Gene transfer is to transfer a gene from one DNA molecule to another DNA molecule. Gene transfer represents a relatively new possibility for the treatment of rare genetic disorders and common multifactorial diseases by changing the expression of a person's genes. In 1928, Griffith reported that a nonpathogenic pneumoccocus strain could become pathogenic when it was mixed with cells of heat-killed pathogenic pneumoccocus, which suggested that the pathogenic genetic material could be transformed from the heat-killed pathogenic pneumoccocus to the nonpathogenic strain (Griffith, 1928). This is the first report for gene transfer observation. However, the transforming substance was not identified in these experiments.
1. Light Microscope Electron Microscope Cell Components Seen cell walls, vacuoles, cytoplasm, chloroplasts, nucleus and plasma membrane. Cell structure and ultrastructure of organelles such as cell wall, nucleus, nucleolus, vacuoles, mitochondria, rough and smooth endoplasmic reticulum, cell membrane, chloroplast, Golgi apparatus, and ribosomes can be seen. Specimen Preparation Simple procedure required and involves staining Procedure is harsh. Illumination Visible light rays are focused by glass lenses.
During the 1590 's, two Dutch spectacle makers, Zacharias Jansen and his father Hans started experimenting with lenses. They put several lenses in a tube and made a very important discovery. The object near the end of the tube appeared to be greatly enlarged, much larger than any simple magnifying glass could achieve by itself. their first microscopes was more of
A few example of it would be in forensic sciences where spectrophotometry is commonly used for evidence tracing and this process uses infrared radiation and visible lights to ascertain light transmission, absorption and reflective properties of any substances. This process uses a microscopic light source analyzer to investigate any materials that are hard to be analyzed by naked eyes. Besides, spectrophotometry is also applied in molecular biological field where the amount of a compound in a sample is determined by spectrophotometer and measures the amount of light absorbed by the sample at each wavelength. Moreover, the growth of microorganisms like bacteria can be measure by using spectrophotometer that is to measure the turbidity of the bacterial culture. In addition, spectrophotometry is a promising method for the diagnosis of some disease and the pathological states such as melanoma.
Researchers use it to examine microorganisms,cells, medical biopsy samples, metal and the features of various surfaces.One of the advantages of the electron microscope is that it uses high magnification ( 20,000,000x) and resolution which allows the researcher to see to closely lying structures as separate. It also uses electron lenses which have electron beams instead of light producing a very thin beam of electrons,sustained by electromagnetic lenses. One of the disadvantages of an electron microscope is that it only gives black and white images, but can be transferred to colour later to help highlight and locate important features.These microscopes are powerful enough to see viruses. Electron microscopes have helped scientists to discover specific cell features such as that of the mitochondria (a similar size to a virus) has a double membrane and that bacteria and single celled organisms are completely different from other cells. Because of the invention of electron microscope we now know what happens within a cell its structure and function.
The non-photographic sensors have the ability to directly record data in digitized form supporting more rapid data processing. Also, it is easier in usage than photographic sensors. Furthermore, this sensor has the ability to measure electromagnetic radiation in narrow bands simultaneously with the same optical system. Also, they have higher radiometric and spectral resolution than the photographic sensors. One more advantage is that non- photographic sensors are able to “find” the radiation from any objects that exist in the field through a wave length range.
Single eyepieces (ocular) with a compound Light Microscope are called monocular while two eyepieces are a binocular. The other name for compound light is a bright field microscope because it has a light source in its base. The principal uses for bright field is to observe of numerous stained specimens and morphology of microorganism, to observe of motility and to measurement of size. Magnification is utility of making an object looked larger. To calculate the total magnification of specimen is an objective lens magnification multiply the ocular lens
The image produced by the first of the two lenses is remagnified by the second lens. The magnification is thus compounded. The microscope we used in the experiment is light microscope, it is an example of compound microscope. The compound microscope is the most familiar form of optical microscope. A
This microscope mainly functions like a light microscope but instead uses electrons instead of a light source when viewing the slide. This is much more accurate and clear because of the lower wavelength of electrons compared to regular light, the electrons are able to give us a resolution which is around a thousand times better than that of a light microscope. Usually a Tumor that hard to classify or diagnose is required to be sent to TEM. Small 1mm portions of the tumor are immediately prepared for TEM by being fixed in
THE MICOSCOPE The microscope is a revolutionary invention made by Antony van leeuwenhoek , a dutch scientist , in the late 17th century , since then the science of life (as known as biology) has been changed forever. The microscope comes in many shapes and forms , such as the optical microscope , the electron microscope and the ultra microscope….etc. Although , it has many types , they all serve the same purpose which is magnifying objects that has components (or the object itself) that cannot be seen with the naked eye so it’s easier to analyse them and identify the problem (if there was one to begin with) , this is the biological point of view for the uses of the microscope , there are many other uses for it such as industrial , physical