Cell Microscopy Flashcards
What is the source of radiation of a light microscope?
Light
What organelles are visible under a light microscope?
- cell membrane
- cytoplasm
- nucleus
- nucleolus
- chromosomes
- mitochondria
- golgi apparatus
- centriole
- chloroplast
- grana
- vacuole
- tonoplast
- cell wall
- plasmodesmata
What is magnification?
The number of times larger an image is than the actual object.
What is resolution?
The distance between two points in a image, or in other words, how detailed the image is.
What is the source of radiation of an electron microscope?
Electron beam
What organelles are visible under an electron microscope?
- ribosomes
- lysosomes
- endoplasmic reticulum
- nuclear envelope
- nuclear pores
- cristae
- secretory vesicles
- cisternae
- microvilli
- microtubules/cytoskeleton
- centrioles
- thylakoids
- cilia
- flagella
- pili
- capsule
What is a millimetre?
mm, 1/1000, 10^-3
What is a micrometre?
μm, 1/1000 000, 10^-6
What is a nanometre?
nm, 1/000 000 000, 10^-9
What is the formula for magnification?
M = I/A
What is the formula for actual image size?
A = M/I
What is the formula for image size?
I = M x A
What is the formula for resolution?
Resolution = 1/2 x wavelength of light
How are images measured with a light microscope?
Images are measured with an eyepiece graticule, and then calibrated with a stage micrometer
What is an eyepiece graticule?
A clear scale, usually with 100 divisions, placed in the eyepiece of the microscope
What is a stage micrometer?
A clear ruler, usually with 0.1 and 0.01 mm divisions, placed on the microscope stage.
What is the maximum resolution of a light microscope?
200 nm
What is the maximum resolution of an electron microscope?
0.5 nm
What is the maximum magnification of a light microscope?
1500 x
What is the maximum magnification of an electron microscope?
100 000 x
What is the visible light spectrum?
400 nm (violet light) - 700 nm (red light)
What makes electrons a suitable source of radiation for microscopes?
- short wavelength
- easily focused using electromagnets
Energy is inversely proportional to:
Wavelength
What are the features of a transmission electron microscope?
- electron beam passed through specimen
- transmitted electrons seen
- can see inside cells
What are the features of a scanning electron microscope?
- electron beam scans surface of specimen
- reflected electrons seen
- 3D image seen
How are specimens prepared to be seen with an electron microscope?
- stains contain heavy metal atoms
- must be in a vacuum
- black and white images generated
- specimens must be dehydrated
