Corn Kernel Dissection

Corn Kernel Dissection

Student lab

Pre-Lab Day:

Steeping the Corn Kernels:

Place enough corn kernels in a beaker with tap water so that each person/group has at least one nice sized seed. Place the beaker in a water bath or another container (double boiler style) with 50⁰C water for 24 hours. Corn can be obtained from local stores that sell ear corn for animal/bird feed.

Materials for each group/person:

Corn kernels

Small paper plate (6 ¼ in. diameter)

A piece of paper and pencil/pen to record results

Dissecting needle, push pin or large T-pin

Paper towel

Forceps (optional)

Label the major parts of the corn kernel:

Label the parts of the corn kernel shown in diagram 1. This will help you locate the parts (anatomy) of the corn kernels for lab dissection. You will need to use the search tools available to you to research the labels for the diagram.

Diagram 1

Lab Day

1. 
   Place a kernel of corn on the paper plate and label different areas on the plate to correspond to the five distinct areas of the kernel from diagram 1: tip cap, pericarp (hull), germ, floury endosperm (white colored) and horny endosperm (yellow colored).
   

2. 
   Remove the tip cap of the kernel and place it on the section of the plate labeled “tip cap.”
   

3. 
   Remove as much of the two layers of hull called pericarp as you can and place it on the section marked “pericarp.”
   

4. 
   Locate and remove the germ part of the kernel. Place it on the section of the plate labeled “germ.”
   

5. 
   What remains is the endosperm. The endosperm has two parts; floury endosperm (white part) and the horny endosperm (yellow part).
   

6. 
   Separate the two endosperms and place them on their corresponding sections of the plate.
   

7. 
   Estimate, using percentages, the approximate part of the total kernel that each kernel component represents. If a 0.01 g accuracy scale is available, mass the kernel’s components. With a less accurate scale, have each group do multiple kernels or have several groups combine their kernel components.
   

8. 
   To demonstrate the oil content in the germ, crush the germ component of the kernel on a paper towel using a blunt instrument. Let it sit overnight and observe the amount of oil stain left on the towel.
   

9. 
   Construct a chart showing your results and comparing them with the actual accepted/established amount (%) for each part of the kernel.
   

Questions:

10. 
    Research the commercial products that are made from each part of the kernel.
    

11. 
    One bushel of shelled corn weighs 56 lbs.
    
    1. 
       How many kernels of corn are in a bushel?
       
    2. 
       Using your results, determine the mass (lbs and kg) of each of the kernel’s five components in one bushel of corn.
       

12. 
    What part(s) of the corn kernel is/are used to make biofuels?
    

13. 
    How is the process “steeping” used commercially?
    

Your teacher may have additional problems/questions/discussion to complete. (Refer to problems bank, teacher section.)

Enhancement

Additional questions or problems: