Fucus Algae Structure and Reproduction

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Questions and Answers

What is a characteristic of kingdom Protozoa?

Multicellular organization

Ability to undergo photosynthesis

Phagotrophic feeding behavior (correct)

Presence of cell wall

Which of the following is NOT a characteristic of protozoa?

Motility

Cell wall presence (correct)

Predation

Animal-like behavior

What is a common feature of Chromista?

Heterotrophy

Fungal-like characteristics

Presence of chlorophyll b

Phototrophic nature (correct)

What is unique about the cell wall of diatoms?

It is composed of silica Signup and view all the answers

What is the primary mode of nutrition in diatoms?

Phototrophy Signup and view all the answers

What is a characteristic of diatom colonies?

They have a specific shape Signup and view all the answers

Which of the following is a characteristic of Chromophyte algae?

Presence of chlorophyll c Signup and view all the answers

What is the estimated number of diatom species recognized?

Over 10,000 Signup and view all the answers

What is the main pigment responsible for the golden color of diatoms?

Fucoxanthin Signup and view all the answers

What is the outer wall of a diatom cell called?

Epitheca Signup and view all the answers

What is the arrangement of structure in pennate/bilateral diatoms?

Symmetrical around a central line Signup and view all the answers

What happens to the size of diatom cells after repeated cell division?

The cells decrease in size Signup and view all the answers

What is the purpose of sexual reproduction in diatoms?

To maintain the normal cell size Signup and view all the answers

What is diatomaceous earth used for?

In filtration systems and as a light abrasive Signup and view all the answers

What is the pigment responsible for the dark-brown color of Fucus sp.?

Fucoxanthin Signup and view all the answers

What is the type of branching exhibited by Fucus sp.?

Dichotomous branching Signup and view all the answers

What is the function of the holdfast in Fucus?

To anchor the alga to a surface Signup and view all the answers

What is the characteristic feature of antherozoids in Fucus?

They have unequal flagella Signup and view all the answers

Where are antheridia formed in Fucus?

As lateral branches of paraphyses Signup and view all the answers

What is the number of egg cells produced by each oogonium in Fucus?

8 Signup and view all the answers

Where do fertilization and zygote formation take place in Fucus?

In water Signup and view all the answers

What is the purpose of the wall secreted by the zygote in Fucus?

To prevent the entrance of other antherozoids Signup and view all the answers

Study Notes

Kingdom Protozoa

Eukaryotic organisms that can be unicellular, plasmodial, colonial, or multicellular.
Feed by heterotrophy, meaning they engulf their food.
Examples of protozoa include Amoeba, Paramecium, Euglena, and Trypanosom.
Also includes fungal-like organisms such as myxomycetes and plasmodiophoromycetes.

Kingdom Chromista

Includes diverse organisms that are unicellular or multicellular, filamentous or colonial.
Primarily phototrophic, meaning they produce their own food through photosynthesis.
Contains brown algae, diatoms, oomycetes, and other similar organisms.
Chromista include all chromophyte algae, which have chlorophyll c, not b.

Diatoms

Unicellular, sometimes colonial algae.
Form colonies with particular shapes, such as stars, fans, and ribbons.
Found in almost every aquatic habitat, acting as free-living photosynthetic autotrophs.
Make up the majority of phytoplankton in marine food chains.
Over 10,000 species of diatoms are recognized.

Diatom Structure

Cells are surrounded by a rigid, two-part box-like cell wall composed of silica.
Chloroplasts contain chlorophylls a, c1, and c2, but not chlorophyll b.
Color is due to carotenoids and xanthophylls, particularly fucoxanthin, masking the chlorophyll.
Two-part valves (theca) surround protoplasm with a central nucleus.
Ornamentation can be divided into two basic types: centric/radial and pennate/bilateral.

Diatom Reproduction

Normal asexual method is by cell division, where one cell becomes two.
Daughter cells produce a new hypotheca, and one daughter cell is smaller than the parent cell.
Sexual reproduction occurs when the size of the cell decreases due to repeated cell division.
In sexual reproduction, diploid vegetative cells undergo meiosis to form gametes, which fuse to produce a zygote.

Applications of Diatoms

Diatomaceous earth, a fine, light material, is formed when diatoms die and accumulate on the sea floor.
Diatomaceous earth has various applications, such as in filtration systems and as a light abrasive in products like silver polish or toothpaste.

Fucus sp.

Thallus is dark-brown in color due to the presence of fucoxanthin.
Possesses a midrib and exhibits dichotomous branching.
Thallus is differentiated externally into three parts: a holdfast, stipe, and branched frond.
Reproduces sexually, with antheridia and oogonia formed on the same thallus or different thalli.

Fucus Reproduction

Antheridia arise as lateral branches of paraphyses and produce 64 bilflagellated antherozoids.
Oogonia are stalked and develop directly on the wall of the female conceptacles, producing 8 egg cells.
Fertilization takes place in water, and the zygote immediately secretes a wall to prevent the entrance of other antherozoids.
After about 24 hours, the zygote begins to divide, giving rise to a new individual.

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Description

Learn about the external structure of Fucus algae, including holdfast, stipe, and branched frond, as well as its sexual reproduction process. Understand how antheridia and oogonia are formed and grouped in conceptacles.