chlorophyll a

Meanings

1. 1noununcountablebiology

   The main green pigment in plants, algae and some bacteria, which absorbs sunlight so the organism can make sugar by photosynthesis.

   Grammar: Written with a lowercase a, and used without an article: chlorophyll an absorbs red and blue light.

   Patterns

   • chlorophyll a in something
   • the level of chlorophyll a

   Chlorophyll a captures light energy in the leaves of every green plant.

   Scientists measure chlorophyll a to estimate how much algae is in a lake.

   Without chlorophyll a, photosynthesis in most plants could not begin.

2. 2noununcountabletechnical

   The amount of this pigment found in water, measured as a sign of how much algae and plankton are living there.

   Grammar: Used in environmental science, often with concentration or levels.

   Patterns

   • chlorophyll a concentration
   • chlorophyll a levels

   Satellites track chlorophyll a levels across the ocean surface.

   High chlorophyll a concentrations can signal an algal bloom.

   The lake's chlorophyll a reading doubled in July.

Common combinations

chlorophyll a concentration

The chlorophyll a concentration was highest near the river mouth.

measure chlorophyll a

Students measured chlorophyll an in samples of pond water.

chlorophyll a and b

Leaves contain both chlorophyll an and b.

absorb light

Chlorophyll an absorbs light mainly at the red and blue ends of the spectrum.

chlorophyll a levels

Rising chlorophyll a levels warned the officials of a bloom.

Synonyms and how they differ

chlorophyll

Chlorophyll is the general name for the whole group of green pigments, whereas chlorophyll a names the specific main type.

green pigment

Green pigment is an everyday phrase that could mean any green coloring, not just the one used in photosynthesis.

Word family

chlorophyll noun

the family of green photosynthetic pigments

chlorophyll b noun

a second, helper pigment slightly different in structure

chloroplast noun

the cell part where chlorophyll is found

photosynthesis noun

the process by which green organisms use light to make food

Commonly confused: chlorophyll a or chlorophyll b? chlorophyll a or chlorine?

Practice

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