Lab 1. Osmosis And Diffusion: Why Do Red Blood Cells .
Lab 1. Osmosis and Diffusion: Why Do Red Blood Cells Appear Bigger AfterBeing Exposed to Distilled Water?IntroductionAll living things are made of cells. Some organisms, such as bacteria, are unicellular, which meansthey consist of a single cell. Other organisms, such as humans, fish, and plants, are multicellular,which means they consist of many cells. All cells have some parts in common. One part foundin all cells is the cell membrane. The cell membrane surrounds the cell, holds the other parts ofthe cell in place, and protects the cell. Molecules such as oxygen, water, and carbon dioxide canpass in and out of the cell membrane. All cells also contain cytoplasm. The cytoplasm is a jelly-likesubstance inside the cell where most of the cell’s activities take place. It’s made out of water andother chemicals.Some cells found in multicellular organisms are highly specialized and carry out very specificfunctions. An example of a specialized cell found in vertebrates is the erythrocyte, or red blood cell(RBC). RBCs are by far the most abundant cells in the blood. The primary function of RBCs is totransport oxygen from the lungs to the cells of the body. In the capillaries, the oxygen is released soother cells can use it. Ninety-seven percent of the oxygen that is carried by the blood from the lungsis carried by hemoglobin; the other 3% is dissolved in the plasma. Hemoglobin allows the blood totransport 30–100 times more oxygen than could be dissolved in the plasma alone.As you can see in the figure to theright, RBCs look like little discs when Red blood cells before and after distilled water is addedthey are viewed under a microscope.They have no nucleus (the nucleus isextruded from the cell as it matures tomake room for more hemoglobin). Aunique feature of RBCs is that they canchange shape; this ability allows themto squeeze through capillaries withoutbreaking. RBCs will also change shape inresponse to changes in the environment.For example, if you add a few drops ofdistilled water to blood on a microscopeslide, the cells will look bigger after a few seconds (see the figure’s right panel).Scientists often develop and test explanations for natural phenomena. In this investigation youwill have an opportunity to design and carry out an experiment to test two different explanationsfor why RBCs appear bigger after they are exposed to distilled water. These are the two explanations that you will test:1. Molecules such as protein and polysaccharides are more concentrated inside the cell thanoutside the cell when the cell is in distilled water. These molecules therefore begin to moveout of the cell because of the process of diffusion but are blocked by the cell membrane. Asa result, these molecules push on the cell membrane and make the cell appear bigger.2. Water molecules move into the cell because the concentration of water is greater outsidethe cell than it is inside the cell. As a result, water fills the cell and makes it appear bigger.Your TaskDesign and carry out an experiment to determine which of the two explanations about the appearance of RBCs after exposure to distilled water is the most valid or acceptable from a scientificperspective.The guiding question of this investigation is, Why do the red blood cells appear bigger afterbeing exposed to distilled water?MaterialsYou may use any of the following materials during your investigation: Starch solution (starch is a Balance (electronic or triple beam)polysaccharide) Dialysis tubing (assume that it behaves Distilled waterjust like the membranes of RBCs) Beakers Safety goggles Graduated cylinder Aprons
Safety Precautions1.2.3.Indirectly vented chemical-splash goggles and aprons are required for this activity.Wash hands with soap and water after completing this lab.Follow all normal lab safety rules.Getting StartedYou will use models of cells rather than real cells during your experiment. You will use cell modelsfor two reasons: (1) a model of a cell is much larger than a real cell, which makes the process ofdata collection much easier; and (2) you can create your cell models in any way you see fit, whichmakes it easier to control for a wide range of variables duringyour experiment. The cell models will therefore allow you to Tying the dialysis tubingdesign a more informative test of the two alternative explanationsoutlined above.You can construct a model cell by using the dialysis tubing.Dialysis tubing behaves much like a cell membrane. To createa model of a cell, place the dialysis tubing in water until it isthoroughly soaked. Remove the soaked tubing from the waterand tightly twist one end several times and either tie with stringor tie a knot in the tubing. You can then fill the model cell witheither a starch solution (starch is a common polysaccharide) ordistilled water. Once filled, twist the open end several times andtie it tightly as shown in the figure to the right. You can then drythe bag and place it into any type of solution you need.In designing your experiment, you must determine what typeof data you will need to collect, how you will collect it, and how you will analyze it. To determinewhat type of data you will need to collect, think about the following questions: What will serve as your dependent variable (e.g., mass of the cell or size of the cell)? What type of measurements will you need to make during your investigation?To determine how you will collect your data, think about the following questions: What will serve as a control (or comparison) condition? What types of treatment conditions will you need to set up and how will you do it? How many “cells” will you need to use in each condition? How often will you collect data and when will you do it? How will you make sure that your data are 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 the data?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 conditions and thecontrol condition? What type of calculations will you need to make? What type of graph could you create to help make sense of your data?Investigation Proposal Required? Yes NoConnections to Crosscutting Concepts and to the Nature of Science and the Nature ofScientific InquiryAs you work through your investigation, be sure to think about the importance of identifying the underlying cause for observations, how models are used to study natural phenomena, how matter moves within or through a system, the difference between data and evidence in science, and the nature and role of experiments in science.
Argumentation SessionArgument presentation on a whiteboardOnce your group has finished collecting and anaThe Guiding Question:lyzing your data, prepare a whiteboard that you canuse to share your initial argument. Your whiteboardOur Claim:should include all the information shown in thefigure to the right.Our Evidence:Our JustificationTo share your argument with others, we will beof the Evidence:using a round-robin format. This means that onemember of your group will stay at your lab stationto share your group’s argument while the othermembers of your group go to the other lab stationsone at a time to listen to and critique the argumentsdeveloped by your classmates.The goal of the argumentation session is not toconvince others that your argument is the best one; rather, the goal is to identify errors or instancesof faulty reasoning in the arguments so these mistakes can be fixed. You will therefore need toevaluate the content of the claim, the quality of the evidence used to support the claim, and thestrength of the justification of the evidence included in each argument that you see. In order tocritique an argument, you will need more information than what is included on the whiteboard.You might, therefore, need to ask the presenter one or more follow-up questions, such as: How did you collect your data? Why did you use that method? Why did you collectthose data? What did you do to make sure the data you collected are reliable? What did you do todecrease measurement error? What did you do to analyze your data? Why did you decide to do it that way? Did youcheck your calculations? Is that the only way to interpret the results of your analysis? How do you know that yourinterpretation of your analysis is appropriate? Why did your group decide to present your evidence in that manner? What other claims did your group discuss before you decided on that one? Why did yourgroup abandon those alternative ideas? How confident are you that your claim is valid? What could you do to increase yourconfidence?Once the argumentation session is complete, you will have a chance to meet with your groupand revise your original argument. Your group might need to gather more data or design a way totest one or more alternative claims as part of this process. Remember, your goal at this stage of theinvestigation is to develop the most valid or acceptable answer to the research question!ReportOnce you have completed your research, you will need to prepare an investigation report thatconsists of three sections that provide answers to the following questions:1. What question were you trying to answer and why?2. What did you do during your investigation and why did you conduct your investigationin this way?3. What is your argument?Your report should answer these questions in two pages or less. This report must be typed,and any diagrams, figures, or tables should be embedded into the document. Be sure to write in apersuasive style; you are trying to convince others that your claim is acceptable or valid!
Lab 2. Cell Structure: How Should the Unknown Microscopic Organism BeClassified?IntroductionPlant and animal cells have many organelles in common, includingthe nucleus, nucleolus, nuclear envelope, rough and smooth endoplasmic reticulum, Golgi apparatus, ribosomes, cell membrane, andmitochondria. Some organelles found in plant cells, however, are notfound in animal cells and vice versa. For example, animal cells havecentrioles (which help organize cell division in animal cells), but plantcells do not. These differences can be used to distinguish between cellsthat come from a plant and cells that come from an animal. The figureto the right shows animal cells from the inside of a human cheek.Human cheek cellsYour TaskDocument the traits of an unknown microscopic organism. Then classify it based on what youknow about the characteristics of plant and animal cells.The guiding question of this investigation is, How should the unknown microscopic organismbe classified?MaterialsYou may use any of the following materials during your investigation: Known slide A (plant cells) Known slide D (animal cells) Known slide B (plant cells) Slide with an unknown organism Known slide C (animal cells) MicroscopeSafety Precautions1.2.3.4.Glass slides can have sharp edges—handle with care to prevent cutting of skin.Use caution when working with electrical equipment. Keep away from water sources inthat they can cause shorts, fires, and shock hazards. Use only GFI-protected circuits.Wash hands with soap and water after completing this lab.Follow all normal lab safety rules.Getting StartedTo answer the guiding question, you will need to conduct a systematic observation of the cellsamples provided. To accomplish this task, you must first determine what type of data you willneed to collect, how you will collect it, and how you will analyze it. To determine what type of datayou will need to collect, think about the following questions: What type of measurements or observations will you need to make during your investigation? How will you quantify any differences or similarities you observe in the different cells?To determine how you will collect your data, think about the following questions: How will you make sure that your data are 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 the data?To determine how you will analyze your data, think about the following questions: How will you define the different categories of cells (e.g., what makes a plant cell a plantcell, what makes an animal cell an animal cell)? What type of calculations will you need to make? What type of graph could you create to help make sense of your data?Investigation Proposal Required? Yes NoConnections to Crosscutting Concepts and to the Nature of Science and the Nature ofScientific InquiryAs you work through your investigation, be sure to think about the importance of looking for patterns during an investigation,
how structure is related to function in organisms, the different type of methods that are used to answer research questions in science, and the importance of imagination and creativity in science.Argumentation SessionArgument presentation on a whiteboardOnce your group has finished collecting and anaThe Guiding Question:lyzing your data, prepare a whiteboard that you canuse to share your initial argument. Your whiteboardOur Claim:should include all the information shown in the figure to the right.Our Evidence:Our JustificationTo share your argument with others, we will beof the Evidence:using a round-robin format. This means that onemember of your group will stay at your lab station toshare your group’s argument while the other membersof your group go to the other lab stations one at a timeto listen to and critique the arguments developed byyour classmates.The goal of the argumentation session is not toconvince others that your argument is the best one;rather, the goal is to identify errors or instances of faulty reasoning in the arguments so thesemistakes can be fixed. You will therefore need to evaluate the content of the claim, the quality of theevidence used to support the claim, and the strength of the justification of the evidence included ineach argument that you see. In order to critique an argument, you will need more information thanwhat is included on the whiteboard. You might, therefore, need to ask the presenter one or morefollow-up questions, such as How did you collect your data? Why did you use that method? Whydid you collect those data? What did you do to make sure the data you collected are reliable? What did you do todecrease measurement error? What did you do to analyze your data? Why did you decide to do it that way? Is that the only way to interpret the results of your analysis? How do you know that yourinterpretation of your analysis is appropriate? Why did your group decide to present your evidence in that manner? What other claims did your group discuss before you decided on that one? Why did yourgroup abandon those alternative ideas? How confident are you that your claim is valid? What could you do to increase yourconfidence?Once the argumentation session is complete, you will have a chance to meet with your groupand revise your original argument. Your group might need to gather more data or design a way totest one or more alternative claims as part of this process. Remember, your goal at this stage of theinvestigation is to develop the most valid or acceptable answer to the research question!ReportOnce you have completed your research, you will need to prepare an investigation report thatconsists of three sections that provide answers to the following questions:1. What question were you trying to answer and why?2. What did you do during your investigation and why did you conduct your investigationin this way?3. What is your argument?Your report should answer these questions in two pages or less. This report must be typed,and any diagrams, figures, or tables should be embedded into the document. Be sure to write in apersuasive style; you are trying to convince others that your claim is acceptable or valid!
Lab 3. Cell Cycle: Do Plant and Animal Cells Spend the Same Proportion ofTime in Each Stage of the Cell Cycle?IntroductionThe cell cycle is an important process, and we need to understand it to appreciate how animalsand plants are able to grow, heal, and reproduce. The figure below provides pictures of plant andanimal cells in various stages of the cell cycle.The cell cycle of (a) plant cells and (b) animal cells(a)(b)The picture of the plant cells was taken from the cells in the tip of an onion root. The roots ofplants are good for studying the cell cycle because they are constantly growing and, as a result,many of the cells in the tip of the root are in the process of dividing. To create the picture in thefigure (a) above, a very thin slice of onion root was placed onto a microscope slide. The root wasthen stained with a dye that made the chromosomes visible. These photos provide us with a clearview of the various stages of the cell cycle, yet this information tells us little about how long a cellspends in each stage and if the amount of time in each stage is different for plants and animals.To figure out how long cells spend in each stage of the cell cycle, we need to look at the proportion of cells in a given area that are in each phase. From this information you can then determinethe relative amount of time a cell spends in each stage. The portion of cells in each phase shouldcorrespond closely with the amount of time spent by each cell in each phase.Your TaskDetermine the proportion of time animal and plant cells spend in each phase of the cell cycle.The guiding question of this investigation is, Do plant and animal cells spend the same proportion of time in each stage of the cell cycle?MaterialsYou may use any of the following materials during your investigation: A prepared slide from an onion root tip A prepared slide from a whitefish blastula MicroscopeSafety Precautions1.2.3.4.Glass slides can have sharp edges—handle with care to prevent cutting of skin.Use caution when working with electrical equipment. Keep away from water sources inthat they can cause shorts, fires, and shock hazards. Use only GFI-protected circuits.Wash hands with soap and water after completing this lab.Follow all normal lab safety rules.Getting StartedTo answer the guiding question, you will need to design and conduct an investigation. You will bepresented with slides that you can use to see the cells in the tip of an onion root and in a whitefish
blastula. Both slides will have cells in various stages of the cell cycle. To accomplish this task, youmust determine what type of data you will need to collect, how you will collect it, and how you willanalyze it. To determine what type of data you will need to collect, think about the following questions: What type of measurements or observations will you need to record during yourinvestigation? How will you quantify any differences or similarities you observe in the different cells?To determine how you will collect your data, think about the following questions: How will you determine how many cells are in each stage on each slide (i.e., how manycells are in interphase, how many cells are in metaphase, and so on)? How will you make sure that your data are of high quality (i.e., how will you reduceerror)? How will you keep track of the data you collect and how will you organize the data?To determine how you will analyze your data, think about the following questions: What type of calculations will you need to make? (Hint: You will need to determine thenumber of cells in each stage and the total number of cells you counted and use thosenumbers to predict how much time a dividing cell spends in each phase.) What type of graph could you create to help make sense of your data?Investigation Proposal Required? Yes NoConnections to Crosscutting Concepts and to the Nature of Science and the Nature ofScientific InquiryAs you work through your investigation, be sure to think about the importance of identifying and explaining patte
The cell membrane surrounds the cell, holds the other parts of the cell in place, and protects the cell. Molecules such as oxygen, water, and carbon dioxide can pass in and out of the cell membrane. All cells also contain cytoplasm. The cytoplasm is a jelly-like substance inside the cell where most of the cell’s activities take place.
Lab 4: Diffusion and Osmosis (Revised Fall 2009) Lab 4 - Biol 211 - Page 1 of 23 Lab 4. Diffusion and Osmosis in Selectively Permeable Membranes Prelab Assignment Before coming to lab, read carefully the introduction and the procedures for each part of the experiment, and then answer the prelab q
AP BIOLOGY NAME_ CELL UNIT ACTIVITY #6 DATE_HOUR_ DIFFUSION AND OSMOSIS LAB INTRODUCTION: In this laboratory you will investigate the processes of diffusion and osmosis in a model membrane system. You will also investigate the effect of solute concentration on w
energy –referring to active transport, exocytosis and endocytosis. The correct processes that the molecules Louise was may utiliseinclude A. osmosis, simple diffusion and active transport. B. osmosis and simple diffusion. C. osmosis and exocytosis. D. simple diffusion, exocytosis and endocytosis
Diffusion, Osmosis, and Osmoregulation NOTES January 23, 2012 Passive vs. Active Transport Passive Transport - the movement of molecules, into or out of cells, with the concentration gradient. * No energy required by the cell. * Examples: diffusion and osmosis *Active Transport - the movement of molecules, into or out of cells, against the .
EMA 5001 Physical Properties of Materials Zhe Cheng (2016) 4 Self-Diffusion & Vacancy Diffusion Diffusion of Vacancy vs. Substitutional Atoms Continue from p. 7 2 Therefore, Diffusion coefficient of vacancy vs. substitutional atom For self-diffusion 2 The relationship between jump frequency is Since the jump distance is the same
PRE-LAB ASSESSMENT These questions are designed to help you understand kinetic energy, osmosis, and diffusion and to prepare for your investigations. All lab questions should be answered in thorough, complete sentences. 1) What is kinetic energy, and how does it differ from potential energy? (2 pt) 2) What environmental factors affect .
Select Lab 1: Diffusion & Osmosis Complete the virtual lab activity and record your responses in this packet. Introduction The processes of diffusion and osmosis account for much of the passive movement of molecules at the cellular level. In this laboratory, you will study some of the basic principles of molecular movement in solution and .
Biology Lab Notebook Table of Contents: 1. General Lab Template 2. Lab Report Grading Rubric 3. Sample Lab Report 4. Graphing Lab 5. Personal Experiment 6. Enzymes Lab 7. The Importance of Water 8. Cell Membranes - How Do Small Materials Enter Cells? 9. Osmosis - Elodea Lab 10. Respiration - Yeast Lab 11. Cell Division - Egg Lab 12.
