Chlorophyta Characteristics and Types

Study Notes

Characteristics of Chlorophyta

Green pigment chlorophyll is present.
Lacks traditional plant structures like stems, leaves, and roots.
Reproduction occurs through both sexual and asexual means.
Autotrophic nutrition achieved via photosynthesis.

Types of Chlorophyta

Includes flagellated unicellular forms, such as Chlamydomonas.
Contains non-motile forms, either free-living or symbiotic, like Chlorella.
Features filamentous forms, exemplified by Spirogyra.
Contains colonial species, such as Volvox.

Phylum of Spirogyra

Classified under the phylum Chlorophyta.

Habitat

Typically located on the surface of stagnant water bodies, such as ponds and ditches.

Structure of Spirogyra

Noted for its long filamentous structure, described as a green filamentous alga.
Comprises cylindrical chains of cells linked end to end.
Each filament is covered by a protective mucilage sheath.
Underneath the mucilage lies a rigid cellulose cell wall, providing shape.
The cell features a thin layer of cytoplasm with strands extending into a central vacuole.
The nucleus is centrally suspended in the cytoplasm.
Chloroplasts are ribbon-like, spiraled, and interspersed within the cytoplasmic strands, containing protein-rich colorless patches called pyrenoids.

Nutrition

Photosynthesis allows Spirogyra to synthesize sugars, primarily glucose.
Excess glucose is converted to starch and stored in the pyrenoids.

Classification as a Non-Plant

Despite photosynthesis capability, Spirogyra lacks organized tissues, structures, and specialization.
Its cells are identical and lack the differentiation seen in true plants, which possess stems, leaves, and roots.

Gaseous Exchange

Occurs through simple diffusion of dissolved oxygen and carbon dioxide across cellular surfaces in aquatic environments.

Reproduction

Spirogyra reproduces sexually and asexually.

Asexual Reproduction

Involves binary fission and fragmentation.
Binary fission occurs when the nucleus and organelles divide, followed by cytoplasmic constriction to form two cells.
Fragmentation occurs when a cell breaks off a filament and grows into a new filament.

Sexual Reproduction (Conjugation)

Activated under unfavorable conditions with two distinct cell strains forming conjugation tubes.
Gametes are formed when the contents of each cell change into rounded protoplasmic masses.
Positive strain gametes move through the conjugate tube to the negative strain cell, where nuclei fuse to create a zygote.
The zygote forms a protective coat, becoming a zygospore that can survive harsh conditions.
Upon favorable conditions, such as after rainfall, the zygospore germinates to produce new Spirogyra cells.

Description

Explore the fascinating world of Chlorophyta with this quiz on Spirogyra. Learn about their characteristics, reproductive methods, and different types such as Chlamydomonas and Chlorella. Test your knowledge and deepen your understanding of these unique algae.