chloroplastcontaining

Chloroplast-containing refers to cells, tissues, or organisms that possess chloroplasts, the organelles responsible for photosynthesis in many plant and algal lineages. Chloroplasts capture light energy, drive the light-dependent reactions, and synthesize sugars from carbon dioxide and water using pigments such as chlorophyll.

Chloroplasts have a double membrane envelope, internal thylakoid membranes organized into grana, a surrounding stroma, and their own circular DNA and ribosomes. They are thought to be descendants of cyanobacteria acquired by a eukaryotic host through primary endosymbiosis. Many chloroplast genes have since been transferred to the host nucleus, with the organelles importing most proteins from the cytosol.

Chloroplast-containing organisms include land plants, green and red algae, and many groups of brown algae and other algae that acquired plastids through secondary or tertiary endosymbiosis. In some lineages, chloroplasts are reduced or retained only for essential biosynthetic functions, while photosynthesis can be facultative or absent in others.

Plastid genomes vary in size and gene content among lineages, typically encoding a subset of proteins involved in photosynthesis and gene expression. The presence of chloroplasts makes cells capable of contributing to global carbon fixation and biomass production, influencing ecosystems and agriculture. In addition to photosynthetic chloroplasts, related organelles such as apicoplasts in some parasitic protists illustrate plastid evolution beyond photosynthesis.

Overall, chloroplast-containing cells underpin a large portion of terrestrial and aquatic productivity, forming the basis of many food webs and agricultural systems.