Question

Gametes are non-motile in
A. Blue green algae
B. Red algae
C. Both A and B
D. Green algae

Answer 1

Hint: Gametes are reproductive cells of an organism. They are also referred to as sex cells. Male gametes are often called as sperm cells. The female sex cell usually called as egg. Egg is mostly non-motile and larger. But male gametes are small and sometimes motile and sometimes non-motile. In algae, haploid cells act directly as gametophytes as they produce gametes.

Complete answer
Option A Blue green algae: Blue green algae or Cyanophyceae reproduce through simple division or fragmentation or non-motile spores. Also, they do not reveal any motile phase during the life cycle.
Option A is not correct
Option B Red algae: Naturally red algae or Rhodophyceae have a thick and gelatinous cell wall. They lack flagella. The hormogonia of some species are able to move by gliding along surfaces. But, they are characterized by the absence of motile spores or gametes. So, the gametes are non-motile.
Hence, Option B is not correct
Option C Both A and B: Both green algae and red algae are non-motile as seen in the previous points. That is, both A and B are correct.
So, Option C is correct
Option D Green algae: Green algae or Chlorophyceae reproduce by zoospores, which are motile asexual spores with two identical anterior flagella. So, their gametes are not non-motile.
Option D is not correct

Therefore, Option C is the correct answer.

Note:
Some of the male gametes possess flagella, which is a tail-shaped structure. It helps the cell to propel and move. Some species like brown algae have two heterogeneous flagella. One is a long anterior flagellum and another is a short posterior flagellum. In some species, the male gamete is vigorously motile but non-flagellated. Example is the Araphid diatom Tabularia fasciculata.