Question

Which of the following eukaryotes are devoid of histone proteins?
A. Golden algae
B. Euglenoids
C. Fire algae
D. Slime mould

Answer 1

Hint: Histones are condensed proteins and present as a structural part of the DNA of eukaryotes. The main function of histone is to compact the DNA and regulate chromatin structure to make an impact on gene regulation.

Complete answer: Golden algae, also known as Chrysophytes, are golden in color due to the presence of yellow and brown carotenoids. They are eukaryotic and histone proteins are present in them.
Euglenoids are unicellular and biflagellate algae. The flagella help in the locomotion.
They have histones in their genetic material.

Fire algae, also known as Dinoflagellates, are the only eukaryotic cell that lacks histone protein in their DNA. The name fire algae are given due to the presence of the pigment luciferin, which catalyzed by the enzyme luciferase that produces light as a result of reaction but heat is produced. Thus, they are known as fire algae or luminescent algae.
Slime moulds are fungus-like protists. They have histone proteins in their genetic material.

Hence, the correct answer is option C. Fire algae

Note: Dinoflagellates are unicellular, motile and flagellated algae.
The cell of this algae can be naked or have a cell wall. If the cell wall is present in it, it is made up of cellulose plates.
Chlorophyll A, C, dinoxanthin, and peridinin is the pigmented cell present in it.
It stores its food product as starch or oil.