FOR WAGGONER’S BIOLOGY 
19 
EXERCISE 20 
CELL STRUCTURE 
I. Plant cells. Examine a bit of banana pulp which has been 
mounted under the microscope. Note the tiny oval structures. 
These are cells. Can you distinguish them with the naked eye? 
Why? Of what is the flesh of the banana composed? Stain the 
cells by adding a drop of iodine. What is the effect? What does 
this indicate with regard to these grains? Do you find a cell wall? 
A nucleus? Make drawings of several cells showing the parts which 
are visible to you. 
II. Animal Cells. Examine some cells from the inside of the 
cheek which have been mounted under the microscope. (These 
may be obtained by gently scraping the cheek lining with the 
finger nail.) What is the color of these? Is there a definite cell 
wall present? Do you find any starch grains? How do these cells 
differ from those of the banana? What is the transparent granular 
substance of which the cell is composed? Note whether there is a 
tiny, apparently more solid, portion near the center of each cell. 
If so you are seeing the nucleus. The protoplasm outside the 
nucleus is the cytoplasm. Draw several of the cheek cells. Show 
the parts which were observed in each. (See Waggoner, Fig. 51.) 
III. What marked characteristic of plant cells is not found in 
animal cells? What is a cell? 
EXERCISE 21 
CELL DIVISION — MITOSIS 
For this exercise use models, or lantern or microscopic slides. 
Refer to the diagram (Waggoner, Fig. 52). 
I. The Resting Stage. Locate the following structures: the 
cell wall (or membrane), the cytoplasm, the nucleus. In the 
nucleus, locate the chromatin particles. (In the models, you may 
