Light microscopy, Biology

Assignment Help:

Light microscopy:

Microscopy started with light microscopes using visible light to illuminate the objects, the most used and familiar microscope is called compound light microscope. Its simplest form it consists of two optical lenses, one at each of a hollow tube. The lens closer to the object is called objective and the one closer to the observer eyes is called eyepiece. The object, mounted upon a glass slide, which  is put upon a centrally perforated satge  under the objective, is illuminated by light , a mirror is fitted below the stage to focus light on  to the object, a third lens system ,called  condenser may be fitted between the mirror and the stage to concentrate the light. The limit of the resolving power of best compound light microscopes is about 0.2 achieving a magnification of about 2000 times the size of the objects. Thus these microscopes can resolve even most of the bacteria, but they cannot reveal   the internal details of bacterial cells.

Use of ground glasses as optical lenses to magnify objects was presumably realized several centuries ago. The first name on record is of Conrad Gesner who used magnifying lenses to observe certain foraminifera's. Next Zacharias Janssen (Dutch 1590) constructed, together with his father, Hans Janssen the first compound light microscope to study insects which  could magnify objects 10 to 30 times. Galileo constructed microscope with greater magnifying powers and studied the arrangement of facets in the compound eyes of insects. Marcello Malpighi (1628-1694)  microscopically studied animal and plant tissues in  thin slices of several organs, earning the  title of the father of microscopic anatomy,  Robert Hooke (English 1665)  designed a compound light microscope  either a magnifying power of about 42 times and studied amongst other  object thin slice  of cork  discovering cells. Antony van Leeuwenhoek  (Dutch 1676)  designed single lens microscopes with magnifications approaching   300 times and become the first to observe sperms, blood cells muscle fibres, lenses of eyes,  hydrae yeast cells and microscopic organisms in water like bacteria, protozoan's  rotifers tec. Earning the little of the father of microbiology so commonly used these days by students in schools and collages all over the world , was developed from Hooke  model by Wilson (1970).

Zigmondy (1900) designed an ultra microscope using ultraviolet rays in place of ordinary light and quartz lenses in place of ordinary glass lenses, achieving a resolving power of0.1 and magnification of about 4000 times.


Related Discussions:- Light microscopy

importance of water in the body, Importance of water in the body Wa...

Importance of water in the body Water is the most essential constituent of life. Life cannot exist without water. About 90% of water is present in protoplasm  Water

What is technetium 99m sestamibi scan, Q. What is Technetium 99M Sestamibi ...

Q. What is Technetium 99M Sestamibi Scan? This study is another form of studying perfusion of the heart. This radioactive study is similar to that of thallium 201. With a combi

Define types of circulatory systems, Q. What are the two kinds of circulat...

Q. What are the two kinds of circulatory systems? The circulatory systems can be classified into closed circulatory system and open circulatory system.

Biological energy, Biological energy: Whenever matter is broken down its c...

Biological energy: Whenever matter is broken down its chemical energy is released as heat. Non biological system can utilize this heat energy directly in the performance  of work,

Habitat conservation - conservation of wildlife, Habitat Conservation - Con...

Habitat Conservation - Conservation of Wildlife Actually conservation means different things to different people. In the present context, conservation refers to the preservati

Suction force of the plant cell, What is meant by suction force of the plan...

What is meant by suction force of the plant cell? Does the suction force facilitate or make difficult the entrance of water in the cell? Ans) The suction force (SF) is the osmot

What is the importance of the glucose blood level, What is the importance o...

What is the importance of the glucose blood level for human health? The glucose blood level (glycemia) must be kept normal. If it is abnormally low there is not enough glucose

Do plants have tissue organization and specialized organs, Do plants have t...

Do plants have tissue organization and specialized organs? Plants have specialized organs (as reproductive organs, roots, limbs, leaves) and differentiated tissues (vascular t

Explain coronaw artery disease, Explain CORONAW ARTERY DISEASE (CAD)? A...

Explain CORONAW ARTERY DISEASE (CAD)? As far as CAD is concerned the people of South Asian region are at a very disadvantageous position. The term 'South Asians' includes perso

Primary producers - biotic components , Primary producers - Biotic Componen...

Primary producers - Biotic Components The major primary producers of aquatic ecosystems (freshwater and marine) are various species of algae. In terrestrial ecosystems the ma

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd