Spirogyra sp. Characteristics and Habitat

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Questions and Answers

What are the primary habitats of Spirogyra?

Spirogyra primarily occurs in freshwater bodies such as ditches, ponds, and lakes.

Describe the structure of a Spirogyra filament.

A Spirogyra filament is unbranched and consists of cylindrical cells arranged end to end.

What materials compose the cell wall of Spirogyra?

The cell wall of Spirogyra is two-layered and made up of cellulose and pectin.

Where is the cytoplasm located within a Spirogyra cell?

In a Spirogyra cell, the cytoplasm lies in the periphery, enclosing a central vacuole. Signup and view all the answers

What is the role of pyrenoids found in Spirogyra chloroplasts?

Pyrenoids, located within the ribbon-shaped chloroplasts, are involved in the synthesis and storage of starch. Signup and view all the answers

How does Spirogyra reproduce asexually?

Spirogyra reproduces asexually by dividing its thread at the transverse walls into parts that grow into new threads. Signup and view all the answers

Explain the process of scalariform conjugation in Spirogyra.

In scalariform conjugation, two parallel threads approach to form a mating canal, allowing the transfer of contents between cells. Signup and view all the answers

What distinguishes lateral conjugation from scalariform conjugation in Spirogyra?

Lateral conjugation occurs between adjacent cells in one thread, while scalariform conjugation involves two opposing threads. Signup and view all the answers

What happens to the zygotic nucleus during the development of the female moss thread?

The zygotic nucleus undergoes two divisions, one meiotic, producing four nuclei, three of which decompose. Signup and view all the answers

Describe the reproductive process of male moss threads during mating.

The male moss thread decomposes its chloroplasts and forms a diploid zygotic germ, leading to the development of empty cells. Signup and view all the answers

What pigments are found in the plastids of golden yellow algae?

Golden yellow algae contain carotene, xanthophyll, and brown fucoxanthin. Signup and view all the answers

What is the nature of the cell wall in chrysophyta?

Chrysophyta may lack a cell wall, but if present, it is made of pectin and cellulose, with some having silica. Signup and view all the answers

How does asexual reproduction occur in golden yellow algae?

Asexual reproduction in golden yellow algae is carried out by floating bacteria or static bacteria. Signup and view all the answers

What role does fucoxanthin play in the characteristics of phaeophyta?

Fucoxanthin is the pigment that gives phaeophyta its brown color, obscuring other pigments. Signup and view all the answers

Explain the importance of the thick wall surrounding the zygote in moss.

The thick wall protects the diploid zygotic germ as it develops into a new thread. Signup and view all the answers

What environmental conditions do most types of phaeophyta prefer?

Most types of phaeophyta thrive in saltwater environments, often attached to rocks or floating on the ocean's surface. Signup and view all the answers

Study Notes

Spirogyra sp. (Water Silk or Pond Scum)

Found in freshwater bodies such as ditches, ponds, and lakes, noted for slippery, thread-like filaments.
Multicellular filamentous green algae, enveloped in a mucilaginous sheath.
Filaments are unbranched, comprising cylindrical cells arranged end to end.
Cell walls are two-layered, composed of cellulose and pectin.
Cytoplasm is peripheral, surrounding a central vacuole.
Contains one or more ribbon-shaped, spirally-arranged chloroplasts that have pyrenoids.
A single nucleus is located in the center of the vacuole via cytoplasmic strands.

Reproduction in Spirogyra

Asexual Reproduction: Occurs via vegetative propagation where thread segments grow into new threads through division and elongation.
Sexual Reproduction: Involves conjugation, which can be scalariform or lateral.
- Scalariform Conjugation: Two parallel threads approach, forming a mucous substance. Protuberances grow, leading to the fusion of cells and formation of a mating canal. The male cell's contents transfer to the female, resulting in zygote formation surrounded by a thick wall.
- The fertilized germ develops into a new thread following mitotic and meiotic nuclear divisions.
- Lateral Conjugation: Occurs between adjacent cells in a single thread, similar to scalariform but in the same filament, leading to zygotic spores exchange.

Chrysophyta (Golden Yellow Algae)

Characterized by plastids rich in carotene, xanthophyll, and brown fucoxanthin, giving a color range from yellowish green to golden brown.
Storage substances include oils and a protein-like compound called leucosin; starch is absent.
Typically lacks a cell wall, or if present, it consists of pectin and cellulose. Some species have silica-containing walls (e.g., diatoms) in distinctive geometric shapes.
Asexual reproduction is by floating or static bacteria, while sexual reproduction is rare, occurring via oogamy or with isogametes/heterogametes.

Phaeophyta (Brown Algae)

Predominantly found in saltwater environments, often anchored to rocks or floating in oceanic areas.
Characterized by their brown color from fucoxanthin pigment, which obscures other colors.

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Description

Explore the fascinating features of Spirogyra, a multicellular filamentous green alga often found in freshwater bodies. This quiz covers its habitat, structure, and unique characteristics such as its mucilaginous sheath and distinctive cell wall composition.