Chloroplast

A chloroplast is a type of <a href="/facts/Membrane-bound_organelle/vhDFnGbs">organelle</a> known as a <a href="/facts/Plastid/INesmXK7">plastid</a> that conducts <a href="/facts/Photosynthesis/TMV7w693">photosynthesis</a> mostly in <a href="/facts/Plant_cell/T4RqyI2f">plant</a> and <a href="/facts/Algae/U1ftVKU3">algal cells</a>. Chloroplasts have a high concentration of <a href="/facts/Chlorophyll/1Sb0NyyM">chlorophyll</a> pigments which capture the <a href="/facts/Radiant_energy/8QHpm6KY">energy from sunlight</a> and convert it to <a href="/facts/Chemical_energy/Y3VP3Ifq">chemical energy</a> and release <a href="/facts/Oxygen/acyn6o8r">oxygen</a>. The chemical energy created is then used to make sugar and other organic molecules from carbon dioxide in a process called the <a href="/facts/Calvin_cycle/M1bIgQb9">Calvin cycle</a>. Chloroplasts carry out a number of other functions, including <a href="/facts/Fatty_acid_synthesis/Cl17j9xE">fatty acid synthesis</a>, <a href="/facts/Amino_acid/WDxYwBny">amino acid</a> synthesis, and the <a href="/facts/Immune_response/dtLulqIy">immune response</a> in plants. The number of chloroplasts per cell varies from one, in some unicellular algae, up to 100 in plants like <a href="/facts/Arabidopsis/SCz1CG26">Arabidopsis</a> and <a href="/facts/Wheat/lrk6HdV3">wheat</a>.
Chloroplasts are highly dynamic—they circulate and are moved around within cells. Their behavior is strongly influenced by environmental factors like light color and intensity. Chloroplasts cannot be made anew by the plant cell and must be inherited by each daughter cell during cell division, which is thought to be inherited from their ancestor—a photosynthetic <a href="/facts/Cyanobacterium/S8bKxIU9">cyanobacterium</a> that was <a href="/facts/Symbiogenesis/2gHlgj4j">engulfed</a> by an early <a href="/facts/Eukaryotic/SkwyPLMA">eukaryotic</a> cell. 
Chloroplasts evolved from an ancient cyanobacterium that was engulfed by an early eukaryotic cell. Because of their endosymbiotic origins, chloroplasts, like <a href="/facts/Mitochondria/ErHqrdJ1">mitochondria</a>, contain their own <a href="/facts/DNA/nB89Iauz">DNA</a> separate from the <a href="/facts/Cell_nucleus/D7sFRa3c">cell nucleus</a>. With one exception (the <a href="/facts/Amoeboid/zhRv2axS">amoeboid</a> <a href="/facts/Paulinella/WU3J0qYj">Paulinella</a> chromatophora), all chloroplasts can be traced back to a single <a href="/facts/Endosymbiotic_event/eWvSS8ID">endosymbiotic event</a>. Despite this, chloroplasts can be found in extremely diverse organisms that are not directly related to each other—a consequence of many <a href="/facts/Secondary_endosymbiotic_events/2gHlgj4j">secondary</a> and even <a href="/facts/Tertiary_endosymbiotic_events/eWvSS8ID">tertiary endosymbiotic events</a>.

Chloroplast open-in-new

Chloroplast