Exam One Lab Study Guide
Exam One Lab Study Guide BIOL 1040
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This 14 page Study Guide was uploaded by kqmorgan on Sunday February 28, 2016. The Study Guide belongs to BIOL 1040 at Bowling Green State University taught by Tamera Wales in Fall 2015. Since its upload, it has received 92 views. For similar materials see Intro to Biology in Biology at Bowling Green State University.
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Date Created: 02/28/16
BIO 1040 Lab Exam Review Unit 1: Exercise 1-6 *These questions are taken directly from the pre- and post-labs of each experiment. Please remember to review the questions found in the back of the lab manual in addition to this information, though the questions in the back of the book go unnecessarily in-depth so I recommend spending more time reviewing this material than that material. Happy studying! The Scientific Method Post-Lab (First Lab- No Prelab) 1. How does the modern scientific method differ from the natural philosophy of the ancient Greeks? a. Natural philosophy accepted the idea of absolute truth. Scientific method encourages experimentation or pertinent observation, though former methods did not. 2. List the six steps of one full cycle of the scientific method. a. Observe b. Question c. Hypothesize d. Predict e. Test f. Conclude 3. Within the framework of an experiment, define the following terms a. Independent Variable i. The treatment or condition under the study b. Dependent Variable i. The event or condition that is measured or observed when the results are gathered c. Controlled Variables i. All other factors, which the investigator attempts to keep the same for all the groups under study 4. Is a scientific principle taken as absolutely true? Explain your answer. a. No- “The scientific method cycles over and over again, each turn further refining the hypothesis.” The method does not suppress testing, it encourages testing. 5. What is the function of research articles in scientific journals? a. These articles allow scientists to share knowledge, repeat experiments, and expose mistakes 6. Why is it important to use sterile techniques while creating a lawn of bacteria? a. This is important so that the work environment/experiment is not contaminated Microscopy Prelab 1. A bacterium is an example of a(an): a. Prokaryotic cell 2. Prokaryotic cells lack: a. A true nucleus 3. The person responsible for first using the term cell was: a. Hooke 4. The word eukaryotic refers specifically to a cell containing: a. A true nucleus 5. The intercellular space between plant cells: a. Contain air 6. A central vacuole: a. Is found only in plant cells and may take up between 50% and 90% of the cell’s interior 7. Methylene blue: a. Is a biological stain used to increase contrast of cellular constituents 8. Components typical of plant cells but not of animal cells are: a. Cell walls 9. The two image-forming lenses of a compound light microscope are: a. The objective and ocular 10. All cells contain: a. DNA, plasma membrane, and cytoplasm Microscopy Post-Lab 1. When students are asked to distinguish between an animal cell and a plant cell, they typically answer the plant cells contain chloroplasts and animal cells do not. If you were the professor reading that answer, what sort of credit would you give why? a. Chloroplasts are made during photosynthesis. I would not give credit 2. Look at the photomicrograph below taken with a technique that gives a three-dimensional impression. Identify the structures labeled A and B. a. Chloroplasts (Ball-Shaped) b. Cell Wall (Outlines) 3. What structure(s) found in plant cells are primarily responsible for cellular support? a. Vacuole 4. What is the function of the following parts of a compound light microscope? a. Condenser Lens i. Focuses the light source on the specimen b. Iris Diaphragm i. Controls the width of the circle of light c. Objective i. “Scans the specimen” d. Ocular i. This is the eyepiece 5. In order, list the lenses in the light path between a specimen viewed with the compound light microscope and its image on the retina of the eye. a. Diaphragm -> Objective lens -> Nosepiece -> Ocular -> Eyes 6. What happens to the field of view in a compound light microscope when the total magnification is increased? a. The field of view is limited, but the view becomes more detailed 7. Describe how you would care for and put away your compound light microscope at the end of the lab. a. I would turn off the microscope, unplug it, wrap the cord around it, and then put the cover over it 8. Describe how to make a wet mount. a. Place specimen on slide b. Drop water on specimen c. Cover with plastic slide 9. Why were humans unaware of microorganisms for most of their history? a. They were not visible to the naked eye Macromolecules Prelab 1. To test for starch one would use: a. Lugol’s solution 2. Rich sources of stored energy that are dissolvable in organic solvents are: a. Lipids 3. A protein is made up of: a. Amino acid units 4. The largest number of food servings in your daily diet should be from: a. Bread, cereal, rice, pasta 5. Rubbing a substance on uncoated paper should reveal if it is a: a. Lipid 6. A carbohydrate consists of: a. One or more sugar units 7. Glycogen is: a. A storage carbohydrate 8. Benedict’s solution is commonly used to test for: a. Certain carbohydrates 9. Biuret reagent will indicate the presence of: a. Peptide units linked together 10. Which of the following does not occur in plants? a. Glycogen Macromolecules Post-Lab 1. Let’s suppose that you are worried that you’ve developed diabetes, a condition in which blood glucose levels rise and glucose accumulates in the urine. Not having immediate access to a physician, but recalling what you learned in this lab exercise, what could you do to determine whether you have diabetes? a. Benedict’s solution could be mixed with the urine, then heated. If it turned orange or red, it could be determined that the individual had high levels of sugar in their urine and therefore may have diabetes. 2. The test tubes in the photograph contain Benedict’s solution and two unknown substances that have been heated. What do the results indicate? a. The results indicate that the substance on the right contains sugars, while the substance on the left does not. 3. How could you verify that a soft-drink can contains diet soda rather than soda sweetened with fructose? a. The normal soda would turn brown when tested with Benedict’s solution and heated. The diet soda would remain clear. 4. The test tube in the photograph contains water at the bottom and another substance that has been stained with Sudan IV at the top. What is the macromolecular composition of this stained substance? a. The substance would be a lipid because of its red color. The substance would therefore consist of a hydrocarbon chain with a carboxyl (-COOH). 5. You are given a sample of unknown food. Describe how you would test it for the presence of lipids. a. I would test for the presence of lipids by adding Sudan IV to the food, and agitating the new mixture. If the food turned red, I would understand that it contained lipids. 6. You wish to test the same unknown food for the presence of sugars. Describe how you would do so. a. I would test the food for sugars by adding Benedict’s solution and heating the new mixture. If the food turned orange or red, I would understand that it contained sugars. 7. What is the purpose of the distilled water sample in each of the chemical tests in this exercise? a. The distilled water is used as the control group in each experiment. Diffusion Prelab 1. Which of the following reagents does not fit with the substance being tested for? a. BaCl , starch 2 2. A solvent is: a. The substance in which solutes are dissolved 3. Specifically, osmosis a. Is diffusion of water across a selectively permeable membrane 4. An example of a solute would be: a. Janus Green B and sucrose 5. If one solution contains 10% NaCl and another contains 30% NaCl, the 30% solution is _______ with respect to the 10% solution. a. Hypertonic 6. Dialysis membrane is: a. Selectively permeable, used in these experiments to simulate cellular membranes; and permeable to water but not to sucrose 7. If one were to identify a single most important compound for sustenance of life, it would probably be: a. Water 8. Cellular membranes: a. Consist of a phospholipid bilayer containing embedded proteins; control the movement of substances into and out of cells; and are selectively permeable 9. Diffusion: a. Is the movement of molecules from a region of higher concentration to one of lower concentration 10. Refer to Table 1. Which of the molecules would you expect to diffuse the furthest when added to a permeable gel (the substance of Jell-O)? a. Potassium dichromate Diffusion Post-Lab 1. You want to dissolve a solute in water. Without shaking or swirling the solution, what might you do to increase the rate at which the solute would go into the solution? Relate your answer to your method’s effect on the motion of the molecules. a. The solution could be heated to increase the rate of diffusion. 2. If a 10% sugar solution is separated from a 20% sugar solution by a selectively permeable membrane, in which direction will there be a net movement of water. a. It would move from a high concentration to a low concentration. 3. Based on your observations in this exercise, would you expect dialysis membrane to be permeable to sucrose? Why? a. I would not expect this because the membrane keeps out sugars. 4. You are having a party and you plan to serve celery, but your celery has gone limp, and the stores are closed. What might you do to make the celery crisp (turgid) again? a. You might put this celery in the water. 5. Why don’t plant cells undergo osmotic lysis? a. They have a cell wall, which facilitates osmosis and does not allow the intake of too much water. 6. This drawing represents a plant cell that has been placed in a solution. What process is taking place in the direction of the arrows? What is happening at the cellular level when a wilted plant is watered and begins to recover from the wilt? a. Osmosis is taking place in the direction of the arrows. b. The plant is taking in water, but not other substances. 7. How does diffusion differ from osmosis? a. Diffusion moves solutes into the cell while osmosis moves only water into the cell. 8. Plant fertilizer consists of numerous different solutes. A small dose of fertilizer can enhance plant growth, but over fertilization can kill the plant. Why might over fertilization have this effect? a. The concentration of solute is too high, so the plant cannot get enough water. Enzymes Prelab 1. Catechol oxidase: a. Is an enzyme found in potatoes 2. Enzymes function by: a. Lowering the activation energy of a reaction 3. pH is a measure of a. The hydrogen ion concentration 4. The relative color intensity used in the experiments of this exercise: a. Is a consequence of production of benzoquinone; is an index of enzyme activity; and may differ depending on the pH, temperature, or presence of cofactors, respectively 5. Enzymes are a. Biological catalysts; agents that speed up cellular reactions; and proteins 6. Enzyme specificity refers to the a. Fact that enzymes catalyze one particular substrate or a small number of structurally similar substrates 7. The substance that an enzyme combines with is a. The substrate 8. Refer to figure 3 showing the browning of a cut potato. What is responsible for the brown color? a. Benzoquinone 9. What would you expect the pH optimum to be for an enzyme secreted into your stomach? a. Low, in acid range 10. Is it necessary for a cell to produce one enzyme molecule for every substrate molecule that needs to be catalyzed? a. No. Enzymes are not used up during reactions so they can be reused Enzymes Post-Lab 1. Explain what happens to catechol oxidase when the pH is on either side of the optimum. a. Slight changes occur in the shape of the active site, slowing down enzyme activity. 2. What would you expect the pH optimum to be for an enzyme secreted into your stomach? a. I would expect the pH optimum to be very acidic, and therefore low in number. It would probably be between pH 1 and pH 4. 3. Is it necessary for a cell to produce one enzyme molecule for every substrate molecule that needs to be catalyzed? Why or why not? a. No, not every cell needs to be reacting at all times 4. Explain the difference between substrate and active site. a. Substrate (The Key): “The reactant in an enzyme-catalyzed reaction. Combine with enzyme molecules to form a temporary enzyme-substrate complex” b. Active Site (The Lock): “A special region of the enzyme where the substrate binds” 5. The photo shows slices of two apples. The one on the left sat on the counter for 15 minutes prior to being photographed. The one on the right was sliced immediately prior to the photo being taken. a. Explain as thoroughly as possible what you see and why the two slices differ. i. The apple slice on the left is more discolored, and appears to have been exposed to the air longer than the slice on the right, which shows no discoloration. b. If you don’t want a cut apple to brown, what can you do to prevent it? i. You can cover them so that they are not exposed to the air (or add lemon juice!) Photosynthesis Prelab 1. The raw materials used for photosynthesis include: a. CO + 2 O 2 2. Products and byproducts of photosynthesis do NOT include a. CO 2 3. Which reagent would you use to determine the distribution of the carbohydrate stored in leaves? a. I 2l 4. An example of a heterotrophic organism is a. A human 5. Organisms capable of producing their own food are known as a. Autotrophs 6. The ultimate source of energy trapped during photosynthesis is a. Sunlight 7. In what form in glucose usually stored in a leaf a. Starch 8. Which has a lower boiling point? a. Alcohol 9. In the Coleus leaf experiment, what visible indication is there of all the chlorophyll having been extracted? a. Alcohol appears green 10. Pink colors associated with Coleus are due to: a. Anthocyanin pigment Photosynthesis Post-Lab 1. Is starch stored in the leaves of some plants? Would you expect leaves in a temperate climate plant to be the primary area for long-term starch storage? Why or why not? What part(s) of a plant might be better-suited for long-term starch storage? a. Yes, it is. The stems are probably better for the long-term storage of water than leaves are because they are far more durable. 2. Describe an experiment that would allow you to determine whether the deep purple portion of the Coleus leaf is photosynthesizing. a. I would separate the green part of the leaf from the purple, and test the separated parts the way that we did in class. 3. Numerous hypotheses have been proposed for the extinction of the dinosaurs. Recently, evidence has been found of the impact of a large meteor at about the time of this mass extinction. The amount of dust and debris put into the atmosphere upon impact, as well as atmospheric heating, would have been enormous. Using your knowledge of photosynthesis, speculate as to why the dinosaurs subsequently became extinct. a. It may have been hard for plants to photosynthesize. The lack of autotrophs would have left heterotrophs to starve. 4. Explain the statement: “Without autotrophic organisms, heterotrophic life would cease to exist.” a. Heterotrophs rely on autotrophs for food (and therefore energy). If autotrophs disappear, heterotrophs starve. *All questions are taken directly from the lab manual. Though I compiled the study guide, the information used to make it is the work of Kamau W. Mbuthia, Ph.D. Lab Manual: Mbuthia, K.W. “Laboratory Manual for Introduction to Biology 1040.” Lab handbook. Bowling Green State University. Bowling Green, OH. 2014. Print.
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