Biology: Dinoflagellates and Diatoms

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Questions and Answers

What is unique about the cell walls of diatoms?

They are embedded with silica (correct)

They are made up of cellulose

They are permeable

They are made up of chitin

What is the term used to describe the accumulation of diatom cell walls over billions of years?

Silica deposit

Diatomaceous earth (correct)

Diatom shell

Diatom fossil

What is the primary mode of locomotion in protists?

Passive floating (correct)

Cilia

Muscles

Flagella

What is the main characteristic of Mycoplasma?

They are the smallest living cells Signup and view all the answers

What is the characteristic of Dinoflagellates?

They are photosynthetic Signup and view all the answers

What is the type of reproduction exhibited by protists?

Both asexual and sexual reproduction Signup and view all the answers

What is the function of flagella or cilia in protists?

To aid in locomotion Signup and view all the answers

What is the characteristic of the cell body of protists?

It contains a well-defined nucleus and membrane-bound organelles Signup and view all the answers

What is the primary use of Diatomite, a soil formed from the fossilized remains of Diatoms?

Filtration of oils and syrups Signup and view all the answers

What is the main characteristic of Diatoms in the oceans?

They are the primary producers Signup and view all the answers

What is the primary mode of nutrition for protozoans?

Heterotrophs Signup and view all the answers

What is the color of Dinoflagellates depending on the main pigments present in their cells?

Yellow, green, brown, blue or red Signup and view all the answers

What is the effect of toxins released by large numbers of red Dinoflagellates?

They kill other marine animals such as fishes Signup and view all the answers

Which of the following protozoans is an example of a flagellated protozoan?

Trypanosoma Signup and view all the answers

What is the characteristic of the cell wall of Dinoflagellates?

It has stiff cellulose plates on the outer surface Signup and view all the answers

What is the primary function of cilia in ciliated protozoans?

To move the organism and steer food into the gullet Signup and view all the answers

What is the arrangement of flagella in Dinoflagellates?

One flagellum lies longitudinally and the other transversely Signup and view all the answers

Which of the following is NOT a characteristic of amoeboid protozoans?

They have flagella Signup and view all the answers

What is the name of the disease caused by the parasitic protozoan Plasmodium?

Malaria Signup and view all the answers

What is the result of rapid multiplication of red Dinoflagellates?

The sea appears red Signup and view all the answers

What is the name of the example of red Dinoflagellates that undergo rapid multiplication?

Gonyaulax Signup and view all the answers

Which of the following groups of protozoans includes organisms that have an infectious spore-like stage in their life cycle?

Sporozoans Signup and view all the answers

Which of the following is an example of a ciliated protozoan?

Paramoecium Signup and view all the answers

What is the primary habitat for amoeboid protozoans?

Fresh water, sea water, or moist soil Signup and view all the answers

Study Notes

Kingdom Protista

Single-celled eukaryotes, but boundaries are not well defined.
Includes Chrysophytes, Dinoflagellates, Euglenoids, Slime moulds, and Protozoans.
Members are primarily aquatic and form a link with other kingdoms.
Cells contain a well-defined nucleus and membrane-bound organelles.
Some have flagella or cilia.
Reproduce asexually and sexually by cell fusion and zygote formation.

Chrysophytes

Includes diatoms and golden algae (desmids).
Found in fresh water and marine environments.
Microscopic and float passively in water currents (plankton).
Most are photosynthetic.
Diatoms have cell walls with silica, making them indestructible.
Diatomaceous earth is formed from accumulated cell wall deposits over billions of years.

Dinoflagellates

Mostly marine and photosynthetic.
Appear yellow, green, brown, blue, or red depending on main pigments.
Cell wall has stiff cellulose plates on the outer surface.
Most have two flagella; one lies longitudinally and the other transversely.
Rapid multiplication can make the sea appear red (red tides).
Toxins released can kill other marine animals such as fish.

Euglenoids

Majority are freshwater organisms found in stagnant water.
Have a protein-rich layer called pellicle instead of a cell wall.
Have two flagella, a short and a long one.
Photosynthetic in the presence of sunlight, but behave like heterotrophs in the absence of sunlight.
Pigments are identical to those present in higher plants.

Slime Moulds

Saprophytic protists.
Body moves along decaying twigs and leaves, engulfing organic material.
Form an aggregation called plasmodium under suitable conditions.
Plasmodium differentiates and forms fruiting bodies bearing spores at their tips during unfavourable conditions.
Spores are extremely resistant and can survive for many years, even under adverse conditions.

Protozoans

All heterotrophs and live as predators or parasites.
Believed to be primitive relatives of animals.
Four major groups: Amoeboid, Flagellated, Ciliated, and Sporozoans.
Amoeboid protozoans move and capture prey using pseudopodia.
Flagellated protozoans have flagella and may be parasitic.
Ciliated protozoans have cilia and a cavity (gullet) for food intake.
Sporozoans have an infectious spore-like stage in their life cycle.

Kingdom Fungi

Heterotrophic organisms with diverse morphology and habitat.
Seen on moist bread, rotten fruits, and as parasites on plants.
Examples include mushrooms, toadstools, and the malarial parasite Plasmodium.

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Description

This quiz covers the characteristics and features of dinoflagellates and diatoms, including their cell structure, pigments, and role in the ocean ecosystem.