The light-gathering apparatus of purple bacteria adapts to varying light intensities by altering its configuration to optimize energy production and prevent damage.
“…’[P]urple bacteria were recently found to adopt different cell designs
depending on light intensity‘…
“Solar energy arrives at the cell in ‘drops’ of light called photons,
which are captured by the light-gathering mechanism of bacteria present
within a special structure called the photosynthetic membrane. Inside
this membrane, light energy is converted into chemical energy to power
all the functions of the cell. The photosynthetic apparatus has two
light harvesting complexes. The first captures the photons and funnels
them to the second, called the reaction center (RC), where the solar
energy is converted to chemical energy. When the light reaches the RCs,
they close for the time it takes the energy to be converted.
“According to the study, purple bacteria adapt to different light
intensities by changing the arrangement of the light harvesting
mechanism, but not in the way one would think by intuition.
“‘One might assume that the more light the cell receives, the more open
reaction centers it has,’ says Johnson. ‘However, that is not always the
case, because with each new generation, purple bacteria create a design
that balances the need to maximize the number of photons trapped and
converted to chemical energy, and the need to protect the cell from an
oversupply of energy that could damage it.’ (Science Daily 2010)
http://www.eurekalert.org/pub_releases/2010-05/uom-pit050310.php
http://arxiv.org/PS_cache/arxiv/pdf/1003/1003.2443v1.pdf
