Plant vs Animal A Cellular Comparison

Plant and animal cells have many structures in common as well as some basic differences. Plant cells have a rigid cell wall and if they are green they have chloroplasts. Animal cells lack both a cell wall and chloroplasts. They also lack a central vacuole that exists in plant cells.

Objective In this lab you will observe and note the differences and similarities between animal and plant cells.

Epithelial Cheek Cells You will first examine epithelial cells from the inside of your cheek. Epithelium is a type of tissue that covers the surface of organs and cavities of the body, as well as your skin.

Elodea Leaf Cells You will also look at cells from a leaf of the plant Elodea. The cells of this plant are green because they contain the pigment, chlorophyll. This is a pigment found in chloroplasts and allows a plant to absorb sunlight and manufacture its own food by the process of photosynthesis.

Materials Microscope Slides Cover slips Toothpick Pipette Elodea Forceps Lugol’s iodine solution Methylene blue stain

PROCEDURE PART I Human Cheek Cell

Obtain epithelial cells by gently scraping the inside of your cheek (in your mouth) with a clean toothpick. It may not look like there is anything on the tip of the toothpick when you are through, but there are microscopic skin cells. Stir the material from the toothpick in a drop of water on a clean slide. Throw the toothpick away when you are through. Add a small drop of methylene blue stain to the slide. Carefully place a cover slip on the slide. Examine the slide under low power. When you find some cells that are separate from each other, examine them under high power.

PROCEDURE PART II Elodea Leaf Cell

Break off a small leaf near the tip of an elodea plant. With forceps, place the entire leaf in a drop of water on a clean slide Add a cover slip Examine the leaf under low power. TAKE A PICTURE USING YOUR CAMERA To see the chloroplasts move, warm up the slide under a bright lamp for a few minutes.

Look for an area in the leaf where you can see the cells most clearly. Examine these cells under high power. TAKE A PICTURE USING YOUR CAMERA

Stained Elodea Leaf Break off another elodea leaf and place it in a drop of Lugol’s iodine solution on a clean slide. Add a cover slip.

TAKE A PICTURE USING YOUR CAMERA Answer the Analysis Questions