Question

Choose the correct combination of statements about Whiplash and Tinsel flagellum
(A). Whiplash flagellum is directed backward
(B). Tinsel flagellum is directed forward
(C). Whiplash and Tinsel flagellum can not coexist
(D). Whiplash and Tinsel flagellum may coexist

• A. (A), (B) and (D) only.
• B. (A), (C) and (D) only.
• C. (A), (B), (C) and (D).
• D. (B), (C) and (D) only.

Hint:

"Heterokont" means "different flagella."
Oomycete zoospores are heterokont, having a forward tinsel flagellum and a backward whiplash flagellum working together.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Flagella are hair-like organelles used for locomotion by motile eukaryotic cells, including the zoospores of Oomycetes and some lower fungi.
Based on surface morphology, flagella are categorized into whiplash and tinsel types.

Step 2: Detailed Explanation:
Let us analyze the morphology and spatial orientation of both flagellar types:
Statement (A): The whiplash flagellum has a smooth surface and a flexible, thin terminal end.
In motile zoospores, it is typically directed backward, serving as a propeller that pushes the spore forward through water.
Thus, Statement (A) is correct.
Statement (B): The tinsel flagellum is covered with numerous lateral, hair-like structures called mastigonemes.
It is directed forward during movement and pulls the zoospore forward.
Thus, Statement (B) is correct.
Statements (C) and (D): Zoospores of heterokont organisms, such as Oomycetes, are biflagellate.
They possess one forward-directed tinsel flagellum and one backward-directed whiplash flagellum on the same cell.
Therefore, these two types of flagella can coexist, making Statement (D) correct and Statement (C) incorrect.
Combining the true statements yields (A), (B), and (D).

Step 3: Final Answer:
The correct combination is (A), (B) and (D) only.