Report of Spectro

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MOLECULER BIOLOGY AND GENETICS DEPARTMENTS

BIO112E-GENERAL BIOLOGY 2

INTRODUCTION LIGHT MICROSCOPY&LIGHT MICROSCOPY-II

DATE OF EXPERIMENT                       : 12.04.2016-26.04.2016

DATE OF THE DELIVERED REPORT : 03.05.2016

NUMBER OF GROUP………………… : 3(A.F. AYAŞ, Ö. KARA, S. BİLGİÇ, M. C ÇATAK, B.ERSU, A.ARSLANGÜNDOĞDU

NAME OF WRİTTEN REPORT              : AHMET FATİH AYAŞ(090130014)

LECTURER………………………………: AR. GÖR. DR. DENİZ ŞAHİN

ABSTRACT

Aim of first experiment is learning using light microscopy, learning parts of the microscopy and their function, learning type of microscopy, practising using microscope skill, using various objective for magnification and observe magnification area, observe prokaryotic and eukaryotic sample. Also, learning effect of immersion oil under the total magnification of 1000X.

Aim of second experiment is learning prepare plant sample, animal sample in wet mounts, and blood sample, identify organism and analysed their structure. Also, learn to identify hypertonic, isotonic and hypotonic solution with observing microscopy.

Both of these experiment learn to draw structure, identify organism and difference of organisim.

INTRODUCTION

History of microscope

         Hans Lippershey and his son Zaccharias Hanssen was experimenting type of lenses in a tube in the late 1590’s and they were surprised to see object. Because object was so magnified. So, they invented compound microscope. Then, Robert Hooke and Anthony Van Leeuwenhoek took the microscope new levels. Robert Hook invented iris diaphragm which is component of many modern light microscope. Hooke work  on theory of combustion , invented to describe equation elasticity that called ‘Hooke’s Law’ and their provide develope meteorological instruments like barometer, anemometer etc. Also Hooke is known for ‘micrographia which became an overnight sensation. He describe honeycomb structure or ‘cells’ of a cork.

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Antonie van Leeuwenhoek is known the inventer of microscope. He drew on Hooke’s work to take microscope design to more new sophistication level. He developed lenses for improve optical quality. He ground 550 lenses. He created simple microscope could magnify to about 275X. Also, he had discovered bacteria, parasitic microscopic protists, sperm cells, blood cells, and microscopic nematodes. After the 100 years, Charles Hall invented achromatic lens in the 1730’s. Also he discovered second lens of different shape and refracting properties. Carl Zeiss recruited Ernst Abbe as director of research at the Zeiss Optical Works. Abbe revealed outline about modern computational optics development approach. He explained difference bettween magnification, resolution and criticized practice of using eyepieces with too high a magnification as ‘empty magnification’.

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Abbe’s work on a wave theory of microscopic imaging. He made improved new range of 17 microscope objectives and 3 of his objectives were the first immersion objectives and he design based on mathematical modelling.

Mass market for microscope improved same time improving engineering. In 1879, Walter Flemming discovered cell mitosis and chromosomes.

By 1900, theoretic limit of resolution had been reached for visible light microscopes. In 1904, Zeiss produced UV microscope with resolution twice of visible light microscope. In 1931, Max Knoll and Ernst Ruska invented electron microscope. Physics dictates that light microscopes are limited by physics of light to magnification of 500X or 1000X  and resolution of 0.2 micrometers.  

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Knoll and Ruska done transmission electron microscope(TEM) which transmits a beaö of electrons through the specimen. In 1942, Ruska developed TEM and built scanning electron microscope(SEM) which transmits beam of electron across the specimen.(1)

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Types of Light Microscope

The most commen are used bright-field, phase contrast and dark-field microscope.

Bright Field microscopy provide that liht from ancandescent source is aimed toward a lens benath the stage, through the specimen, through objective lens, through second magnifying lens, the eyepiece. Objects can be seen with light because natural pigmentation absorb differently. Microscope built in illuminator, adjustable condenserwith diaphragm(contrast) control, adjustable stage and eyepiece tube. Condenser provide focus light.(2)

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Phase Contrast Microscope

Phase Contrast Microscope is çömmen used for examining like specimen as biological tissues. It enhances contrast of transparent and colorless objects by affecting the optical way of light.

Altering the Light waves: phase contrast microscope uses light passing through specimen goes slower and because of this is relocated compared to the uneffected light. Human eye cannot see this phase. But the change in phase can be increased to half wavelength by phase-plate in the microscope and thereby reason a difference in brightness.(3)

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Dark-Field microscope

Dark-Field microscope Works a hollow and so intense cone of light concentrated on the specimen. Reaching lights to lens is distracted by specimen. This technic produce classic appearance of dark background.(4)

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Theory of Light Microscope

Light microscope involve three basic concept: magnification, resolving power and contrast.

Magnification is provide to see object as larger. Magnification consist of two lens system. One of them is an ocular lens or eyepiece is found top of the microscope and it usuallay is 8X or 10X. Other part is objective lens. Objective lens is found above stage and it usually is 4X, 10X and 40X. Total magnification is calculated objective lens X eyepiece lens. For example, objective lens= 40X and eyepice lens=10X, total magnification will be 40X*10X=400X.

Contrast provide to see special detail in the specimen. The most common way for increase contrast is dye like etylen blue. (5)

Resolving power provide measure the seperation of so close image together. If two points are closer together than your resolution, they appearn bad defined and positions will be incorrect. (6)

Some Compounds of Light Microscope

Stage: is metallic platform at central hole and  it hold specimen.

Body tube: is found between eyespiece and objective lens way.

Diaphragm: is flitted below stage for regulating amount of light failing on the object.