chloroplast
Americannoun
noun
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A plastid in the cells of green plants and green algae that contains chlorophylls and carotenoid pigments and creates glucose through photosynthesis. In plants, chloroplasts are usually disk-shaped and can reorient themselves in the cell to vary their exposure to sunlight. Chloroplasts contain the saclike membranes known as thylakoids, which contain the chlorophyll and are arranged in stacklike structures known as grana. Besides conducting photosynthesis, plant chloroplasts store starch and are involved in amino acid synthesis. Like mitochondria, chloroplasts have their own DNA that is different from the DNA in the nucleus, and chloroplasts are therefore believed to have evolved from symbiont bacteria, their DNA being a remnant of their past existence as independent organisms.
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See more at cell photosynthesis
Other Word Forms
Etymology
Origin of chloroplast
First recorded in 1885–90; chloro(phyll) + -plast
Compare meaning
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Explanation
The chloroplast is the place in a plant cell where photosynthesis happens. Your rose bushes have chloroplasts, but you don’t. Chloroplast is the combination of two biological terms, plastid (an organelle in a plant cell), and chloros, which means green. If you’re reading about plant biology, you’ll probably recognize chloros in chlorophyll, which is one of the pigments important to photosynthesis, which takes place in chloroplasts.
Vocabulary lists containing chloroplast
Cell Biology - Middle School
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Life Science: Cell Biology
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Cell Biology - High School
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Previous evolutionary trees of plants built by scientists often used the genome of the chloroplast, the organelle that allows plants to perform photosynthesis.
From New York Times • May 11, 2024
It is easy to tell that a certain chloroplast is located above and to the right of the nucleus.
From Science Daily • Mar. 5, 2024
To do this they needed to visualise the structural architecture of the chloroplast RNA polymerase.
From Science Daily • Mar. 4, 2024
The RNA polymerase complex comprises 21 subunits encoded in the two genomes, nuclear and chloroplast.
From Science Daily • Mar. 4, 2024
The large chloroplast in each half is composed of six longitudinal plates, united at the axis of the cell.
From Elements of Structural and Systematic Botany For High Schools and Elementary College Courses by Campbell, Douglas Houghton
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
