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Virtual Lab – Operation of Bright Field Microscope How do you calculate total magnification for a compound light microscope?

Virtual Lab – Operation of Bright Field Microscope When using the 100X objective lens, a drop of water is needed on the specimen slide. 

Virtual Lab – Label the Parts and Describe the Function of the Parts of the Microscope Directions: Use the word bank to complete the table below by matching each microscope part to its corresponding number.  Mechanical Stage Rotating Nosepiece Fine Focus Knob Objective lens Coarse Focus Knob Oculars Condenser Stage adjustment knobs Iris Diaphragm Light source       1. [part1] 6. [part6] 2. [part2] 7. [part7] 3. [part3] 8. [part8] 4. [part4] 9. [part9] 5. [part5] 10. [part10]          

Virtual Lab – Microscopy – Plant Cells (Onion Epidermal Cells) What did you notice happened with the microscope image as you increased magnification?

Virtual Lab – Microscopy – Wet Mount (Euglena) What is the eyespot for in the Euglena?

Virtual Lab – Microscopy – Animal Cells (Human Epidermal Cells) If you were given a slide of cells from an unknown organism, you could determine whether the cells are from a plant or an animal by looking for the cell wall, chloroplasts, and a vacuole.

Virtual Lab – Microscopy – Animal Cells (Human Epidermal Cells) Why was a stain added to the human epidermal cells from the cheek smear prior to microscopic observation?

Virtual Lab – Microscopy – Animal Cells (Human Epidermal Cells) What was the general shape of the cheek cell? How is that different from the onion cells you observed from the last simulation?

Dialysis tubing is a selectively permeable membrane made with the macromolecule, cellulose. Starch, glucose, water and the IKI reagent arecontained within the dialysis membrane in solution B shown below. Solution A in the beaker, at the start of the experiment in panel (a) contains just water. Diffusion of these molecules occurs, over time, from panels (a)-(c). The only selective criterion for diffusion across a dialysis membrane is the size of the molecule.   Do you think the solution volume inside the dialysis tubing (B) will increase or decrease based on the direction of molecule movement (the actual volume in panel (C) does not appear to change because the volume change is small)? Why? The solution volume inside the dialysis tubing (B) will likely increase. Here’s why: Osmosis and Selective Permeability: The dialysis tubing acts as a selectively permeable membrane, allowing small molecules like water and glucose to pass through but not larger molecules like starch. Concentration Gradient: Initially, the concentration of water outside the tubing (in the beaker) is higher compared to the inside, where there is a mixture of water, glucose, and starch. As water molecules move from an area of higher concentration (outside the tubing) to an area of lower concentration (inside the tubing), osmosis occurs. Movement of Water: As water moves into the tubing (B) to balance the concentration of solutes, the volume of the solution inside the tubing increases. So, even though the change in volume might be small and not easily observed in the diagram (panel C), the direction of water movement suggests an increase in volume inside the tubing.

Virtual Lab – Microscopy – Wet Mount (Euglena) What similarities and differences do you see between the plant cells (onion and Elodea) and the Euglena? Similarities: All three types of cells (onion, Elodea, and Euglena) contain a cell membrane, cytoplasm, and a nucleus. They have chloroplasts (Elodea and Euglena) or can contain pigments involved in photosynthesis. Differences: Onion Cells: Onion cells are typically rectangular and lack chloroplasts as they are not photosynthetic. They have a large central vacuole and a rigid cell wall. Elodea Cells: Elodea cells are rectangular or box-like and contain chloroplasts for photosynthesis. They have a cell wall and a central vacuole. Euglena: Euglena is unicellular and has a flexible outer membrane called a pellicle rather than a rigid cell wall. It has chloroplasts for photosynthesis but also can consume food from the environment. Euglena also features a flagellum for movement.