2.1.1- Microscopes Flashcards
Define the term ‘magnification’.
The number of times larger an image appears, compared to the size of the original object.
Define the term ‘organelles’.
Small structures that are within cells- each of which has a specific function.
Define ‘photomicrograph’.
Photograph of an image seen using an optical microscope.
What is ‘resolution’?
The ability to be able to distinguish between two points clearly.
Microscopes produce what kind of magnification?
Linear magnification.
List four reasons as to why optical (aka light) microscopes are still used in schools, colleges and labs.
- relatively cheap
- relatively easy to use
- can be used to study WHOLE AND LIVING SPECIMENS
- portable- can be used in the field and lab
Explain simply how optical microscopes work.
They rely on lenses to focus a beam of light.
What is the maximum magnification of an optical microscope?
X1500
Explain why light microscopes can not magnify any higher than around x1500 effectively.
As their resolution is limited- they cannot magnify any higher whilst also producing clear images.
What is the maximum resolution of optical microscopes?
200 nanometers.
What are the four types of microscopes?
- Optical microscope
- Laser scanning microscope
- Scanning electron microscope
- Transmission electron microscope
Explain why ribosomes cannot be seen using an optical microscope.
They are about 20nm diameter so are smaller than the resolution of the optical microscope (200nm)
What is the formula for calculating the total magnifying power of an optical microscope?
Total magnification= objective lens magnifying power ‘X’ magnifying power of eyepiece lens
Define the term ‘electron micrograph’.
Photograph of an image that is seen using an electron microscope.
How do modern digital microscopes display their image?
On computer screen.