Chlorophyceae (Green Algae): Pigments, Pyrenoids and Examples
Biology · Plant Kingdom · NEET
Chlorophyceae are the green algae. They look grass green because chlorophyll a and b are the main pigments. Their stored food is starch, made inside special protein-and-starch bodies called pyrenoids, and their cell wall has an inner cellulose layer and an outer pectose layer. Memory hook: "Green = a + b + Starch in Pyrenoids." Common examples to remember: Chlamydomonas, Volvox, Ulothrix, Spirogyra, Chara.
A green algal cell showing the definite chloroplast with a pyrenoid (P) storing starch and protein, next to the four NEET must-remember facts: pigments chlorophyll a and b, stored food starch, a two-layer cellulose-plus-pectose wall, and the standard NCERT examples.
Your doubts, answered
Which pigments make Chlorophyceae green?
They have chlorophyll a and chlorophyll b as the dominant pigments. Because these two are in charge, the algae look grass green. This is a common NEET point: green algae = chlorophyll a AND b (both). Brown and red algae have other extra pigments (fucoxanthin, phycoerythrin) that hide the green, but Chlorophyceae do not.
What is a pyrenoid and what does it store?
A pyrenoid is a small storage body found inside the chloroplast of green algae. NCERT says pyrenoids contain protein besides starch. So the reserve food (starch) is built up around these pyrenoids. Remember: pyrenoid = starch + protein. Some green algae also store food as oil droplets.
What is the stored food of Chlorophyceae?
The stored (reserve) food is starch, the same kind of starch as in higher plants. This is a favourite NEET trap. Green algae store STARCH. Brown algae store mannitol or laminarin, and red algae store floridean starch. Do not mix these up.
What is the cell wall of green algae made of?
Green algae usually have a rigid cell wall with two layers: an inner layer of cellulose and an outer layer of pectose. Memory tip: 'Cellulose inside, Pectose outside.' This matters because different algal classes have different wall materials, and NEET asks you to match them.
What are the common examples of Chlorophyceae in NCERT?
NCERT lists Chlamydomonas, Volvox, Ulothrix, Spirogyra and Chara. Learn their body type too: Chlamydomonas is unicellular, Volvox is colonial (a hollow ball of cells), Ulothrix and Spirogyra are filamentous (thread-like), and Chara is more complex and monoecious (both sex organs on one plant).
What shapes can the chloroplast take in green algae?
The chloroplast in Chlorophyceae is definite (fixed in shape and place) and can be discoid, plate-like, reticulate (net-like), cup-shaped, spiral or ribbon-shaped depending on the species. Example: Spirogyra has a spiral (ribbon-like) chloroplast, which is why its name means 'spiral'.
How do Chlorophyceae reproduce?
Three ways. Vegetative reproduction is usually by fragmentation (the body breaks into pieces that grow). Asexual reproduction is by flagellated zoospores made in zoosporangia. Sexual reproduction shows a lot of variation and can be isogamous, anisogamous or oogamous. Many green algae are haplontic and show zygotic meiosis (like Chlamydomonas).
⚠️ The NEET trap ✗ Ulothrix stores mannitol, or green algae store floridean starch. ✓ Green algae (Chlorophyceae) like Ulothrix and Volvox store STARCH. Mannitol/laminarin belong to brown algae; floridean starch belongs to red algae. 🧠 NEET repeats this match-the-column trap. Chlorophyceae = starch, ALWAYS. If you see a green alga paired with mannitol or floridean starch, that pair is wrong.
Real NEET questions
NEET 2016 / 2023
Which of the following is incorrectly matched?
A · Ectocarpus - Fucoxanthin
B · Ulothrix - Mannitol ✓
C · Porphyra - Floridian Starch
D · Volvox - Starch
Solution: Ulothrix is a green alga (Chlorophyceae), and its stored food is STARCH, not mannitol. Mannitol is the reserve food of brown algae (Phaeophyceae), so the pair 'Ulothrix - Mannitol' is wrong and is the answer. The other pairs are correct: Ectocarpus (brown alga) has fucoxanthin, Porphyra (red alga) stores floridean starch, and Volvox (green alga) stores starch.
NEET 2017
An example of colonial alga is
A · Chlorella
B · Volvox ✓
C · Ulothrix
D · Spirogyra
Solution: Volvox is the classic colonial green alga: many biflagellate cells arranged in a hollow ball. Chlorella is unicellular, while Ulothrix and Spirogyra are filamentous (thread-like). NCERT itself cites Volvox as the colonial form and Ulothrix/Spirogyra as filamentous forms of Chlorophyceae.
NEET 2017
Zygotic meiosis is characteristic of
A · Marchantia
B · Fucus
C · Funaria
D · Chlamydomonas ✓
Solution: Zygotic meiosis means the zygote is the only diploid cell and it divides by meiosis right when it germinates. This is the haplontic life cycle seen in many green algae. Chlamydomonas, a green alga, is haplontic and shows zygotic meiosis. Marchantia and Funaria are haplo-diplontic, and Fucus (brown alga) is diplontic with gametic meiosis.
Solved Plant Kingdom NEET PYQs
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Yes. Chlamydomonas is a unicellular member of Chlorophyceae (green algae). It is often used as an example of the haplontic life cycle with zygotic meiosis.
Why are green algae grass green and not another colour?
Because chlorophyll a and b are the dominant pigments and there are no strong extra pigments to mask the green. In brown and red algae, pigments like fucoxanthin or phycoerythrin cover the green colour.
Do all green algae have pyrenoids?
Most members have one or more pyrenoids inside the chloroplast, but NCERT says 'most', not all. Pyrenoids store starch and also contain protein. Some green algae store food as oil droplets instead.
Is Chara a green alga?
Yes. Chara is listed by NCERT as a green alga (Chlorophyceae). It is more advanced in structure and is monoecious, meaning both male and female sex organs are on the same plant.
What is the difference in stored food between the three algal classes?
Green algae (Chlorophyceae) store starch, brown algae (Phaeophyceae) store mannitol or laminarin, and red algae (Rhodophyceae) store floridean starch. This is one of the most tested NEET points.
