Editing Chlorophyceae (section)

==Description==
Chlorophycean algae are [[eukaryotic]] organisms composed of [[cell (biology)|cell]]s which occur in a variety of forms. Depending on the species, Chlorophyceae can grow unicellular (e.g. ''[[Chlamydomonas]])'', colonial (e.g. ''[[Volvox]]''), coenocytic (e.g. ''[[Characiosiphon]]''), or filamentous (e.g. ''[[Chaetophora (alga)|Chaetophora]]''). In their vegetative state, some members have [[flagella]] while others produce them only in reproductive stages; still others never produce flagella.<ref name=Graham/>

===Chloroplasts===
Chlorophycean algae have [[chloroplast]]s and nearly all members are [[photosynthetic]]. There are a few exceptions, such as ''[[Polytoma]]'', which have plastids that have lost the ability to photosynthesize.<ref>{{cite journal|doi= 10.1186/s12915-022-01263-w|doi-access= free|title= A new lineage of non-photosynthetic green algae with extreme organellar genomes|date= 2022|last1= Pánek|first1= Tomáš|last2= Barcytė|first2= Dovilė|last3= Treitli|first3= Sebastian C.|last4= Záhonová|first4= Kristína|last5= Sokol|first5= Martin|last6= Ševčíková|first6= Tereza|last7= Zadrobílková|first7= Eliška|last8= Jaške|first8= Karin|last9= Yubuki|first9= Naoji|last10= Čepička|first10= Ivan|last11= Eliáš|first11= Marek|journal= BMC Biology|volume= 20|issue= 1|page= 66|pmid= 35296310|pmc= 8928634}}</ref> They are usually green due to the presence of [[chlorophyll]] [[chlorophyll a|''a'']] and [[chlorophyll b|''b'']]; they can also contain the pigment [[Β-Carotene|beta-carotene]]. Chloroplasts are diverse in morphology and include many forms, including, cup-shaped (e.g. ''Chlamydomonas''), or axial, or parietal and reticulate (e.g. ''[[Oedogonium]]'').<ref name=Graham/>

In many species, there may be one or more storage bodies called [[pyrenoid]]s (central proteinaceous body covered with a starch sheath) that are localised around the chloroplast.<ref>{{cite journal|doi=10.1007/s00239-002-2338-9 |title=Differences in pyrenoid morphology are correlated with differences in the rbcL genes of members of the ''Chloromonas'' lineage (Volvocales, Chlorophyceae) |date=2002 |last1=Nozaki |first1=Hisayoshi |last2=Onishi |first2=Keisuke |last3=Morita |first3=Eiko |journal=Journal of Molecular Evolution |volume=55 |issue=4 |pages=414–430 |pmid=12355262 |bibcode=2002JMolE..55..414N }}</ref> Some algae may also store food in the form of oil droplets.<ref name=":1">{{cite journal| vauthors = Melkonian M, Preisig HR |date=1984 |title= An ultrastructural comparison between Spermatozopsis and Dunaliella (Chlorophyceae)  |journal=Plant Systematics and Evolution | volume=146|issue=1–2|pages=31–46|doi=10.1007/BF00984052 |bibcode=1984PSyEv.146...31M }}</ref> The inner cell wall layer is made of cellulose and the outer layer of pectose.

===Ultrastructure===
Cells of Chlorophyceae usually have two or four [[flagella]], but in some cases may have numerous flagella. The flagella emerge from the apex of the cell, and are connected to the nucleus via [[rhizoplast]]s.<ref name=Graham/> The arrangement of flagella may be in one of two configurations, termed CW ("clockwise") or DO ("directly opposed"). In the CW configuration, the [[basal bodies]] are arranged clockwise in the 1–7 o'clock position. In the DO configuration, the basal bodies are arranged in 12–6 o'clock. Taxa with the CW arrangement and DO arrangement correspond to two different [[clade]]s, roughly corresponding to the orders [[Chlamydomonadales]] and [[Sphaeropleales]], respectively.<ref>{{Cite journal|last=Lewis, Louise A. and Richard M. McCourt|date=2004-10-01|title=Green algae and the origin of land plants|url=https://bsapubs.onlinelibrary.wiley.com/doi/10.3732/ajb.91.10.1535|journal=American Journal of Botany|volume=91| issue = 10|pages=1535–1556| doi=10.3732/ajb.91.10.1535 | pmid=21652308 |bibcode=2004AmJB...91.1535L |via=onlinelibrary.wiley.com}}</ref>

A combination of [[ultrastructural]] features are characteristic of the Chlorophyceae. These include: closed [[mitosis]], the [[telophase]] spindle collapsing before [[cytokinesis]], and a system of [[microtubule]]s called a phycoplast running parallel to the plane of cytokinesis.<ref name=Graham/>

{{Gallery|title=Diversity of Chlorophyceae|align=center|
|File:Chlamydomonas globosa - 400x (13263097835).jpg
 |''Chlamydomonas globosa'' 400x
 |alt1=Light micrograph of Chlamydomonas globosa a round green, single cell 
|File:Volvox aureus.jpg
 |''[[Volvox aureus]]''
 |alt2=Light micrograph of Volvox aureus, a spherical colonial green algae with multiple dense inner colonies
|File: Pediastrum duplex phv.jpg
 |''Pediastrum duplex''
 |alt3=Light micrograph of Pediastrum duplex, a star-shaped colonial green alga 
}}