Microbiology chapter 4. Microscopy, staining and classification Review for the e
ID: 202068 • Letter: M
Question
Microbiology chapter 4. Microscopy, staining and classificationReview for the exam. Please type for me and explain the concept and fact that I should prepare for the exam. Chapter 4 Chapter 4 CONCEPTS C4.1 3 General Principles of Microscopy which influence observation of microbes C4.2 To increase A) Magnification and B) Resolution use smaller wavelength of light C4.3 Light changes direction (refracts) when it moves from one medium to another C4.4 Magnification 50/5-10X C4.5 Compound Microscope features- multiple lenses Totall magnification Feb17 ar3 C4.6 Principles of Staining Simple Staining ar10 Differential Staining Basic dyes Acidic dyes r24 C4.10 Serological tests C4.12 Analysis of nucleic acids C4.13 Taxonomic Keys Dichotomous keys C4.14 Binomial nomenclature Microbe Naming Rules C4.15 Taxonomy consists of identification, nomenclature, and classification Why do Taxonomy ? Organize large amounts of information about organisms Make predictions based on knowledge of similar organisms C4.16 Goal of modern taxonomy is to reflect phylogenetic hierarchy Chapter 4 FACTS
Explanation / Answer
1.
Basic Principle of Microscopes-
A general biological microscope mainly consists of an objective lens, ocular lens, lens tube, stage, and reflector. An object placed on the stage is magnified through the objective lens. When the target is focused, a magnified image can be observed through the ocular lens.
Telescopes also have a similar structure; however, they are used for observing distant objects. A telescope receives light from a star or other distant object with the objective lens and adjusts the refracted light to the focal point through the ocular lens. On the other hand, a microscope is designed to emit light onto or through objects and magnify the transmitted or reflected light with the objective and ocular lenses.
2. A. Magnification -
Magnification is the process of enlarging the appearance, not physical size, of something. This enlargement is quantified by a calculated number also called "magnification". When this number is less than one, it refers to a reduction in size, sometimes called "minification" or "de-magnification".
Typically, magnification is related to scaling up visuals or images to be able to see more detail, increasing resolution, using microscope, printing techniques, or digital processing. In all cases, the magnification of the image does not change the perspective of the image.
B. Wavelength -
Things with long wavelengths are analogous to the basketball in the cave story because neither can provide too much detail about what they hit. Things with short wavelengths are like the marbles in that they can provide you with fairly detailed information about what they hit. The shorter the probe's wavelength is, the more information you can get about the target. That mean for clear observation we have to use the short wavelength.
3.Light is an electromagnetic wave. electric field and magnetic field oscillations are perpendicular to each other. They keep on generating each other. The direction of propagation of an EM wave is given by the Poynting Vector which is a vector in a direction perpendicular to both the directions of vibration of electric field as well as magnetic field. Now when light goes from one medium to another, say, from air to glass, what happens is that the E- field polarizes the atoms of glass. Now as the E field is oscillating the polarizing effect is also oscilating , that is , it changes direction of induced dipole moments. so The positive and negative charges inside the glass atoms now also oscillate and generate their own electric and magnetic field. so the net electric and magnetic field at any instant will be the resultant of the fields produced by the original source as well as the fields produced by the charges inside atoms of glass.Hence as the directions of E- field and B- field change ,the corresponding poynting vector also changes. Hence the direction of light is changed.
4. This is a magnification range. It has an objective of focal length 50 cm and an eye piece of focal length 5 cm. That meanwhen we observed any objects under the microscope that shows the 10 times bigger than natural.
5. The compound microscope, often referred to as light microscope, is a type of microscopewhich uses visible light and a system of lenses to magnify images of small samples. Optical microscopes are the oldest design of microscope and were possibly invented in their present compound form in the 17th century. Basic optical microscopes can be very simple, although there are many complex designs which aim to improve resolution and sample contrast.
For the first time multiple lense were used to make it better results. As we know that mainly two lenses are predepr there to magnifinma the objects.
Next is the total magnification that mean the power of magnification is the multiplication of the lower lense power and the upper lense.