Question

An unarmored dinoflagellate is
A. Ceratium
B. Noctiluca
C. Gonyaulax
D. Both B and C

Answer 1

Hint: Dinoflagellates are unicellular and they possess two dissimilar flagella which arise from the ventral cell side. They belong to protists and have the largest notiluca.

Complete answer:
Let us find the correct answer from the following:
Option A: Ceratium dinoflagellates are characterized by their armored plates, two flagella, and horns. Therefore, this is an incorrect option.

Option B: Noctiluca is free-living marine-dwelling species and lacks the armor plates. It shows bioluminescence, i.e., emit light. Due to phosphorescence the sea glows at night.
Therefore, this is the correct option.

Option C: Gonyaulax has Armored, ovoid to fusiform cells with chloroplasts and proliferate in large numbers. Therefore, this is an incorrect option.

Option D: Noctiluca is an unarmored dinoflagellate and Gonyaulax is armored dinoflagellate. Therefore, this is an incorrect option.

Thus, the correct option is (B) Noctiluca.

Additional information: One of the characteristic and unique features of dinoflagellates is their ability to produce bioluminescence. Bioluminescence is the property by which an organism can produce light on its own. The dinoflagellates which can produce bioluminescence have an enzyme known as luciferase which are present in the cytoplasmic bodies known as scintillons.

Note: Characteristics of dinoflagellates is,
- They are mostly marine and some are found in freshwater too.
- Their colour varies from red, blue, green, yellow.
- They are eukaryotic unicellular organisms.
- They move like a spinning top with the help of their flagella.
- All membrane bound organelles are found in dinoflagellates.
- They are responsible for causing red tide.