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Next Generation Curriculum-embedded Science Performance Task Grade/ Course Middle School/ Life Science Task Name THE LINKAGE OF DIFFUSION AND HUMAN BODY SYSTEMS Task Summary In this performance task students will use demonstrations of osmosis and diffusion experiments to observe the movement of water, sugars and starches across artificial and natural membrane systems. Students will develop schematic drawings to model and explain the movement of molecules across the cell membrane as an essential component of cell function. Students will use their understanding of simple membrane functions at the cellular level, combined with online & literature research to write a paper on the topic, ”Importance of Diffusion in the human body”. In their paper student groups will use arguments, supported by their schematic drawing models, and evidence from their research and experimental findings to explain how cell-based organ systems depend on diffusion as an important part of their normal functioning. NGSS PE (s) MS-LS1-2. Develop and use a model to describe the function of a cell as a whole and ways parts of cells contribute to the function. MS-LS1-3. Use argument supported by evidence for how the body is a system of interacting subsystems composed of groups of cells. for particular body functions. NGSS DCI(s) (MS-LS1-1)Within cells, special structures are responsible for particular functions, and the cell membrane forms the boundary that controls what enters and leaves the cell. (MS-LS1-2) In multicellular organisms, the body is a system of multiple interacting subsystems. These subsystems are groups of cells that work together to form tissues and organs that are specialized NGSS Practices 2. Developing and using models. A simulation is one type of model that can be used to understand complex systems and generates predictions. 6. Developing explanations. Students need to develop an explanation of how cell-based organ systems depend D R A F T

Transcript of Examples of Diffusion - Colchester Public Schools Web viewOsmosis is the overall movement of water...

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Next Generation Curriculum-embedded Science Performance Task

Grade/ Course Middle School/ Life ScienceTask Name THE LINKAGE OF DIFFUSION AND HUMAN BODY SYSTEMSTask Summary In this performance task students will use demonstrations of osmosis and

diffusion experiments to observe the movement of water, sugars and starches across artificial and natural membrane systems. Students will develop schematic drawings to model and explain the movement of molecules across the cell membrane as an essential component of cell function. Students will use their understanding of simple membrane functions at the cellular level, combined with online & literature research to write a paper on the topic, ”Importance of Diffusion in the human body”. In their paper student groups will use arguments, supported by their schematic drawing models, and evidence from their research and experimental findings to explain how cell-based organ systems depend on diffusion as an important part of their normal functioning.

NGSS PE (s) MS-LS1-2. Develop and use a model to describe the function of a cell as a whole and ways parts of cells contribute to the function.MS-LS1-3. Use argument supported by evidence for how the body is a system of interacting subsystems composed of groups of cells.for particular body functions.

NGSS DCI(s) (MS-LS1-1)Within cells, special structures are responsible forparticular functions, and the cell membrane forms the boundary that controls what enters and leaves the cell.(MS-LS1-2) In multicellular organisms, the body is a system ofmultiple interacting subsystems. These subsystems aregroups of cells that work together to form tissues andorgans that are specialized

NGSS Practices 2. Developing and using models. A simulation is one type of model that can be used to understand complex systems and generates predictions.6. Developing explanations. Students need to develop an explanation of how cell-based organ systems depend on osmosis and diffusion as an important part of their normal functioning.7.Use an oral and written argument supported by evidence to support or refute an explanation or a model for a phenomenon. (MS-LS1-3)Use an oral and written argument supported by empirical evidence and scientific reasoning to support or refute an explanation or a model for a phenomenon or a solution to a problem. (MS-LS1-4)

CT Science Standards

7.2 — Many organisms, including humans, have specialized organ systems that interact with each other to maintain dynamic internal balance.

GRADE-LEVEL CONCEPT 7.2.a.

The cell is filled with a fluid called cytoplasm; cells contain discrete membrane-enclosed structures called organelles that perform specific functions that support the life of the organism. The structure of the organelle is related to its function. The entire cell is surrounded by the plasma membrane that controls the flow of materials into and out of the cell.

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CCSS/Literacy in Science & Technology

GRADE-LEVEL CONCEPT 7.2.b.

1. Systems consist of parts that interact with and influence each other. Parts of a system work together to make the whole entity work. Similarly, each part of an animal body has a specific job to do, and all the different parts work together to support life.

CCSS.ELA-LITERACY.RST.6-8.1

Cite specific textual evidence to support analysis of science and technical texts.

CCSS.ELA-LITERACY.RST.6-8.2

Determine the central ideas or conclusions of a text; provide an accurate

summary of the text distinct from prior knowledge or opinions.

CCSS.ELA-LITERACY.RST.6-8.3

Follow precisely a multistep procedure when carrying out experiments, taking

measurements, or performing technical tasks.CCSS.ELA-LITERACY.RST.6-8.7Integrate quantitative or technical information expressed in words in a text with a version of that information expressed visually (e.g., in a flowchart, diagram, model, graph, or table).

Skill Objective Addressed

NGSS practices as listed above

Context and Alignment

This task is embedded into middle school life science unit after students have completed their learning of human body systems.

Task Characteristics

The task includes three main activities1. Anticipation Guide

Watching a video on “osmosis experiment” to engage students in the inquiry followed by student’s coming up with their notices and wonders. The video will get student’s excited and increase their curiosity about the topic and also get them thinking about the phenomenon (5 min). Each group will then share their wonders with the rest of the class to further increase the inquiry about the topic.Students will then read an article on “Diffusion and human body” to understand the process of diffusion and osmosis and how these processes relate to the functions of human organ system at the cellular level.This article will also allow teachers to assess the students on CCSS, RST. 6-8.1,8.2.

2. Hands on diffusion/osmosis experiment using dialysis tubing and two solutions to observe the movement of water, sugars and starches across artificial membrane systems, and later on students will use the results of their experiment to draw a schematic model.This assignment will help teachers to assess CCSS, RST,6-8.3 , 8.7.

3. Research on the phenomenon of diffusion and osmosis with respect to different body processes, (absorption, gas exchange, and filtration etc.)

4. Write a paper on the topic , “Importance of Diffusion in human body

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systems”Task Materials This performance task requires the use of the following materials

Test tubes, beakers, stirrers, dialysis tubing, ties, molasses, starch, Lugol’s iodine, water, and computers/ reading materials.

Student Learning Objectives

What do students need to understand about the function of cell membranes with respect to the organ systems

Process of osmosis and diffusion Role of cell membranes in the organ system Role of osmosis and diffusion in the functions of organ system Developing a schematic model for the phenomenon of osmosis and diffusion. Use the schematic model to explain how a single cell contributes to the functioning of the organ

system.

Task Administration Overview

Overall Assessment Structure NGSS ConnectionSession 1 Introduction/Anticipation- Introduce students to the

concept of Diffusion and Osmosis by showing a you tube video. The video shows the effect of placing two different eggs in hypo and hypertonic solutions demonstrating the process of osmosis. Students will fill in the chart on I notice/ I wonder after watching the video and share their wonders with the class. Then students will read an article on “Diffusion and human body” to reinforce the concepts and vocabulary related to the topic, and also use the skill on “citing textual evidence “/ “author’s purpose” to show their understanding. (ccss)

Getting the background knowledge to develop a model of the concept on processes of osmosis and diffusion through cell membranes.

Session 2 Performing an experiment on diffusion/osmosis to observe the movement of water, sugars and starches across the artificial cell membrane, (dialysis tubing). Students will analyze the results of the experiment to answer the questions at the end of the experiment. Then students will show their understanding by drawing a schematic model on how diffusion works in the body processes.

Designing the schematic models of the processes of diffusion and osmosis in the human body organ systems.

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Session 3 Provide students with time and access to the internet to perform their research about the movement of molecules across cell membranes in various organ systems. Students will be provided with a resource of websites and some guiding questions to help them focus their research.Students will now use their schematic drawing as well as the resources from their reading, experiment and research to write a paper on the topic“Importance of Diffusion in the human body systems.”The paper should have five paragraphs with an introduction, three paragraphs for the body, and finally a conclusion. Students should cite the sources of their research at the end of the paper.

Use argument supported by evidence in their presentations to explain how the processes of diffusion and osmosis work in different organ systems.

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Student materials for Session 1 Performance Task MS: (LS)

Anticipation Guide

https://www.youtube.com/watch?v=SSS3EtKAzYc

After watching this small clip from you tube complete the following chart along with your team.

We Notice We Wonder

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Diffusion and Human body

Read closely the article on Diffusion and Human body, highlight or underline any important information relevant to the topic, and answer the questions at the end. Cite the evidence from your reading to justify your answers. (CCSS.ELA-LITERACY.RST.6-8.1), (CCSS.ELA-LITERACY.RST.6-8.2)

1) The Cell Membrane The cell is the basic functional unit of all living things. If one is to understand what is happening within an organism, it is necessary to study what is happening to the individual cells within the organism .The cell membrane, sometimes referred to as the plasma membrane, is a phospholipid bilayer that creates a definite boundary between the inside of the cell and the outside of the cell. The structure of cell membrane allows it to easily regulate the materials that enter and exit the cell .

Because the cell membrane allows certain materials to pass through it, and keeps other materials out of it, it is referred to as a semi-permeable or selectively permeable membrane. Much like the security guard at a government center, movement into and out of the cell is highly regulated.

2) Diffusion Water, carbon dioxide, and oxygen are a few substances that are able to pass through the cell membrane without any help from the proteins embedded in the membrane. These materials can simply pass through the membrane without the use of energy and they will do so in an attempt to reach an equal solute concentration inside and outside of the cell. This process is called diffusion, when substances move from a region of high concentration to a region of low concentration. The "goal" of diffusion is to reach a state of equilibrium. This does not mean that movement of molecules stops once equilibrium is reached. Equilibrium is a state of balance, where for every molecule of a substance that moves into a cell, another one moves out of the cell . To visualize diffusion, imagine two rooms that are connected by one door. If the door connecting the two rooms is closed and everyone is crammed into only one of the rooms, as soon as the door opens, people will begin to walk into the other room to spread out. Most likely, they will not all move into the newly opened room. Instead, they will spread out until every area of the two rooms has roughly the same density (or concentration) of people. People will still be able to walk around and mingle, but they will likely readjust so that every part of the room is equally comfortable at all times. Diffusion is an easy concept to model. Simply place a drop of food coloring into a glass of water (being careful to make sure that the fluid in the glass is completely still). The food coloring will slowly spread out in the water until it is evenly mixed throughout.

3) Diffusion In the Human Body Within the body, diffusion is vital to the functioning of the cardiovascular system and other body systems as well. When oxygen is inhaled into the lungs, it ends up at high concentration in the alveoli, the round sacs at the end of the bronchioles. Because blood that is flowing through your lungs is deoxygenated, there is a higher concentration of oxygen inside the alveoli than in the blood. In an attempt to reach equilibrium, the oxygen simply diffuses into the blood across the cells at the alveolar/capillary boundary. Similarly, the blood circulating through the capillaries in your lungs contains high amounts of carbon dioxide that has been picked up as a waste product from cellular

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respiration. The concentration of carbon dioxide in the blood is much higher than it is in the alveoli, and the carbon dioxide moves into the alveolar gas through simple diffusion; it is then exhaled out of the body 7. In regards to cells, simple diffusion is only possible if the material is able to permeate the membrane.

4) Examples of Diffusion Below are examples of diffusion in the body across concentration gradients.Place Particles that move From ToGut Digested food particles Gut cavity Blood in capillary of villus

in small intestineLungs Oxygen Alveolar air space Blood circulating around the

lungsLungs Carbon Dioxide Blood circulating

around the lungsAlveolar air space

Remember: Particles continue to move from a high to a low concentration until all the particles are evenly and randomly distributed.

5) Osmosis Osmosis is simply a special type of diffusion. It occurs when water molecules pass through a partially permeable membrane. Some membranes in plant and animal cells allow certain particles to pass through them but not others. They are partially permeable membranes. During osmosis, more water molecules pass from the pure water into the dilute solution than pass back the other way. This is because there is a higher concentration of water molecules in the pure water than in the solution. This results in more water molecules diffusing across the concentration gradient from the water to the solution. Eventually, the level on the more concentrated side of the membrane will rise, while that on the less concentrated side falls.

6) Osmosis is the overall movement of water from a dilute solution to a more concentrated solution through a partially permeable membrane. This is still like diffusion, as the water is moving from a higher concentration of water to a lower concentration of water. When the concentration of water is the same on both sides of the membrane, the movement of water will be the same in both directions. At this point, the net exchange of water is zero, and the system is in equilibrium. If red blood cells are placed in pure water, water enters them by osmosis and the red blood cells swell up and burst.

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Name: _____________________ Date: ______________

1. What is this article about?

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2. What is the author communicating about in the first paragraph? Why is this information important?

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3. What does the word semipermeable mean? How is this word related to the cell?

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4. In paragraph 2, the author uses an example to visualize diffusion. Does this example help you to understand what diffusion is? How?

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5.What is the relationship of diffusion and human body? Explain with the help of citing textual evidence from the article.

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6. How is osmosis similar and different from diffusion? Use textual evidence to support your answer.

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7. Explain with the help of textual evidence how diffusion takes place in the alveoli and capillaries?

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Osmosis & Diffusion Lab – Dialysis Tubing

BackgroundThe movement of molecules through a cell membrane is termed osmosis or diffusion. Such movement is principally possible because nutritive molecules are smaller than membrane micro pores. If the molecules are too large, no molecular transfer, or diffusion occurs.

Thus, some membranes may transmit selectively and are termed semi-permeable membranes. In the following experiment, cellophane dialysis tubing serves as an excellent representation of the cell membrane. The enclosed tube may, for the purpose of this experiment, be considered a single living cell in greatly enlarged form.

Materials Glucose Solution Starch Solution Iodine Solution Glucose Test Strips Dialysis Tubing String, 400 ml Beaker, 10 mL Graduated Cylinder, Scissors, Ruler

Procedure1. Measure and cut 20 cm of dialysis tubing.2. Place this tubing in a beaker and cover it with water. Allow it to soak for about five minutes.3. Remove the tubing from the water and rub one of the ends between your thumb and

pointer finger to open. Once open, submerge it in water again for about thirty seconds.4. Tie one end of the tubing in an overhand knot5. Measure 5 ml of starch solution using the 10 ml graduated cylinder and pour it into the

tube.6. Thoroughly rinse the graduated cylinder, shake dry, and measure 5 ml of glucose solution.

Pour this into the tubing as well.7. Tie the second end of the tubing in an overhand knot and rinse it under the faucet. Set your

“cell” on a clean surface.8. Fill the 400 ml beaker ¾ full with tap water. Add 10 drops of Iodine solution and stir well.

(Iodine will turn blue-black in the presence of starch).9. Test the solution in the beaker for the presence of glucose by dipping a glucose test strip

into it. After 30 seconds, compare the color on the strip to the color chart on the side of the bottle. Complete the Initial Status information on your data table.

10. Place the artificial cell (the sealed tubing with solutions) into the beaker of solution and allow it to remain undisturbed for 15-20 minutes.

11. Remove the tubing from the beaker and record your observations in the data table for final status of the solution and the bag.

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12. Retest the solution in the beaker and in the bag with a new glucose test strip and record this data in your table.

Data Name ________________________________

MaterialsInitial

ContentsInitial Solution

ColorFinal Solution

Color

Initial Presence of

Glucose

Final Presence of Glucose

BagGlucose & Starch

BeakerH2O + I

Analysis of Results

Answer the following questions on a separate sheet of paper

1. (a) Describe the test results, which show the presence of starch. (b) Can the starch molecules pass through a dialysis membrane? Which results support this conclusion?

2. Is the membrane selectively permeable? Explain.3. Describe and account for any changes that occurred in beaker. Be sure to specify the direction

of movement for each molecule.4. Describe and account for any changes that occurred in the bag. Be sure to specify the direction

of movement for each molecule.5. For each of the following questions, explain your answers using your results. a) Which molecules

pass through the membrane? b) What molecules were unable to pass through the membrane?6. Can you relate the results of this experiment with digestion or absorption?7. Draw and label a schematic model to show the movement of four molecules from the bag into

the beaker and vice versa?

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