biology

Prochloron

Prochloron is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Prochloron rather than just read about it. In short: Prochloron (from the Greek pro (before) and the Greek chloros (green) ) is a genus of unicellular oxygenic photosynthetic prokaryotes commonly found as an extracellular symbiont on coral reefs, particularly in didemnid ascidians (sea squirts). Part of the phylum cyanobacteria, it was theorized (endosymbiotic theory) that Prochloron is a predecessor of chloroplasts, components found in photosynthetic eukaryotic cells.

Key takeaways

Prochloron belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Prochloron to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Prochloron from memory before moving on to harder problems.

Reference excerpt

Prochloron (from the Greek pro (before) and the Greek chloros (green) ) is a genus of unicellular oxygenic photosynthetic prokaryotes commonly found as an extracellular symbiont on coral reefs, particularly in didemnid ascidians (sea squirts). Part of the phylum cyanobacteria, it was theorized (endosymbiotic theory) that Prochloron is a predecessor of chloroplasts, components found in photosynthetic eukaryotic cells. However, this theory is largely refuted by phylogenetic studies which indicate Prochloron is not on the same line of descent that lead to the chloroplasts of algae and land plants. Prochloron was discovered in 1975 by Ralph A. Lewin of the Scripps Institution of Oceanography. Prochloron is one of three known prochlorophytes – cyanobacteria that contain both chlorophyll a and b bound to light-harvesting proteins. The other prochlorophytes are Prochlorococcus marinus, an open-ocean species, and Prochlorothrix hollandica, a filamentous freshwater species. Surprisingly, unlike most cyanobacteria, Prochloron do not contain the red or blue pigments called phycobilins, seen in many species of cyanobacteria. Repeated unsuccessful attempts to culture Prochloron outside a host make them the only known obligate photosymbionts in the phylum Chordata. Strictly speaking, the name "Prochloron" Lewin 1977 was not validly published under either ICNP or ICNafp. The two codes do each have a valid version of the genus:

Prochloron Lewin 1977 ex Hoffmann and Greuter 1993, valid under ICNafp Prochloron (ex Lewin 1977) Florenzano et al. 1986, valid under ICNP by being published in Int. J. Syst. Bacteriol. Lewin originally placed Prochloron in a new family Prochloraceae, new order Prochlorales and a new algal division Prochlorophyta. In 1986, Florenzano et al. published Prochloraceae and Prochlorales under the bacterial code, within the class Photobacteria. Komarek listed Prochlorococcus with Prochloron in Prochloraceae, and assigned the family to Synechococcales, but opined that the two genera are not closely related. LPSN, citing Strunecky et al. 2023 as source, places Prochloron in Microcystaceae, but this is a mistake because Strunecky et al. 2023 clearly place Prochloron in Prochloraceae.

Species The only taxonomically valid species is P. didemni. Again there is a version in each of the two Codes.

References

Guiry, M.D.; Guiry, G.M. (2008). "Prochloron". AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. Retrieved 2009-02-21. Waterbury, John, et al. Little Things Matter A Lot. Oceanus Magazine. 2004, 43(2). Yellowlees, David; et al. (2008). "Metabolic interactions between algal symbionts and invertebrate hosts". Plant, Cell and Environment. 31 (5): 679–694. doi:10.1111/j.1365-3040.2008.01802.x. hdl:2292/14268. PMID 18315536.

Worked examples

Example 1 — a first encounter with Prochloron

Start with the simplest possible case. Write down what Prochloron claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Prochloron before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Prochloron ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Prochloron

In research: Prochloron appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Prochloron in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Prochloron is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cyanobacteria genera, Cyanobacteria stubs, Synechococcales, so understanding it makes those chapters shorter.
In everyday life: Look for Prochloron outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Prochloron” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Prochloron in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Prochloron means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Prochloron out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Prochloron in simple terms?

Why does Prochloron matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Prochloron?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Prochloron.