BioSec 2012: Cheryl
Revision as of 15:21, 7 February 2012 by Dsouza3190 (talk | contribs) (Created page with "=Chapter 1: Light and Life= *Light **source of information and energy **Defined as EM radiation **Wave of photons **Can be absorbed by pigments and then used **Colour = light t…")
Chapter 1: Light and Life
- Light
- source of information and energy
- Defined as EM radiation
- Wave of photons
- Can be absorbed by pigments and then used
- Colour = light that is not absorbed by pigment
- Electrons become excited when absorbed by light which in turn then becomes potential energy (photosynthesis)
- Photoreceptor
- light-sensing system
- made up of pigment molecule bound to protein
- eye = organ of animals to sense light
- Problem:
- most light driven processes can only process a certain part of the EM spectrum
- source of energy…too much can cause deadly effects
- pigment melanin in our skin absorbs UV (high energy and can be damaging)
- Circadian rhythms (body clock) the daily cycle of most living organisms have evolved to adapt to the change in light (night and day…plant use photosynthesis during the day and night break glucose)
- Some animals prefer the dark (nocturnal animals like moths)
- Some animals have ancestors that had functional eyes but are not blind (blind mole rat)
- bioluminescent: organisms that use chemical energy to make their own light to attract a mate, camouflage, attract prey or communicate