Algal Division V: Chrysophyta

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Questions and Answers

What is the characteristic of the pigment system of Chrysophyceae?

Composed of chlorophyll A only

Composed of chlorophyll A and C and large amounts of carotenoids and xanthophylls (correct)

Composed of chlorophyll A and B

Composed of chlorophyll A and D and large amounts of chlorophylls

What is the primary component of the cell wall of Chrysophyceae?

Lignin

Cellulose (correct)

Pectin

Chitin

What is the morphology of Chrysophyceae cell walls in many genera?

Composed of a single layer with a U-shape

Composed of two overlapping parts each having a V-shape

Composed of two overlapping parts each having an H-shape (correct)

Composed of a single layer with a spiral shape

What is the characteristic of motile forms of Chrysophyceae?

Having two unequal flagella Signup and view all the answers

What is the characteristic of simple zoospores of Chrysophyceae?

Provided with two apical unequal flagella, one smooth and the other rough Signup and view all the answers

What is the characteristic of the alga Vaucheria?

A siphonous branched alga that inhabits a variety of freshwater and marine habitats Signup and view all the answers

During cell division in diatoms, what happens to the old wall of each newly formed cell?

It forms the epitheca Signup and view all the answers

What is the result of repeated cell divisions in diatoms?

The cell eventually forms an auxospore Signup and view all the answers

What was the previously held view of auxospore formation?

An asexual method Signup and view all the answers

What happens to the diploid nucleus during conjugation in diatoms?

It divides reductionally Signup and view all the answers

What is the type of sexual reproduction in centric diatoms?

Oogamous Signup and view all the answers

What is the result of fertilization in diatoms?

Formation of a zygote Signup and view all the answers

What is the function of the oogonial female cell in diatoms?

It produces eggs Signup and view all the answers

When does cell division usually take place in diatoms?

During the night Signup and view all the answers

What is the characteristic feature of the coenocytic structure of filaments in Vaucheria?

Septa are absent except those separating reproductive structures Signup and view all the answers

How does Vaucheria reproduce vegetatively?

By fragmentation Signup and view all the answers

What is the structure in which zoospores are formed in Vaucheria?

Zoosporangium Signup and view all the answers

What is the characteristic feature of a compound zoospore in Vaucheria?

It is multi-flagellated Signup and view all the answers

What is the process by which the ovum is fertilized in Vaucheria?

By the penetration of a male gamete through a pore Signup and view all the answers

What is the common feature of members of Bacillariophyceae?

They are all unicellular or colonial forms Signup and view all the answers

What is the structure in which antheridia are formed in Vaucheria?

On a lateral branch Signup and view all the answers

What is the result of fertilization in Vaucheria?

The formation of a new multinucleate filament Signup and view all the answers

What is a characteristic of an auxospore?

It produces cells of the maximum size for that particular species. Signup and view all the answers

What is a primary food source for aquatic animals, including fish and whales?

Diatoms Signup and view all the answers

What is the main pigment system that dominates diatoms?

Carotenes and xanthophylls Signup and view all the answers

In what industrial application are diatoms used?

Manufacture of dynamite Signup and view all the answers

In biology, what is the significance of diatom cell walls?

They are used to test the efficacy of high power microscopes Signup and view all the answers

What are the three main components of the reserve food materials in diatoms?

Chrysolaminarine, oil, and fats Signup and view all the answers

What is a proposed origin of petroleum?

Fossilized diatoms Signup and view all the answers

What is the chemical composition of the cell wall in diatoms?

Silicon and calcium carbonate Signup and view all the answers

What is the number of flagella present in motile gametes of diatoms?

One anterior flagellum Signup and view all the answers

What is a use of diatoms in cosmetics?

As an abrasive in toothpaste and face powder Signup and view all the answers

What is the ploidy of diatoms during their vegetative phase?

Diploid Signup and view all the answers

What is the term for the rigid cell wall of diatoms?

Frustule Signup and view all the answers

What is the term for the area where the two valves of the frustule overlap?

Girdle Signup and view all the answers

What is the classification of diatoms based on their shape and arrangement of valves?

Centrales and Pinnales Signup and view all the answers

Study Notes

Division V: Chrysopyhta

Characterized by a wide range of differentiation in various basic taxonomic features, leading some authors to treat some of its six classes as separate divisions.

Class I: Chrysophyceae

Pigment system composed of chlorophyll A and C, and large amounts of carotenoids and xanthophylls, giving a yellow-green appearance.
Reserve food material is Chrysolaminarine, oil, and fats.
Cell wall is composed mainly of cellulose, with two overlapping H-shaped parts in many genera.
Algae can be unicellular, filamentous, or siphonious, with motile forms having two unequal flagella.
Asexual reproduction occurs through the formation of zoospores (simple or compound), with sexual reproduction being isogamous, anisogamous, or oogamous.

Order: Vaucheriales, Family: Vaucheriaceae, Genus: Vaucheria

Siphonous branched alga that inhabits freshwater, marine, and soil habitats.
Coenocytic structure of filaments, with septa absent except those separating reproductive structures from the main filaments.
Vegetative reproduction occurs through fragmentation, while asexual reproduction occurs through zoospores formed in zoosporangia.
Sexual reproduction involves the production of antheridia and oogonia, with fertilization of the ovum and subsequent formation of a zygote.

Class II: Bacillariophyceae

Unicellular or colonial forms, with a pigment system dominated by carotenes and xanthophylls, giving a golden brown color.
Reserve food material is Chrysolaminarine, oil, and fats.
Cell wall is chemically composed of silicon, with motile gametes having a single anterior flagellum.
Diatoms are diploid in their vegetative phase, with meiosis occurring during gamete formation.
The rigid cell wall, known as frustules, is composed of two overlapping halves (epitheca and hypotheca) with a girdle area.
Some pennate diatoms have a fissure known as a raphe, which extends from a central nodule to polar nodules.
Frustules have markings used in taxonomy.

Habit and Occurrence

Diatoms are abundant in all waters, both fresh and marine, and form an important element of the plankton flora.
They are also found in damp soil, rocky walls, dry cliffs, and bark of trees, with some species occurring in hot springs and as epiphytes.
Many diatoms occur as fossils, forming large deposits known as diatomaceous earth.

Reproduction

Cell division involves an increase in volume of the frustule, followed by nuclear division, protoplast division, and the formation of two new cells with one old and one new half wall.
Auxospore formation occurs through sexual reproduction, involving the conjugation of two cells, reductional division, and the formation of gametes, which then unite to form a zygote.
The zygote elongates into an auxospore, which restores the original size of the diatom.

Economic Importance

As food: Diatoms are abundant in water and form the food chain of aquatic animals.
As industrial or commercial value: Diatoms are used in filters, metal polishes, dynamite, insulation, glass, porcelain, paints, toothpaste, and face powder.
In biology: Diatoms are used to test the efficacy of microscopes, and their cell walls are used to examine the liver oil of fish.

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Description

Learn about the characteristics of Division V: Chrysophyta, including its differentiation in taxonomic features and classes such as Chrysophaceae. Discover the pigment system composition of this algae group.