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Prasinophyte

Prasinophyte is a science 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 Prasinophyte rather than just read about it. In short: The prasinophytes are a group of unicellular green algae. Prasinophytes mainly include marine planktonic species, as well as some freshwater representatives.

Prasinophyte — main illustration
Prasinophyte — illustration

Key takeaways

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

Reference excerpt

The prasinophytes are a group of unicellular green algae. Prasinophytes mainly include marine planktonic species, as well as some freshwater representatives. The prasinophytes are morphologically diverse, including flagellates with one to eight flagella and non-motile (coccoid) unicells, as well as dormant or cyst stage phycoma. The cells of many species are covered with organic body scales; others are naked. Well studied genera include Ostreococcus, considered to be the smallest (ca. 0.95 μm) free-living eukaryote, and Micromonas, both of which are found in marine waters worldwide. Prasinophytes have simple cellular structures, containing a single chloroplast and a single mitochondrion. The genomes are relatively small compared to other eukaryotes (about 12 Mbp for Ostreococcus and 21 Mbp for Micromonas). At least one species, the Antarctic form Pyramimonas gelidicola, is capable of phagocytosis and is therefore a mixotrophic algae. Some authors treat the prasinophytes as a polyphyletic grouping of green algae from different clades. As the Tetraphytina emerged in the Prasinophytes, recently authors include it, rendering it monophyletic, and equivalent to chlorophyta.

Morphology

Ecology A study of photosynthetic gene-sequence diversity (rbcL) in the Gulf of Mexico indicated that Prasinophytes are particularly prevalent at the Subsurface Chlorophyll Maximum (SCM) and several different ecotypes of Ostreococcus have been detected in the environment. These ecotypes were thought to be distinguished in the environment by their adaptation to light intensities. O. lucimarinus was isolated from a high-light environment and observed year-round in the coastal North Pacific Ocean. RCC141 was considered low-light, because it was isolated from the lower euphotic zone. These strains, or ecotypes, were later shown to live in different habitats (open-ocean or mesotrophic) and their distributions do not appear to be connected to light availability. O. tauri was isolated from a coastal lagoon and appears to be light-polyvalent. Genetic data indicates that distinct molecular differences exist between the different ecotypes that have been detected. Prasinophytes are subject to infection by large double-stranded DNA viruses belonging to the genus Prasinovirus in the family Phycodnaviridae, as well as a Reovirus. It has been estimated that from 2 to 10% of the Micromonas pusilla population is lysed per day by viruses.

Phylogeny Recent studies agree that the prasinophytes are not a natural group, being highly paraphyletic. Relationships among the groups making up the Chlorophyta are not fully resolved. The cladogram produced by Leliaert et al. 2011 and some modification according to Silar 2016, Leliaert 2016 and Lopes dos Santos et al. 2017 is shown below. The blue shaded groups are or have traditionally been placed in the Prasinophyceae). The species Mesostigma viride has been shown to be a member of a basal clade inside Streptophyta. The others are members of the Chlorophyta.

A 2020 study placed the Palmophyllophyceae (prasinophyte clade VI) in a new phylum outside of the Chlorophyta and Streptophyta, the Prasinodermophyta, as shown below. However, a subsequent genomic study recovered Prasinodermophyta as sister to the revised Chlorophyta and questioned the need for the third division or phylum.

See also Smallest organisms

References

External links

Illustrations

Prasinophyte illustration
Prasinophyte: Representation of a PrasinophyteFlagellumFlagellar hairsFlagellar scalesPit, for communication or fluid exchangeContractile vacuole, regulates the quantity of water inside a cellVacuoleBasal bodyRhizoplast, a striated, fibrous rootGolgi apparatus, modifies proteins and sends them out of the cellEndoplasmic reticulum, the transport network for molecules going to specific parts of the cellEndosome, sorts materialNucleolusNucleusEyespot, photoreceptor used to sense light direction and intensityPlastid membranes (2, primary)Pyrenoid, center of carbon fixationStarch granuleCytoplasmic channelThylakoids, site of the light-dependent reactions of photosynthesisGlycoprotein thecaMitochondrion, creates ATP (energy) for the cell (flat cristae)
Representation of a PrasinophyteFlagellumFlagellar hairsFlagellar scalesPit, for communication or fluid exchangeContractile vacuole, regulates the quantity of water inside a cellVacuoleBasal bodyRhizoplast, a striated, fibrous rootGolgi apparatus, modifies proteins and sends them out of the cellEndoplasmic reticulum, the transport network for molecules going to specific parts of the cellEndosome, sorts materialNucleolusNucleusEyespot, photoreceptor used to sense light direction and intensityPlastid membranes (2, primary)Pyrenoid, center of carbon fixationStarch granuleCytoplasmic channelThylakoids, site of the light-dependent reactions of photosynthesisGlycoprotein thecaMitochondrion, creates ATP (energy) for the cell (flat cristae)

Worked examples

Example 1 — a first encounter with Prasinophyte

Start with the simplest possible case. Write down what Prasinophyte claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 Prasinophyte 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 Prasinophyte 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 Prasinophyte

In research
Prasinophyte appears in science 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 Prasinophyte 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
Prasinophyte is common in secondary-school and first-year university syllabi. It links to neighbouring topics Green algae classes, Historically recognized algae taxa, Prasinophyceae, so understanding it makes those chapters shorter.
In everyday life
Look for Prasinophyte 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.
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How to study Prasinophyte in 20 minutes

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

Frequently asked questions

What is Prasinophyte in simple terms?

The prasinophytes are a group of unicellular green algae. Prasinophytes mainly include marine planktonic species, as well as some freshwater representatives.

Why does Prasinophyte matter?

Because it connects several science 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 Prasinophyte?

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 Prasinophyte.

Tags

  • Green algae classes
  • Historically recognized algae taxa
  • Prasinophyceae

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