Laboratory #1: Introduction to Cells and Cell Structures

Unit 3 Lab

Today you will:

Observe plant, animal, protist and bacterial cells.

Be able to identify cellular structures (membrane, nucleus, etc)

Advice: Do not rush through this lab!

Materials:

Paper

Lab Report

Pen/Pencil

Microscope

Microscope Slides

Cover Slips

Elodea Leaves

Methylene Blue

Part I. Observations of Plant Cells

First, become familiar with the cellular structure of a leaf of Elodea, a water plant, by studying a prepared slide. The leaf has many layers of cells, especially in the thickest central part of the leaf. When many layers of cells overlap, the details of small structures within each cell become hidden. Therefore, it is most important for you to find cells near the edge of the leaf. Choose cells that are large and easy for you to observe clearly.

Make a hypothesis sketch what you think the plant cell will look like.

Procedure

Wet Mount: Get a leaf of living Elodea. Choose one of the youngest (smallest) leaves from a sprig of Elodea. Make sure that the leaf is bright green and has thin, almost see-through edges. Tear one leaf off the Elodea, tear it in half, and place it on a clean microscope slide. Add 1-2 drops of water to the leaf and place one cover glass on top of the leaf. BE CAREFUL, cover glasses tend to stick together. If you have two cover glasses stuck together you will not be able to use the 100x objective on your specimen.

Collect Data

Examine the wet mount slide of Elodea, first using the 4x, objective, then with the 10x, and then the 40x. Notice that there are many different layers of cells present.

At each level of the microscope (4x, 10x and 40x) make a drawing of 2 cells. Make sure to identify chloroplasts and cell walls.

Analyze the Data

Do the cells look like the plant cells that you see in the textbook? Why or why not?

Conclusions 

What is the benefit of being able to see the cells with higher magnification?

A....