Transcript Why Bioluminescence? - Fat Tuesday Productions

What is Bioluminescence?
Eric Prange
MLFSC 680
Bioluminescence
http://www8.nos.noaa.gov/coris_glossary/index.aspx?letter=p
http://www.cartage.org.lb/en/themes/Sciences/Earthscience/Oceanogra
phy/OceanWater/Optics/Optics.htm
• Bioluminescence is the
production of light without
heat through chemical
reactions by living
organisms.
Bioluminescence is often
referred to as “cold light.”
• To better understand the
process, we first have to
understand what light is
and how any kind of light
is produced.
The Electromagnetic Spectrum
• Visible light is just one region of the electromagnetic spectrum,
which ranges from gamma rays to radio waves.
• Light has wave-like and particle like properties.
• All electromagnetic light always travels at 3.0 x 108 m/s or “c” the
speed of light and is directly related to the wavelength (“λ”) and
frequency (“ν”) of that light.
• All EM radiation is also made up of individual pieces called
“photons” which have an energy directly related to the frequency of
the light and planks constant (“h”)
C=λν
E =h ν h = 6.63 x 10-34 J.s
Electrons and Light
• While EM radiation can
behave as a particle
including being affected
by gravity and imparting
momentum on other
objects, it does not have
any mass.
• Electrons, like light have
quantized (discrete)
energy values that they
can exist at.
http://outreach.atnf.csiro.au/education/senior/astrophysics/images/spectra/bo
hrhydrogen.gif
Electrons and Light (Cont.)
• One way that electrons can gain and lose
energy is to absorb and emit photons of light.
• Another way is that electrons can gain and
lose energy is by exchanging energy with the
kinetic energy of the molecule (or heat).
• Think of it this way; a black shirt feels hotter
than a white shirt because its electrons
absorbs more light, which is then converted
into heat.
• You also know that the metal in the picture to
the right is extremely hot because it is glowing.
In this case the electrons are absorbing some
of the energy and going into an “excited state.”
When they return to the “ground state” they
give off light.
http://zipser.nl/uploaded_images/
DSCF1446-745840.JPG
Energy and Chemical Reactions
• All chemical reactions involve a
change in energy from the reactants
to the products.
• In most chemical reactions, the
products are lower in total energy
than the reactants and thus energy
must somehow be released to the
surroundings.
• In virtually all chemical reactions of
this type, this energy is released in
the form of heat. These are called
exothermic reactions.
An example of an “exothermic reaction”
http://static.howstuffworks.com/gif/firebreathing-7.jpg
Light and Chemical Reactions
• Some reactions that go from high
to low energy are able to instead
release the extra energy in the
form of photons (or light).
• This unusual class of reactions is
largely due to the molecular
structure of the intermediates that
the reaction goes through and
must at some point create a
molecule in an excited energy
state.
• Two of the most commonly seen
examples of chemiluminescence
are light sticks and luminol.
http://www.blackhawk.com/images/catalog/NOP_
LIGHTSTICKS.jpg
Luminol
• Luminol is mixed with a base (OH-)
and hydrogen peroxide (which
releases O2) to create a
chemiluminescent reaction which
emits blue light.
• Because iron acts as a catalyst for
this reaction, crime scene
investigators can use it to search
for the presence of blood since
hemoglobin contains iron ions.
• Unfortunately, bleach and copper
ions also act as catalysts which
can lead to false positives for this
test.
The luminol reaction
http://en.wikipedia.org/wiki/Lu
minol#Chemiluminescence
The Luminol Reaction
http://en.wikipedia.org/wiki/Luminol#Chemiluminescence
The product in this reaction is in an excited state and eventually
returns to the ground state by giving off a photon of blue light.
The Light Stick Reaction
http://en.wikipedia.org/wiki/Lightstick
1) The chemical reaction above produces excess energy 2) The
energy is then transferred to a fluorescent dye, which goes into
an excited state. 3) The dye returns to the ground state by
releasing a photon of light. 4) The color released depends on the
chemical structure of the dye molecule.
Fluorescence
• Fluorescence is the process in which a molecule
absorbs a photon of light and then re-emits a photon
of light of lower energy.
• The reason the photon released is lower energy is
because a small portion of the energy was
converted into the kinetic energy of the molecule
(heat).
• With black lights, high energy UV light is absorbed
by fluorescent materials and is re-emitted as lower
energy visible light.
Bio Fluorescence
• A large number of organisms fluoresce.
• One famous example is the Crystal
Jellyfish which can emit blue light
through bioluminescence. The blue
light is then absorbed by “green
fluorescent protein” (GFP) and reemitted as green light.
• Biologists have discovered how to
transfer the GFP gene to other
organisms so that they glow green
when exposed to UV light.
• The GFP molecule can also be
attached to macro bio-molecules in
order to trace them as they move
throughout cells.
Works Cited
•
http://en.wikipedia.org/wiki/Electromagnetic_radiation
•
http://www8.nos.noaa.gov/coris_glossary/index.aspx?letter=p
•
http://www.cartage.org.lb/en/themes/Sciences/Earthscience/Oceanography/
OceanWater/Optics/Optics.htm
•
http://outreach.atnf.csiro.au/education/senior/astrophysics/images/spectra/b
ohrhydrogen.gif
•
http://zipser.nl/uploaded_images/DSCF1446-745840.JPG
•
http://www.blackhawk.com/images/catalog/NOP_LIGHTSTICKS.jpg
•
http://en.wikipedia.org/wiki/Luminol#Chemiluminescence
•
http://en.wikipedia.org/wiki/Lightstick
•
http://jellieszone.com/aequorea.htm
•
http://hvd.enslyon.fr/human_virology_dpt/teams/gs_verel/pr_verel/vectors_verel