BIO 120 Grossmont College Experiment 5 The Microscope & the Cell Questions

Need help with my Biology question – I’m studying for my class.

Note: Here are the questions and there is a filed attached below to look at and answer these questions based on the PDF file I have provided.

Question 4. Now, write the generalized equation for the calculation of the total magnification. Your equation should use words, not numbers.

Question 5. Click on the shadowy e and drag it down toward the bottom of the circle (known as the Field of View or FOV), which direction does the stage move? Look at the slide mounted on the microscope while you are doing this.

Question 6. What happens to the stage when you click and drag the e to the top of the FOV?

Question 7. The virtual person who placed this e on the stage, placed it so that the slide label is facing upward and able to be read. However, how does the e look through the FOV?

Question 8. Slide the Course Focus Adjustment knob to the right until the letter e is clear. Then move the Fine Focus slider until it is even clearer. What happens to the amount of light?

Question 9. What do you have to do as you move from a lower magnification objective to a higher one? On a real microscope, would you open or close the iris diaphragm?

Question10. What is the low to high rule? Look for the answers to these in the video: Microscope Basics

Question 11. Why can you see only part of an image? An alternative way of looking at this is: why does a dark moon appears on one side? Look for the answers to these in the video: Common Microscope

Question 12. Why can’t I find the same part of the specimen once I move to a higher magnification? Look for the answers to these in the video: Common Microscope Mistakes:

Question 13. What is the FOV (in millimeters) at low-power of your microscope? Write the units (mm) after the number.

FOVlow = _______ mm

Question 14. How many microns are there in one millimeter? (Hint: which is smaller, micron or millimeter? Therefore, there would be many __________ in one __________.)

1 mm = ______ µm

Question 15. What is the FOV at low power in microns?

FOVlow = _____ µm

Question 16. Calculate the FOV of the high power field in microns (µm). Show your work.

Question 17. Convert the diameter of your field of view you just calculated for high magnification (answer in the previous question) into millimeters.

Question 18. How did the FOV change when you moved from low power to high power?

Question 19. Is the relationship between magnification and FOV direct or inverse? Explain.

Question 20. Describe how these terms are related:

Question 21. Cheek cells have been described as having a modified “fried egg” shape: flat except for the small lump at the nucleus. Can you tell that the cells are flat? Look for cells overlapping one another. Also, the edges of some cells may be “folded” back. Draw a few cheek cells, and label the cell membrane, nucleus and cytoplasm for one of them. (You may need to look these parts up in your textbook.)

Question 22. Recall the calculation for the FOV at high power. Estimate the size of a single cheek cell (at its widest point). One way to look at this is to estimate how many of these cells it would take to cross the entire diameter of the field of light. Then divide the FOV by the number of cells. Assume in the youtube video that you are seeing the entire FOV.

Width of single cheek cell = FOVhigh . = ______ µm

Number of cells across diameter

= _______________________ = ______µm

Question 23. Onion cells (and plant cells, in general) look a bit more like a brick wall. The cells may overlapping one another, depending on whether you accidentally folded the membrane peel. Draw a several onion cells, and label the cell wall, cell membrane, nucleus and cytoplasm for one of them. (You may need to look these parts up in your textbook.)

Question 24. Why do you think that the onion cell appears blocky, rather than rounded like the animal cell?

Question 25. Why do you think there is no evidence of chloroplasts in these onion plant cells? (Hint: Where does an onion with these types of leaves grow: above or below ground? Think about when you leave an onion on your kitchen counter after a while. What happens?)

Question 26. Recall the calculation for the FOV at high power in a previous question. Estimate the size of a single onion cell (along its longest edge).

Length of single onion = FOV . = ___________µm

Number of cells across diameter

= = ___________µm

Question 27. Draw a Paramecium, showing any visible internal structures. Label cell membrane. You may or may not see evidence of the cilia on the cell membrane. Label where the cilia would be.

Question 28. Can you see movement inside the Paramecium? Does there appear to be a single location where the yeasts enter the cell? This is called the oral groove. Label this on the drawing you did for the question above.

Question 29. The Congo Red dye changes from red to blue color when the solution is quite acidic (pH less than 3). Is there any evidence of color change as the yeast cells are consumed?

Question 30. Consider what a plant needs to grow and how different substances are moved from one part of a plant to another. List 3 key factors that a plant needs to grow.

Question 31. Above is a diagram showing the orientation of the cross section and the longitudinal section as the slices were made from the very young corn plant. Draw a few of the red cells as they appear in each section. Label the red and green cells as the vascular bundles.

(a) longitudinal section: (b) cross section:

Question 32. Which of these 3 factors you listed in Question 30 are the vascular bundle cells you observed involved? (If you are not sure, read in your textbook!)

Question 33. Describe what you think is the function of the cell you have drawn above, and explain how the cell’s shape (structure) helps with its function.

Question 34. Draw one adipose cell. On your drawing, label the nucleus, cell membrane, and the area where fat is stored.

Question 35. Remember that adipose cells are spheres and you are only observing two dimensions. Because the adipose tissue on the slide has been sliced very thin, the cell you drew in Question 34 may only be a slice across the middle of the whole cell. Imagine a slice from a tomato. Now imagine how your diagram relates to the entire cell and try to draw the whole cell below.

Question 36. The adipose cell is a beautiful example of structure and function. Its structure is basically a sphere, which of all possible shapes gives the maximum volume for the amount of surface material used (cell membrane). Describe how this feature makes the cell well-suited for its function.

Question 37. Draw one cell with cilia:

Question 38. Epithelial tissues are generally those which cover and protect other tissues. Ciliated epithelial cells are found on inside surfaces of certain tubes in the body, such as the respiratory airways and the oviducts. In these locations, ciliated cells are specialized for moving fluids.

  1. In the respiratory tract, cilia “beat” in a coordinated manner toward the mouth. Suggest a valuable result of this behavior.
  2. In the oviduct, cilia “beat” in the direction of the uterus. Describe how this behavior could help reproduction. (Look up the function of the oviduct if this puzzles you.)

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