. Use the guiding question to make a claim as to which drug your group thinks will result in the greatest affect and least effect on the pulsation rate of L. variegates. The guiding Question: Which drugs have the greatest and least affect on the pulsation rate of Lumbriculus variegates? Materials: 1. Lumbriculus variegates in New Worm container. 2. Beaker labeled Post-treatment Worms 3. Worm observation Slides 4. Plastic pipettes 5. Water for rinsing pipettes 6. De-ionized water for rinsing worms 7. Compound Microscopes 8. Small petri dishes (4 per group) 9. Stop watches 10. Drug solutions: Ethanol. Caffeine, Nicotine, Ginseng Getting Started. In this investigation you will be exposing L. variegates to controlled levels of drug solution for a controlled amount of time. General windows of drug amounts and duration of exposure will be provided. Your groups will determine the set amounts of drugs and exposure time. Each worm should be tested independently form the others; therefore you will need a small petri dish of drug solution for each worm. Part I 1. Obtain a viewing chamber (2 per groups of 4). 2. Obtain an untreated worm from the New Worm container with the New Worm plastic pipette. Expel the worm into the viewing trough; be sure to include enough water so that the worm is suspended. Remove excess water with chemwipe and wait for worm to adjust to the trough. After a short period of time it will stop wiggling. 3. Observe 4 different worms using the low magnification (set to 10X objective). Also be sure to use the low light intensity to prevent overheating of the worm. 4. Locate the dorsal blood vessel and record the pulse rate for 15-seconds. Multiple this number by 4 to obtain the initial “normal” pulsation rate. Record this for each worm tested 5. Repeat steps 1-5 for each worm tested. Part II Drug treatments: 1. Expose Worm to your assigned drug solution for a period of 10:00 minutes. Stager your samples by 5 minutes. 2. After the duration of the drug treatment has been expired rinse worms to prevent contamination of the viewing chamber. 3. Record pulsation rate. 4. Place worm in post-treatment beaker. Be sure to record three pulsations rates for both the normal and exposed treatments for each worm This way you can include some basic calculations to strengthen your argument. F IGURE 1. DORSAL BLOOD VESSEL OF BLACK WORM The next step is to think about how you will collect the data you need to answer the guiding question and how you will analyze it. In order to determine how you will collect your data, think about the following questions:      What will serve as a control (or comparison) condition? What will serve as the treatment condition(s)? (How long will your group expose the worms to the drugs?) How will you make sure that your data is of high quality (i.e., how will you reduce error)? How will you keep track of the data you collect and how will you organize it? What are some possible biological factors that could affect the worm’s reaction to the drugs? In order to determine how you will analyze your data think about the following questions:    How will you determine if there is a difference between the treatment and the control condition? What type of calculations will you need to make? (mean of pulsation rates and standard deviation of change caused by drugs in pulsation rate) Use excel to make a graph that represents the different treatment groups include the mean change in pulsation rate and standard deviation. Be sure to label the axis of the graph. Report. Once you have completed your research, you will need to prepare an investigation report that consists of three sections. Each section should provide an answer for the following questions in 2 pages or less. This report must be typed and a diagrams, figures, or tables should be labeled and embedded into the document (no attached documents). Generally, you need one page for the first two sections and the second page for the third section.    Section 1: (6 points) What concept were you investigating and how does it relate to the guiding question? Which drugs have the greatest and least affect on the pulsation rate of Lumbriculus variegates? See the introduction on homeostasis and using organisms as models. Specifically discuss how we can measure different physiological characteristics to determine the effect of drugs on organisms. Single paragraph Section 2: (6 points) How did you go about your work and WHY? This is NOT a list of each step of your procedure, but a discussion about the process and the rational for the procedure. Single paragraph Section 3: (15 points) What is your argument? There should be a data table and graph with standard deviation included for the different observations. Be sure to include units and be consistent with your significant figures. Discuss the validity and reliability of your in answering the question. Compare results with other groups. ...
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