Chapter 2 : Cell studies

Question 1

Schleiden and Schwann elaborated which theory ?

Answer 1

the cell theory

Question 2

What tells us the the cell theory ?

Answer 2

“Cell is the structural and functional units of all living organism”

Question 3

When was the cell theory elaborated by Schleiden and Schwann ?

Answer 3

1838/19th century

Question 4

When was invented the first microscope ?

Answer 4

17th century

Question 5

Who invented the first microscope ?

Answer 5

robert hook

Question 6

When was the cell discovered ?

Answer 6

17th century (as the microscope just appeared)

Question 7

Who discovered protozoa and bacteria ?

Answer 7

Anton van Leuwenhoek

Question 8

When were protozoa and bacteria discovered ?

Answer 8

17th century

Question 9

When was discovered the nucleus of eukaryotes ?

Answer 9

19th century

Question 10

Who discovered the nucleus ?

Answer 10

Robert Brown

Question 11

When were the chromosome and the mitosis discovered ?

Answer 11

19th century

Question 12

Who discovered the chromosome and the mitosis ?

Answer 12

Flemming

Question 13

When was the germ theory created ?

Answer 13

19th century

Question 14

Who made the germ theory ?

Answer 14

Koch and Pasteur

Question 15

Who did the first ever vaccine and when ?

Answer 15

Pasteur to treat a rabbid child in the 19th century

Question 16

When was the golgi apparatus discovered ?

Answer 16

19th century

Question 17

Who discovered the Golgi apparatus ?

Answer 17

Camillo Golgi

Question 18

What’s the function of the Golgi apparatus ?

Answer 18

it stocks proteins and lipids next to the ER and nucleus

Question 19

When was the fluorescence microscope invented ?

Answer 19

20th century : 1940

Question 20

When was the Electron microscope invented ?

Answer 20

20th century : 1960

Question 21

When was the scanning tunneling microscope invented ?

Answer 21

20th century : 1980

Question 22

When was the confocal laser scanning microscope invented ?

Answer 22

20th century : 1980

Question 23

When were FRAP/FRET/CLAFEM discovered ?

Answer 23

20th century

Question 24

What are FRAP, FRET, and CLAFEM ?

Answer 24

they are fluorophore used in fluorescence microscopy

Question 25

What is the resolving power of electron miscroscopy ?

Answer 25

1 angström (10^-10m) to 100µm

Question 26

What can you observe with an electron microscope ?

Answer 26

atoms, small molecules, lipids, proteins, viruses, bacteria, nucleus, eukaryotes (quite small things)

Question 27

What is the resolving power of a light microscope ?

Answer 27

0,42µm to 1cm

Question 28

What can you look at with a light microscope ?

Answer 28

bacteria, nucleus, eukaryotes, frog eggs ... (quite larger things)

Question 29

What's the general principle of a light microscope ?

Answer 29

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

Question 30

What are the 6 main components of a light microscope, from the bottom to the top following the light trajectory ?

Answer 30

``` 1 - Light source 2 - Condensor lens 3 - Specimen 4 - Objective lens 5 - Reflecting prism 6 - Ocular lens ```

Question 31

What are the three main type of light microscopy ?

Answer 31

- phase contrast microscopy - fluorescence microscopy - confocal laser scanning microscopy

Question 32

What are the two main types of electron microscopy ?

Answer 32

- transmission electron microscopy | - scannin electron microscopy

Question 33

What type of image do you receive when using a phase contrast microscope ?

Answer 33

an image in levels on contrast

Question 34

How do you obtain phase constrast microscopy image ?

Answer 34

it's because of the light that isn't in phase anymore when crossing the sample

Question 35

Do we need to stain our sample when using phase constrast microscope ?

Answer 35

no bc the amplitude of the light that go through the sample don't need to be changed to see something

Question 36

What kind of image do you get when using a fluorescence microscope ?

Answer 36

fluo colors on the image

Question 37

what do you need to put on your sample for putting it under a fluorescent microscope ?

Answer 37

we need to add a fluorophore to our sample

Question 38

what is a fluorophore ?

Answer 38

a fluorescent molecule which after being excited re-emits light at a specific wave-length (=color)

Question 39

Name some well-known fluorophore

Answer 39

DAPI, FITC, Rhodamin, GFP

Question 40

In which color emits the fluorophore DAPI ?

Answer 40

in blue ("D"= deep sea)

Question 41

In which color emits the fluorophoe FITC ?

Answer 41

in green ("F"= feuille)

Question 42

In which color emits the fluorophore Rhodamin ?

Answer 42

in red ("R"=rouge/red)

Question 43

In which color emits the fluorophore GFP ?

Answer 43

In green

Question 44

What does the acronym "GFP" stand for ?

Answer 44

Green Fluo Protein

Question 45

What is GFP ?

Answer 45

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

Question 46

How does fluorescence work ?

Answer 46

fluorescence = emission of an electron when it gets back to a stable phase after being excited

Question 47

Are the absorbed light and the emitted light of a sample the same ?

Answer 47

no, they're different

Question 48

Can we observe with our eye through a fluorecence microscope ?

Answer 48

no, we have to use a detector instead of our eye

Question 49

What is immunofluorescence microscopy ?

Answer 49

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

Question 50

What type of image do you get when using confocal laser scanning microscope ?

Answer 50

fluorescent image, but you can get different plans of your specimen and reconstruct it in 3D

Question 51

What do you have to add to your sample in confocal laser scanning microscopy ?

Answer 51

fluorophore

Question 52

How does confocal laser scanning microscopy works ?

Answer 52

a light laser is send directly to our sample (+fluorophore)

Question 53

Thanks to what we have different plans of our sample in confocal laser scanning microscopy ?

Answer 53

thanks to a DICHROMATIC MIRROR that deflects the light source

Question 54

What component allows the maximum resolution in confocal laser scanning microscopy ?

Answer 54

it's the pinhole

Question 55

In a confocal laser scanning microscope, by which component is the signal of the sample collected ?

Answer 55

by the photomultiplier (=detector)

Question 56

Thanks to which component can we observe different plans of the sample with a confocal laser scanning microscope ?

Answer 56

thanks to the pinhole that let pass light from a specific plan, making optical slices of the sample + 3D reconstruction

Question 57

Which is larger : light or electron microscope ?

Answer 57

the electron microscope is larger

Question 58

What's the main difference btw the light and electron microscope ?

Answer 58

it's the way to excite the sample that changes: light or electron

Question 59

What type of image do you get with an electron microscope ?

Answer 59

black and white images

Question 60

depending of what the images of electron microscopy looks dark/light ?

Answer 60

it depends on the atomic number of the elements: the higher it is, the darker it looks

Question 61

What was the problem leading to the creation of the two types of microscopy ?

Answer 61

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

Question 62

What does the acronym "TEM" stand for ?

Answer 62

Transmission Electron Microscope

Question 63

What is a transmission electron microscope ?

Answer 63

the sample is soak in heavy metals = it enters it, so me can see the inside of the cell

Question 64

What does the acronym "SEM" stands for ?

Answer 64

Scanning Electron Microscope

Question 65

What is a transmission electron microscope ?

Answer 65

we spray heavy metals one the sample, so they stay on the surface and that's what we can observe

Question 66

What are the main 5 steps for a classical preparation technic ?

Answer 66

``` 1 - Fixation 2 - Dehydration 3 - Embedding 4 - Thin slices 5 - Observation ```

Question 67

What are the three other main prepartion technic used in microscopy ?

Answer 67

- negative staining - shadowing - freeze fracture and freeze etching