Submitted by admin on Thu, 04/17/2014 - 21:09
definition:
A green pigment, present in all green plants and in cyanobacteria, responsible for the absorption of light to provide energy for photosynthesis. Its molecule contains a magnesium atom held in a porphyrin ring.
sentence:
The green colouring comes from chlorophyll, the same pigment that is found in foliage.
Unlike plants, though, cyanobacteria lack a second kind of chlorophyll, known as chlorophyll b, which in concert with chlorophyll a helps plants capture light.
difficulty:
medium
toefl frequency:
1
toefl classification: