Chapter 2 : Cell studies Flashcards
Schleiden and Schwann elaborated which theory ?
the cell theory
What tells us the the cell theory ?
“Cell is the structural and functional units of all living organism”
When was the cell theory elaborated by Schleiden and Schwann ?
1838/19th century
When was invented the first microscope ?
17th century
Who invented the first microscope ?
robert hook
When was the cell discovered ?
17th century (as the microscope just appeared)
Who discovered protozoa and bacteria ?
Anton van Leuwenhoek
When were protozoa and bacteria discovered ?
17th century
When was discovered the nucleus of eukaryotes ?
19th century
Who discovered the nucleus ?
Robert Brown
When were the chromosome and the mitosis discovered ?
19th century
Who discovered the chromosome and the mitosis ?
Flemming
When was the germ theory created ?
19th century
Who made the germ theory ?
Koch and Pasteur
Who did the first ever vaccine and when ?
Pasteur to treat a rabbid child in the 19th century
When was the golgi apparatus discovered ?
19th century
Who discovered the Golgi apparatus ?
Camillo Golgi
What’s the function of the Golgi apparatus ?
it stocks proteins and lipids next to the ER and nucleus
When was the fluorescence microscope invented ?
20th century : 1940
When was the Electron microscope invented ?
20th century : 1960
When was the scanning tunneling microscope invented ?
20th century : 1980
When was the confocal laser scanning microscope invented ?
20th century : 1980
When were FRAP/FRET/CLAFEM discovered ?
20th century
What are FRAP, FRET, and CLAFEM ?
they are fluorophore used in fluorescence microscopy
What is the resolving power of electron miscroscopy ?
1 angström (10^-10m) to 100µm
What can you observe with an electron microscope ?
atoms, small molecules, lipids, proteins, viruses, bacteria, nucleus, eukaryotes (quite small things)
What is the resolving power of a light microscope ?
0,42µm to 1cm
What can you look at with a light microscope ?
bacteria, nucleus, eukaryotes, frog eggs … (quite larger things)
What’s the general principle of a light microscope ?
observation of thin and colored samples
sample above a light source -> condensor lens -> trhough the specimen -> objective lense -> reflecting prism -> ocular lens -> eye of the observator
What are the 6 main components of a light microscope, from the bottom to the top following the light trajectory ?
1 - Light source 2 - Condensor lens 3 - Specimen 4 - Objective lens 5 - Reflecting prism 6 - Ocular lens
What are the three main type of light microscopy ?
- phase contrast microscopy
- fluorescence microscopy
- confocal laser scanning microscopy
What are the two main types of electron microscopy ?
- transmission electron microscopy
- scannin electron microscopy
What type of image do you receive when using a phase contrast microscope ?
an image in levels on contrast
How do you obtain phase constrast microscopy image ?
it’s because of the light that isn’t in phase anymore when crossing the sample
Do we need to stain our sample when using phase constrast microscope ?
no bc the amplitude of the light that go through the sample don’t need to be changed to see something
What kind of image do you get when using a fluorescence microscope ?
fluo colors on the image
what do you need to put on your sample for putting it under a fluorescent microscope ?
we need to add a fluorophore to our sample
what is a fluorophore ?
a fluorescent molecule which after being excited re-emits light at a specific wave-length (=color)
Name some well-known fluorophore
DAPI, FITC, Rhodamin, GFP
In which color emits the fluorophore DAPI ?
in blue (“D”= deep sea)
In which color emits the fluorophoe FITC ?
in green (“F”= feuille)
In which color emits the fluorophore Rhodamin ?
in red (“R”=rouge/red)
In which color emits the fluorophore GFP ?
In green
What does the acronym “GFP” stand for ?
Green Fluo Protein
What is GFP ?
a gene that codes for a fluorescent protein, that can be added to the genome of an organimsm to observe it under a flurorescent microscope later
How does fluorescence work ?
fluorescence = emission of an electron when it gets back to a stable phase after being excited
Are the absorbed light and the emitted light of a sample the same ?
no, they’re different
Can we observe with our eye through a fluorecence microscope ?
no, we have to use a detector instead of our eye
What is immunofluorescence microscopy ?
technic that uses a fluorophore fixed to an antibody, so when it will fix to it’s special site, the cell will become fluorescent too
=use the reaction of the immune system
What type of image do you get when using confocal laser scanning microscope ?
fluorescent image, but you can get different plans of your specimen and reconstruct it in 3D
What do you have to add to your sample in confocal laser scanning microscopy ?
fluorophore
How does confocal laser scanning microscopy works ?
a light laser is send directly to our sample (+fluorophore)
Thanks to what we have different plans of our sample in confocal laser scanning microscopy ?
thanks to a DICHROMATIC MIRROR that deflects the light source
What component allows the maximum resolution in confocal laser scanning microscopy ?
it’s the pinhole
In a confocal laser scanning microscope, by which component is the signal of the sample collected ?
by the photomultiplier (=detector)
Thanks to which component can we observe different plans of the sample with a confocal laser scanning microscope ?
thanks to the pinhole that let pass light from a specific plan, making optical slices of the sample + 3D reconstruction
Which is larger : light or electron microscope ?
the electron microscope is larger
What’s the main difference btw the light and electron microscope ?
it’s the way to excite the sample that changes: light or electron
What type of image do you get with an electron microscope ?
black and white images
depending of what the images of electron microscopy looks dark/light ?
it depends on the atomic number of the elements: the higher it is, the darker it looks
What was the problem leading to the creation of the two types of microscopy ?
the higher the atomic number’s element is high, the darker it looks, but in living organisms the main atoms found are H, O, N and C which have a quite low atomic number, so we had to use heavy metal to resolve this problem
What does the acronym “TEM” stand for ?
Transmission Electron Microscope
What is a transmission electron microscope ?
the sample is soak in heavy metals = it enters it, so me can see the inside of the cell
What does the acronym “SEM” stands for ?
Scanning Electron Microscope
What is a transmission electron microscope ?
we spray heavy metals one the sample, so they stay on the surface and that’s what we can observe
What are the main 5 steps for a classical preparation technic ?
1 - Fixation 2 - Dehydration 3 - Embedding 4 - Thin slices 5 - Observation
What are the three other main prepartion technic used in microscopy ?
- negative staining
- shadowing
- freeze fracture and freeze etching
