0
Which of the following would be best observed for a bacterial cell using phase contrast microscopy?
Wiki User
∙ 11y ago
Motility
Wiki User
∙ 11y ago
Add your answer:
Earn +20 pts
How is the appearance of microrganisms observed using phase-contrast microscopy versus brightfield microscopy?
The human eye is only sensitive to amplitude (intensity) and wavelength (color), which are observed in a normal bright field microscope. Small, transparent objects like a cell do not change these parameters much, but due to their different refractive index from the surrounding medium, they slow down the light that passes through them. The light gets diffracted and has a phase change of approx. 1/4th of the wavelength (depends on the object thickness). Phase contrast microscopes have two rings, one that provides a hollow cone of light that illuminates the specimen and a second (so called phase plate) which lets the unaltered light pass through a thinner part and the bent light through a thicker part .This introduces another relative phase shift of 1/4, causing a net phase shift of 1/2 of the wavelength. Now this results in destructive interference, resulting in a dark object on a bright background.
Can we see evolution actually happening. Find examples of natural occurrences in the wild or experimental situations in the laboratory in which we can observe evolution occurring?
Evolution can be observed in the wild, such as the formation of anti-biotic resistant bacterial strains.Additionally Bacterial evolution has been observed in a large experiment, specifically the evolution of E.coli to metabolise citrate, a process that E.coli normally cannot undertake. Read more about it here: http://en.wikipedia.org/wiki/E._coli_long-term_evolution_experimentFor more examples of experimental evolution read here: http://en.wikipedia.org/wiki/Experimental_evolution
Why GFP colonies are observed in the plate with pQE30 and GFP construct?
Go to http://www.tsienlab.ucsd.edu/Images.htm you will find bacterial colonies will and can express functional fluorescent proteins. As for the plasmid pQE30, it looks to fit into the category of expression at this level.
What is T in T4 bacteriophage?
The T stands for "tadpole."B-cells are named after the first location in which they were observed, the Bursa of Fabricius.
Is it possible to add a gene to an organism?
Yes, although it hasn't been observed in nature. Scientists have been able to artificially insert a gene into a bacteria using sticky ends of the plasmids and DNA ligase to hold them together, thereby inserting a gene into the bacterial chromosome.
What type of slide works best with phase-contrast microscopy?
Hanging drop can be observed for longer periods of time without drying out.
Two or more objects or ideas observed by Their similarities?
outline or contrast
Inferenes or of what is observed help scientist modify an experiment or procedure?
contrast
What is two or more objects or ideas observed for their difference is called?
contrast
Two or more object or ideas observed for their differences?
outline or contrast
What is the function methylene blue solution in the preparation of cheek cells slide?
Methylene Blue, in this situation, is being used as a microscopy stain. Microscopy stains are used to allow for particular characteristics of cells to be observed in greater detail or to make them easier to see.
What are the techniques used to study cell structure and function?
Cells are observed under the microscope, using several different techniques. Three of these techniques are cell culture, immunostaining and computational genomics.
What are two or more objects or ideas observed by their similarities called?
The term is "contrast" when items are observed or defined by their differences. The word "compare" is used for observed similarities, or more generally for both similarities and differences.
Which of the following types of eclipses will NEVER be observed?
Annular lunar eclipse
How is the appearance of microrganisms observed using phase-contrast microscopy versus brightfield microscopy?
The human eye is only sensitive to amplitude (intensity) and wavelength (color), which are observed in a normal bright field microscope. Small, transparent objects like a cell do not change these parameters much, but due to their different refractive index from the surrounding medium, they slow down the light that passes through them. The light gets diffracted and has a phase change of approx. 1/4th of the wavelength (depends on the object thickness). Phase contrast microscopes have two rings, one that provides a hollow cone of light that illuminates the specimen and a second (so called phase plate) which lets the unaltered light pass through a thinner part and the bent light through a thicker part .This introduces another relative phase shift of 1/4, causing a net phase shift of 1/2 of the wavelength. Now this results in destructive interference, resulting in a dark object on a bright background.
The molecular and structural similarities observed among these organisms is best explained by which of the following?
natural selection
Which of the following forms of light can be observed with telescopes at sea level?
visible light and radio waves
