Lecture 3 Flashcards
Electromagnetic spectrum
Radio waves
Microwaves
Infrared radiation
near- infrared radiation (not in song)
Visible light
ultraviolet
X-rays
Gamma rays
Wavelength of visible light
400-700 nm
Which side of the electromagnetic spectrum is gamma rays on
Right or left
Short or long wavelength
High energy or low energy
Left
Short
High
Which side of the electromagnetic spectrum is radio waves on
Right or left
Short or long wavelength
High energy or low energy
Right
Long
Low
Fluorescence
1- electron absorbs a photon and gets excited to a higher energy state (ie. valence)
2- excited electron returns to its ground state, releasing a photo of longer wavelength (ie. lower energy)
Ex. Start at 600nm and finish at 700nm
Common sources of fluorescence in biology
-intrinsic fluorescence (auto fluorescence) from specimen (ie. pigments)
- fluorescent dyes
- fluorescent proteins
Advantage of fluorescent microscopy
-Allows visualization of specific structures of interest
-Can be used with living specimens (same as regular light microscopy)
Confocal fluorescence microscopes
- INCREASES CONTRAST by capturing very thing slices of specimen
Does this by passing the emitted light through a tiny pinhole, which removes out of focus light
Concepts of electron microscope
- higher resolution than light microscopy since electrons have very short wavelengths compared to visible light
- no “colours” since it’s not light
- requires specimen to be fixed (dead)
- specimens are stained with heavy metals, which electrons can’t pass through
Transmission electron microscopy
TEM
- very thing sections are made using a microtome (fancy meat slicer basically)
-images appear as black object on white background
- light regions are where electrons passed through the sample and hit the camera
- dark regions are where electrons didn’t hit the camera
Scanning Electron Microscopy
SEM
- no sectioning needed just coat the sample with a heavy metal (usually gold)
- the 3D contours of the surface are visualized by scanning an electron beam across the specimen
- typically used at much lower magnifications than TEM
Prokaryotes examples
-Bacteria
-archaea
Eukaryotes examples
Animals
Plants
Fungi
Protists
How big is the average prokaryote
1-3 micrometers
Prokaryotes
-unicellular
-small
-no membrane bound organelles
-DNA found in nucleotid
- single circular chromosome and often several circular plasmids
Eukaryotes
-uni or multicellular
-small to very large
-membrane bound organelles
-DNA housed in nucleus
- one or more linear chromosomes
- Linear DNA
Elements common to all living cells
1- genetic information paradigm (DNA->RNA->protein)
2- plasma membrane
3- cytoplasm
4- ribosomes
5- cytoskeleton
Genetic information paradigm
DNA TO RNA TO PROTEIN
Transcription
DNA to RNA using RNA polymerase
DNA full name
Deoxyribonucleic acid
RNA FULL NAME
Ribonucleic acid
Translation
RNA to protein using ribosomes
