BY1.01, BY2.02

Banana Cell Diagram

Purpose: To use a compound microscope to observe visible structures in a banana cell.

Hypothesis:

Materials:Compound microscopeToothpick

Glass slidePiece of banana

Cover slipIodine

Procedure:

  1. Carefully carry a compound microscope to your station.
  2. Take your glass slide and prepare a wet mount of a tiny piece of banana. It is important that you get as thin a layer as possible.

Wet Mount

Place a thin layer of banana on your glass slide. Make sure the glass slide is clean.

Add a drop of iodine to your banana smear.

Holding a cover slip by the edges, lower it until one edge makes complete contact with the slide.

Slowly lower the cover slip so that no air bubbles form.

  1. Place your slide on the microscope. Remember to adjust the coarse focus (the big knob) before the fine focus.
  2. Look for an area with cell spread out. Try to avoid areas with clumped or overlapping cells.
  3. Draw what you see below.

Low PowerMedium Power

“Field of View”

  1. Using a blank piece of paper draw a cell under high power. Use something with a round bottom to make the field of view.
  2. Label all the structures you can see.
  3. Do not shade, stipple (tiny dots) with your pencil areas that are darker than others.
  4. All lines should be parallel to each other, none should cross and ALL should be drawn with a RULER.
  5. Calculate the magnification of your drawing.

Magnification

You can obtain the magnification of your drawing by taking the magnification of the ocular lens (10x) and multiplying it by the magnification of the objective lens you are using.

Example: Using the low power objective lens.

(10X) ocular x (4X) = 40 X

Therefore the magnification is 40 X. You must write this under your diagram.

  1. Clean-Up.

Please put away your microscope, remembering to put the cover on. Always make sure to put the objective lens on low power before putting it away.

Rinse your slide and cover slip in the sink and put them to dry on a paper towel. These can be reused.