Topic 1 - Key Concepts Of Biology - Microscopy Flashcards
What is the primary function of microscopes?
To enlarge the image of extremely small structures such as cells
Microscopes enable the observation of structures that cannot be seen with the naked eye.
Who observed the first cells and in what year?
Robert Hooke in 1665
Hooke used a light microscope to observe cork cells.
What are the main components of a light microscope?
Two lenses and illumination from underneath
The design allows for magnification and resolution of small structures.
What is the maximum magnification of a light microscope?
Approximately 2000x
This allows for the viewing of tissues, cells, and large sub-cellular structures.
Define resolving power in microscopy.
The ability to distinguish between two points
A lower resolving power indicates greater detail in the image.
What is the resolving power of a light microscope?
200nm
This resolving power limits the detail that can be observed.
What significant advancement in microscopy occurred in the 1930s?
The development of the electron microscope
This allowed scientists to view deeper inside sub-cellular structures.
What is used to form an image in an electron microscope?
Electrons
Electrons have a much smaller wavelength than light waves, allowing for higher resolution.
What are the two types of electron microscopes?
Scanning electron microscope (SEM) and transmission electron microscope (TEM)
SEM creates 3D images while TEM creates 2D images detailing organelles.
What is the maximum magnification of a transmission electron microscope?
Up to 2,000,000x
This allows for viewing extremely small structures in detail.
What is the resolving power of a transmission electron microscope?
0.2nm
This high resolving power enables the observation of very small cellular components.
What types of structures can be viewed clearly with electron microscopes?
Organelles such as mitochondria, ribosomes, chloroplasts, and plasmids
Electron microscopes are crucial for studying small cellular structures.
What important discoveries have been facilitated by transmission electron microscopes?
Discovery of viruses such as poliovirus, smallpox, and Ebola
This is especially important as viruses are much smaller than bacteria.
True or False: Electron microscopes can examine proteins in greater detail than light microscopes.
True
This capability has led to many important scientific discoveries.
What is the eyepiece in a microscope?
The part of microscope that we look through to view specimens.
What is the function of the barrel in a microscope?
The upper part of the microscope that can be moved up or down to focus the image.
What does the turret do in a microscope?
The part of the microscope that is rotated to change the magnification lens in use.
What is the role of the lens in a microscope?
The lens increases the magnification of the specimen.
What is the stage of a microscope?
The flat surface on which we place the specimen.
List the steps to use a light microscope.
- Place the slide on the stage and look through the eyepiece lens
- Turn the focus wheel to obtain a clear image
- Start with the lowest objective lens magnification
- Increase the magnification of the objective lens and refocus.
True or False: It is important to remember all steps when using a light microscope to gain full marks in a question about microscopy.
True
What is the first step in preparing a slide for microscopy?
Take a thin layer of cells from your sample by either peeling them off or using a cotton bud.
What is the purpose of chemical stains in microscopy?
Used to make some parts of the specimen more visible when you look at them through the microscope.
What should you do after adding cells to the glass slide?
Carefully lower a coverslip onto your slide, taking care to avoid air bubbles.
Fill in the blank: Magnification = measured size / _______
actual size
How do you calculate actual size in microscopy?
Actual size = measured size / magnification.
What is the formula for total magnification in microscopy?
Total magnification = objective lens magnification x eyepiece lens magnification.
