The function of the undulating membrane in Trypanosoma is _______.
A. To increase the area of absorption
B. To help in movement in viscous blood
C. To catch the food
D. None of the above.

Hint:Undulating membrane is a sinuous elongation of the cytoplasmic membrane performing robust, wavelike, and alternative movements. It is a row of laterally fused long cilia associated in many ciliates with the oral structures.


Complete answer:
To answer this question, first, we need to know about the Trypanosoma. Trypanosoma is a genus of kinetoplastids, a monophyletic group of unicellular parasitic flagellate protozoa. The most of species are transferred by blood-feeding invertebrates, but their mechanisms are different among the different species. Trypanosomes have undulating membranes that extend laterally down the length of the organism. This structure provides further motility to the parasite.
Now, let us find the solution from the option.
Undulating membranes does not cause an increase in area of absorption.
The function of undulating membranes in Trypanosoma is to help movement of viscous blood. The undulating membrane is a sinus extension of the cytoplasmic membrane helping movements. In Trypanosoma it is like a fin associated with a flagellum to enhance motility of the parasite in a viscous fluid.
It also does not help to catch food or nutrients.

Thus, the correct option is B. i.e.To help in movement in viscous blood.

Note:Undulating membrane is present in the trypanosomes, this membrane is also found in other species like trichomonads, and undulating membrane is a hand-like elongation commonly related with the flagellum. The movement of the parasite in a viscous fluid (like blood) is increased by the presence of an undulating membrane. In some ciliates like Tetrahymena, an undulating membrane is composed of a line of fused cilia and assumed to help in collecting food.