Laboratory one: Introduction to Microscopy

LABORATORY ONE: INTRODUCTION TO MICROSCOPY

Ang, Elaine

Ceperiano, Arjohn

Dizon, Juan Paulo

Galbraith, Natasha Allen

Lim, Fenina Joyce

Ng, Mary Cathlyn

Ongsiyping, Janelle

Santos, Emmanuel

Ty, Michelle Jenine

Ateneo de Manila University

Loyola Heights Campus Katipunan Avenue, Loyola Heights, Quezon City 1108, Philippines

Key words. Calibration, compound light microscope, magnification, monocot root.

Abstract

This lab activity aims to provide us a comprehensive familiarity with the proper use and handling of the optical microscope, which is a significant instrument in viewing, inspecting and studying the different parts, structures, and components of various botanical specimens.

In this particular experiment, we will study the cross section of a monocot root. In the process, we will become familiar with the parts of the monocot root such as the stele, the central part of the root, and other main internal structures that are found within it such as the metaxylem and protoxylem. (Gifford and Foster 1988)

The main part of the activity is identifying the microscope’s calibration. We will be able to perform such by first determining the ocular micrometer constant from the stage micrometer and ocular micrometer. By determining the ocular micrometer constant, the objective lens constant can be known from the product of the ocular micrometer constant and the eyepiece magnification. The magnification of the illustration can be derived using the monocot root slide. Finally, when these constants are obtained, the magnification of the drawing is obtained.

After calibration and computations, the following findings have been derived:

Ocular micrometer constant 0.01 mm

Objective lens calibration 1 mm

Size of metaxylem 11 ocular units

Magnification:

1.3 cm / 30 mm = 330x magnification

2.5 cm / 50 mm = 550x magnification

I. Introduction

The current trend of technology is that the smaller the product the better; hence, every month companies compete with each other and releases multiple gadgets, besting one another in terms of size and product specifications.

There is a new branch of Science which deals with minute entities where interests from all parts of the world have been emerging: Nanotechnology. It is said to have caused a number of controversies (HernÐ"ÐŽndez 2004) and disagreements from scientists (Center for Responsible Nanotechnology c2008) but despite these, the field continues to move forward with each and every discovery. As freshmen, our concentration will lie not with Nanotechnology but another branch of Science that needs us to depend on tools in order to do our assigned tasks: Microscopy.

Ever since the invention of the compound microscope during 1590 by Zacharias Janssen and the discovery of cells by Robert Hooke in 1665 (MicrosoftÐ'® Student Encarta 2008), it conceptualized a new field of study that allows us to inquire further about life. Because the structural unit of life is cells, cellular study is essential in any area of biological study (Velasquez, Asis 1993). Furthermore, since cells are tiny units, they can only be observed under a microscope. Many have acquired the use of the microscope as a research tool to reveal cellular structure and to explore the properties and functions of the cells.

Hence, as students taking the course for the deeper understanding of plants, we must acquire the skills and knowledge to operate a compound light microscope and successfully compute the magnification of the illustration as seen through the microscope. Moreover we aim to learn how to correctly calibrate the microscope through the use of stage and ocular lens; identify the microscopic parts of a monocot root and properly handle the materials needed for this laboratory experiment.

This laboratory experience is an introduction to us as Filipino students on the change we can bring to our country through the knowledge that will be granted to us by the Lord. Through this endeavour, we hope to discover values that will fortify our determination and zeal in seeking and to improve the state of our country, and grow into persons who will dedicate their time patiently on discovering new interests beneficial to the community.

II. Methodology

A. Materials

1.Number 22 - Olympus compound light microscope model CH1OMOF number 0G17839 (see MicroscopeNumber.jpg and OlympusModel.jpg)

2.Number 15 ocular lens micrometer (see OcularScanner.jpg)

3.Number 27 stage micrometer

4.Slide box number B261

5.Monocot root slide 261-8 (see MonocotRootSlide.jpg)

B. Procedure

1.We obtained an optical microscope, Olympus CH1OMOF number 0G17839, from the laboratory, which we would use to identify our micrometer calibration.

2.We then placed the #15 ocular lens micrometer on the eyepiece lens of the microscope. When looking into the microscope, we ensured that the #27 stage micrometer was positioned slightly on top of the ocular micrometer.

3.Afterwards, we identified the starting number (or zero) by detecting the point in which the ocular micrometer’s lines and stage micrometer’s lines perfectly overlapped.

4.Then, we determined the next point in which the ocular micrometer’s lines and stage micrometer’s lines perfectly overlapped.

5.We counted the number of stage micrometer units between the first and second meeting points. We did the same, too, for the ocular micrometer.

6.To determine the ocular micrometer constant, we divided the number of stage micrometer units we previously counted by the counted number of ocular micrometer units and multiplied it with a value of 0.01 mm.

7.After, we obtained the objective

...