Lesson 1 Scientific Method, Chemistry, & Cells 1. Imagine that someone has just discovered a remarkable chemical found in a plant in the tropical rain forest that seems to cure early-stage skin cancer. You have been awarded a large grant from the National Institutes of Health to test the claim that this chemical cures cancer. Explain how you would proceed, using the scientific method as your guide (reference the steps in your plan). Using the “If…then” format, write a hypothesis with one independent and one dependent variable. Underline the independent variable once and the dependent variable twice (or italicize if typing). Be specific and detailed in your description of your controlled experiments. Describe the types of data (results) you would record and what conclusions you could draw based on those data. Observation: Someone might have noticed that a group or community that was exposed to the chemical had a decreased index of cancer cases. Question: Is there something about the properties of the chemical that could cure cancer? Hypothesis: If this chemical cures early-stage skin cancer, and I administer it to patients who have being diagnosed with early-stage skin cancer, then the patients should be cured from early-stage skin cancer after explosion to the chemical. Experiment: The next logical step is to take the field observations and our hypothesis to a close and control environment. Where we can alter, control and observe changes in the conditions of the experiment (controlled experiment). This can be achieved in a laboratory setting. Recruitment face will be executed as follows: One thousand volunteers will be selected. Each participant has to meet a very specific profile: Participants must: be Between the ages of 20-25 years of age. have been diagnosed with early stage skin cancer within 90 days before the start of the study. be male be Caucasian agree to follow a strict diet provided by our registered dietician. Note: all these requirements have to be met by each participant in order reduce the risk of obtaining false results due to variables not contemplated in this study. Subsequent testing will be done in all participants to ensure that every participant is experiencing the early stage of skin cancer. Once the testing face has been completed we will randomly assemble two groups: an experimental and a control group; each group formed by five hundred participants. In the experimental group each participant will receive the chemical in the same dosage and frequency for a period of three months. The control group will receive a placebo (no chemical). Both groups will receive a daily dosage of medication at the same time and in the same conditions. The only difference is that the control group is getting a placebo (no chemical at all). Without a control group we would not be able to conclude whether the experimental group’s cancer was cured due to the chemical given or because of other factors. Both groups of people (experimental and control) should be formed with people around the same age, ethnicity, and cancer stage. Likewise each participant of the study should be subject to the same diet and daily routine in order to reduce alternative factors. These alternative factors could have the potential to alter the results of the experiment. We must identify our dependent and independent variables. The independent variable is the chemical that will be given to the participants in the form a medication-this is the factor that we are trying to test. The dependent variable is the lack or existence of cancer in each participant after the study. Each participant has early-stage skin cancer. Testing will be performed periodically during the experiment to monitor the efficacy of the treatment (chemical given). This experiment was done to prove or disprove whether certain chemical cures early-stage skin cancer. The results that we are going to monitor are the presence or absence of early-stage skin cancer after three months. Therefore, after three months of exposure to the chemical, all patients will be tested for early-stage skin cancer and the results will be analyzed at that point. Predictions: If the chemical works, after three months the participant in the experimental group will be cured from cancer. In contrast, the control group should show no change meaning that the patients in the control group would still have cancer at the end of the experiment. In the opposite scenario, if the chemical is proven to be ineffective, both groups will remain affected by cancer after the experiment. Results: After three months of treatment all participants of the study were tested. The results were as follows: cancer was still present in every participant within the experimental group. Likewise, the control group showed no favorable change in their condition. In both groups, cancer had progressed as it would in any untreated patient. Conclusion: Based in the results obtained from this case study, we can infer that this chemical found in the tropical rain forest had no effect on the cure of early-stage skin cancer. 2. Prokaryotes are microscopic and present in many environments. List several factors that limit prokaryote size explaining how each acts to limit size. Explain why these factors do not limit the environments in which prokaryotes live. What makes prokaryotes so readily adaptable to different environments? The structural composition of prokaryotes gives them the ability to be extremity minute. Prokaryotes lack of a nucleus and their DNA is contained in their cytoplasm. Moreover, Prokaryotes do not contain organelles; they carry on vital functions without the collaboration of them (organelles). Being able to survive, self-nourish and reproduce without organelles, gives prokaryotes its compact characteristic. Because prokaryotes lack the ability to “delegate” responsibility to organelles, the prokaryote must complete all vital biological requirements/functions (eating, reproducing, and getting rid of waste) by itself. Their reduced size allows these functions to be completed more easily. It is easier and less energy consuming to carry on these activities across a petite cell than a large one. In the reproductive aspect, prokaryotes are capable of self-reproduction due to their small size. Prokaryotes lack of sexual organs, rather they reproduce by binary fission. The non-existing need for sexual organs enables prokaryotes to maintain their size. Furthermore, when reproducing by binary fission prokaryotes gain advantage over other living organisms in several ways. The reproduce extremely fast, a single cell is capable of forming a full colony in a period of 20 minutes. This fast replication wouldn’t be possible if they were larger in size. Subsequently, as the binary fission model explains, prokaryotes duplicate their DNA before dividing. This gives them the capability of passing important adaptation characteristics (mutations) to upcoming generations. These mutations provide new generations with the ability to adapt to new adverse environments quicker. 3. Compare cell parts and their functions to the parts and accompanying functions of a human body. Write analogies for as many organelles as you can. For each analogy, first list the cell part, then its function, then the body part and function. State clearly how you think they are analogous. CELL PART Pili FUNCTION ANALOGOUS BODY PART fingers Flagella grasping/attaching to objects synthesizes proteins Protects the plasma membrane and maintains a cells shape Move the cell around Nucleus Protects DNA cranium Plasmodesmata channels connecting adjacent cells blood vessels Vacuole water/chemical storgage respiration kidneys modifies products from the ER Amino acid synthesis intestines Lysome Cell Membrane Mitochondria Golgi Ribosomes stomach skin feet lungs Liver FUNCTION grasping/ attaching to objects breaks down proteins protects/encases all internal body parts movement (crawl, walk, run) protects brain connects all organs, tissues, and muscles together regulates water/makes blood respiration absorption of nutrients and disposal of waste Cleans chemicals and breaks down drugs 1. Pili give the cell the ability to attach itself to surfaces as the fingers give humans the capability to attach themselves to objects. 2. Lysosome synthetizes proteins as the stomach of human breaks down nutrients and makes them ready for absorption. 3. Cell membrane covers and protects the cell as human skin covers and protects the body. 4. Flagella provides cell with motility capabilities as fell allow a human to ambulate. 5. The nucleus protects the DNA as the cranium protects a human’s brain. The DNA controls all functions of a cell; the brain controls all functions of the body. 6. Plasmodesmata connects adjacent cells as blood vessels interconnect different organs in the body. 7. Vacuole stores water in a human kidneys retain water. 8. Mitochondria are responsible for cell reparation as the lungs aid humans to in air exchange. 9. Golgi modifies products from the endoplasmic reticulum and ships these products off. The small intestine adsorbs broken down food from the stomach and absorbs the nutrients and send the rest to the large intestine for disposal. 10. Ribosomes synthetizes amino acids as the liver cleans chemicals and breaks down drugs in the human body.
