Part of Unit: Mathematical and Scientific Concepts
Lesson Plan Overview / Details
One of the main challenges in biotech is that we are often working with things that are too small for our eyes to see. This activity will help students put into perspective the relative sizes between all the major microscopic structures inherent in biotechnology.
For example, we can easily understand the difference in height between a 25-story building and an 11-inch piece of paper, but did you know this is the same relative size difference between a skin cell and an influenza virus? Your student's probably don't!
- 90 Minutes
California Career and Technical Education Standards
- HSMT.A.A2.3 Know the basic structures and functions of cells and how this knowledge is used ...
- HSMT.FS.5.3 Use critical thinking skills to make informed decisions and solve problems.
California Academic Content Standards (Reinforced)
- ELA.9-10.R.CAGT.2.4 Synthesize the content from several sources or works by a single author dealing ...32
- S.9-12.LS.1.c Students know how prokaryotic cells, eukaryotic cells (including those from plan...1
Common Core Standards (Reinforced)
Objectives and Goals
- Engage terminology and definitions associated with basic cellular structures
- Develop a comprehension and comparison point between relative sizes of microscopic structures
- Develop a general understanding of the roles played by various cellular parts
- and other stuff
Activities in this Lesson
- Worlds We Don't See - Hooks / Set
Just to get students looking at and considering elements of a world that went unknown and unidentified until Robert Hooke's examination of a slice of cork, I ask students to watch the following two videos and simply record in their notes, what they believe they are observing in general detail.
I like to begin with the Harvard BioVision video entitled Inner Life- Minute Music Version and then if time permits, show the Inner Life -Super Speed Version towards the end of the lesson to give students a bearing point for what they are observing. (At the end of the lesson, they will have some further context for the video as well...won't seem so "alien")
The second video you might show as a beginning point either with the above selection or on its own is one of the classic Zoom from Atom to Universe type videos. You can find many of these online, but this one actually annotates the items being observed in much the same fashion as our following activities within this lesson. You pick what works best for you and your students!
- Harvard BioVisions Collection [ Go to Site ] Very well produced cellular level video animations. Some narrated, some set to music.
- Atom to Universe Progression [ Watch Video ] [ Download Original Video ] this is a video that shows relative sizes of objects from microscopic proportions to galactic structures.
- Zoom from Small to Large [ Go to Site ] same video as above, but linked to youtube with identifiers for each item.
- Sort Cards from Largest to Smallest - Independent Practice
Following the opening video segments, provide each student a set of cards (see attached for printing out in advance). Ask them to put the cards in order by size as best they can. I like to give them about 5 miutes to skim through them and begin to lay them out in order as best they can across their own desks. I instruct students that it is important that they at least attempt to place them in order now, and that we can modify their orders as we proceed through the lesson today. Here is a list of the items that are present on their cards which is a printed resource from the University of Utah's Genetic Science Learning Center Collection.
Coffee Bean, Grain of Salt, Amoeba Proteus, Human Egg Cell, Paramecium, Skin Cell, Sperm Cell, Red Blood Cell, Baker’s Yeast, Mitochondria, E. Coli Bacterium, Influenza Virus, Ribosome, Antibody, Phospholipid, Adenine, Glucose, Carbon Atom
- Relative Sizes Cards [ Download ] Print out one set per student. Cut them out and paperclip each set of cards.
- Review of Terminology - Lecture
Many of the items on the cards should be somewhat familiar to the students. However, most students will not remember every term. Use the attached powerpoint presentation to review and answer any questions.
Other interesting things to include in your lecture...
Compare Small Objects to Larger Objects
If a carbon atom = 7 pixels, then
Antibody = 1 inch
Influenza virus = 8.5 inch x 11 inch piece of paper
Mitochondrion = 8 foot x 30 foot (classroom wall)
Skin Cell = a 25-floor building
Explian How We Can See Small Objects
The smallest objects that the unaided HUMAN EYE can see are about 0.1 mm long. That means that under the right conditions, you might be able to see an ameoba proteus, a human egg, and a paramecium without using magnification. A magnifying glass can help you to see them more clearly, but they will still look tiny.
Smaller cells are easily visible under a LIGHT MICROSCOPE. It's even possible to make out structures within the cell, such as the nucleus, mitochondria and chloroplasts. Light microscopes use a system of lenses to magnify an image. The power of a light microscope is limited by the wavelength of visible light, which is about 500 nm (nanometers). The most powerful light microscopes can resolve bacteria but not viruses.
Going Nano! To see anything smaller than 500 nm, you will need an ELECTRON MICROSCOPE. Electron microscopes shoot a high-voltage beam of electrons onto or through an object, which deflects and absorbs some of the electrons. Resolution is still limited by the wavelength of the electron beam, but this wavelength is much smaller than that of visible light. The most powerful electron microscopes can resolve molecules and even individual atoms. To better understand Nano Scale, watch the video linked below and answer the questions at the end.
- Relative Sizes on a Cellular Level - Demo / Modeling
Have students go to the following website: http://learn.genetics.utah.edu/content/begin/cells/scale/ (linked below).
Those students who have yet to fully organize their cards in progressive order of size of elements found on a visual to cellular to molecular level, can zoom through the images, from a coffee bean to a carbon atom and everything in between in relation to the items found in their deck.
This is in turn a great visualization tool to help them appreciate relative sizes. Ask them to use the website to finish putting their cards in order correctly (if they have not done so already!) If students do not have access to their own laptops or computers, you can simply demonstrate the zoom in and out feature for them as projected on a screen. I suggest you consider starting with the image zoomed all the way down to the Carbon Atom and zooming out to the begin point with the Coffee Bean.
- Interactive Cell Size and Scale [ Go to Site ] A nice Flash-based presentation of the relativity of various sizes of very small objects: from coffee beans, grains of salt and rice, down to HIV, antibodies, water molecules, carbon atoms and elements of a cell.
- Documentation and Further Cell Discovery - Closure
Provide tape or glue and ask students to attach their cards in order to their notebooks. Have them write a short paragraph about what they were surprised to learn about relative sizes. When they are finished, they are to come to you so that you may check their notebooks.
As an extension activity or a pre-learning exploration, direct students to the Amazing Cells site and go through the “inside a cell” activity as a precursor to the information they will be encountering in upcoming lessons on Cell organelles and structures and their functions.
- Amazing Cells [ Go to Site ] Explore the cell's interior, parts of the cell, and how cells communicate through this interactive view into an animal cell
- Assessment Types:
Check their notebook for the correct order of the cards and completion of the paragraph about what they learned. Stamp or check off thier notebook and record their credit, dont forget to include any extra credit for those students who were able to correctly identify the size sequence in the first or second activity if you deem it more than a "lucky guess."
As a nice extension assessment, you could have students take into account the relational comparison between a skin cell and an influenza virus shared at the beginning of this lesson (25 story building to and 11 inch piece of paper respectively) and the other comparisons provided in this lesson plan. Have them formulate the difference in scale amongst these two items and then have them create a simliar scale comparison using common visible objects when the smaller of the two objects is 2 inches or less. For instance, a paperclip or an eraser head or a grain of rice instead of a sheet of paper. It is interesting to see the comparative objects students will generate, and you can also assess their overall understanding of relative sizes as well as proportional reasoning. For advanced students have them create compartive elements for other items from their cards such as the carbon atom and a red blood cell...