diffusion, osmosis & passive transport student self study movement across a semi-permeable...
TRANSCRIPT
Diffusion, Osmosis & Passive Transport Student Self
Study
Movement across a semi-permeable membrane
CAE 507Video & Multimedia
for Educationby
Karen Reback
Nova SoutheasternUniversity
June 10, 2007
Lesson Goals & Learning Objectives:
After viewing the presentation, and accessing the links; students will be able to compare and contrastthe basic mechanisms of passive and active transport across the cell membrane with 100% accuracy
After viewing the presentation, and accessing thelinks; students will be able to describe osmosis and diffusion concepts with 100% accuracy.
These lessons are geared toward High School Biology students
To gain a better understanding of both active and passive transport and how they relate to plant and animal cells
At the cellular level, many things are occurring every second, which we are generallynot able to visualized. Using a large cell (egg), the student will be able to see how the semi-permeable membrane “works”; allowing some materials to pass while others do not. The project will show osmosis, the movement of water across a semi-permeable membrane. Students, will need to read, and interpret the given information and data, drawing conclusions and taking those conclusions to further levels of analysis. Once the student has seen passive transport in action, the student will then need to create, test and complete an original experiment involving some form of passive transport.
Itinerary Front Door - Evaluation Tag CHE (concrete, humanistic, easy)I choose this front door because it patterned after a daily diary, in this case an egg. The evaluation tag “C”oncrete is based on specific facts. “H”umanistic, encourages affective examination of the material. “E”asy this front door can be revised and translated easily.
Begin your virtual tour of movement across a semi-permeable membrane – Click on the given containers to see what happens during that time
Prior to the egg being placed into the vinegar
24 hours after the egg has been placed in the vinegar
48 hours after the egg has been placed in the vinegar
72 hours after the egg has been placed in the vinegar
24 hours after the egg was removed from the vinegar and placed in corn syrup
Lesson Overview• Cellular Transport is movement of materials across a semi-
permeable membrane.• Cellular Transport can be broken into active and passive transport.• Passive Transport is the movement of materials across a semi-permeable. membrane, from an area of high concentration to an area of
low concentration (down the concentration gradient).• Active Transport is the movement across a semi-permeable membrane from an area of low concentration to an area of high concentration. Active transport requires that energy is added.
Instructions• Click on the forward arrow to advance to
the next slide; the back arrow to return to the previous slide. Arrows will have specifically where you are headed if not just front or back. Answer each question carefully.
• Time – You will have 60 minutes to complete the lesson.
What do you know about Cellular Transport?
Which condition might cause a cell to burst? – Click on the cell next to your Answer choice…
A
B
C
D
Which way do you predict water will move and why?Click on the Corresponding Water Molecule for your answer.
From left to right against its concentration gradient.From right to left against its concentration gradient.From left to right along its concentration gradient.From right to left along its concentration gradient.
Active Transport Question
How are the dissolved ions moving?Click on the ion next to your answer:
1. Against their concentration gradient.2. With their concentration gradient.3. From high concentration to low concentration4. Both 1 & 3 More
information
Previous question
The movement of materialsinto and out of the cell is very import to how plants and animal cells function on a daily basis…
As you can see the water molecules are the only thing that passes across the semi-permeable membrane
High Solute – Low Water
Water moves to the left
High Water – Low Solute
Sugar molecules that cannot pass through the membrane
Water molecules can move with the concentration gradient
Hypertonic SolutionHypertonic Solutions: contain a high concentration of solute relative to another solution (e.g. the cell's cytoplasm). When a cell is placed in a hypertonic solution, the water diffuses out of the cell, causing the cell to shrivel.
water
solute
Hypotonic SolutionHypotonic Solutions: contain a low concentration of solute relative to another
solution (e.g. the cell's cytoplasm). When a cell is placed in a hypotonic solution, the water diffuses into the cell, causing the cell to swell and possibly explode.
water
solute
Isotonic SolutionIsotonic Solutions: contain the same concentration of solute as an another solution (e.g. the cell's cytoplasm). When a cell is placed in an isotonic solution, the water diffuses into and out of the cell at the same rate. The fluid that surrounds the body cells is isotonic.
solute
water
Animal CellsAnimal cells are effecteddaily by the differing typesof solutions. Isotonic is when everything is in balance betweenthe cell, blood and bodychemistry. You have experienced a hypertonicsolution, when your cells are put into a into a solution that has more water inside the cell then outside the cell.Water will leave the cell and the cell shrinks and shrivels. A practical example of this is when you use saline nose spray. The saline (salt) content is higher outside the nose cells which means lower water. Water leaves the cells. This helps to remove excess water from a runny nose!! Your have experienced a hypotonic solution when you eat something with a lot of salt. Your fingers swell; the salt enters your cells; there is more salt inside the cell, which means less water, the Water moves into the cell, causing a swelling, our body has mechanisms to prevent the cells from bursting. Can you figure out more examples??
Plant CellsPlant cells will live but not thrive in isotonic solution, plants do better withan increase in turgor pressure which results from a full vacuole.Hypertonic solutions existwhen plants are in very dry environments and there is more water inside the cellsthen in the atmosphere – water will leave the cells and go into the environment. The plant’s leaves may wilt. Plant plants prefer hypotonic solutions when the pressure in the central vacuole is high, the plant is able to retain it’s shape well. Often business place lettuce and spinach in distilled water to create the appearance of fresh plump vegetables .
So what did you learn?
• Compare and contrast the basic mechanisms of passive and active transport across the cell membrane.
• Describe osmosis and diffusion.
• To show complete mastery of the subject and a great way to earn bonus points, design a lab that will demonstrate osmosis, diffusion or both.
Answer the following and submit to the teacher for a grade.
References
Active Transport Image from http://school.discovery.com/quizzes13/zagzoo/CellSFTrans.html , Retrieved May 20, 2007
Animal Cell & Plant Cell Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com), Retrieved May 20, 2007
Egg Image from http://www.exploratorium.edu/cooking/eggs/images/naked2.jpg Retrieved May 14, 2007
Tomei, L (2001). Teaching Digitally: A Guide for Integrating Technology into the Classroom. Norwood, MA: Christopher-Gordon Publishers.
W.H. Freeman, (2007). Cellular Transport Images and Questions. www.whfreeman.com Retrieved May 20, 2007
W.H. Freeman, (2007). Animated Tutorial Active Transport from http://bcs.whfreeman.com/thelifewire/content/chp05/0502002.html, Retrieved May 27, 2007
W.H. Freeman, (2007). Animated Tutorial Passive Transport from http://bcs.whfreeman.com/thelifewire/content/chp05/0502001.html, Retrieved May 27, 2007
