More microscopy - 2.3 (1) Flashcards
Module 2, Chapter 2, 2.3, Page 19
What started the science of cell biology?
light microscopy
Does light microscopy have limitations?
yes
In which era was the electron microscope founded?
In the middle of the 20th century
What revolutionised the study of cells?
electron microscopy
What does electron microscopy enable biologists to see?
deep inside structures that were invisible under a light microscope
What can be achieved by easily using the appropriate lenses in light microscopy?
increased magnification
In light microscopy, if an image is blurred, what will not be able to be seen?
no more detail
What is the limiting factor?
resolution
What is electron microscopy?
a beam of electrons with a wavelength of less than 1nm is used to illuminate the specimen
What can be seen in more detail with electron microscopy?
more detail of cell ultrastructure
How can more detail of cell ultrastructure be seen?
because electrons have a much smaller wavelength than light waves
What can electron microscopes produce images with magnifications of up to?
x500 000 and still have clear resolution
What has changed the way we understand cells but still has disadvantages?
electron microscopes
Are electron microscopes very expensive pieces of equipment?
yes
Where can electron microscopes be used?
inside a carefully controlled enviroment in a dedicated space
What can happen to specimens as a disadvantage of electron microscopy?
specimens can be damaged by the electron beam
How can specimens be damaged by the electron beam?
because the preparation process is very complex as there is a problem with artefacts
What are artefacts?
structures that are produced due to the preparation process
How can these artefacts be eliminated?
through the improvement of techniques
What are the two types of electron microscopes?
Transmission electron microscope (TEM) and Scanning electron microscope (SEM)
What occurs in transmission electron microscopy?
a beam of electrons is transmitted through a specimen and focused to produce an image
What occurs in scanning electron microscopy?
a beam of electrons is sent across the surface of a specimen and the reflected electrons are collected.
Which type of electron microscope has a better resolution?
transmission electron microscope (TEM)
What resolving power does a transmission electron microscope have?
0.5nm
What resolving power does a scanning electron microscope have?
3-10nm
Which electron microscope produces a stunning three-dimensional image of surfaces?
scanning electron microscope
What valuable information do scanning electron microscopes give us?
the appearance of different organisms
What is resolving power?
the smallest detail that a microscope can resolve when imaging a specimen
