Question

In telolecithal egg, the yolk is found
A) All over the egg
B) On one side
C) Both the sides
D) Centre

Answer 1

Hint: Yolk appears to accumulate in one hemisphere of the egg and is more abundant. In the vegetal pole, the yolk concentration is highest.

Complete Answer:
- Reproduction is the biological mechanism through which an individual is responsible for creating their own descendants.
- For the continued survival of the planet, reproduction is a must-do operation for any individual. There are a large number of animals living on earth, as we know, and their way of producing eggs is also distinct.
- The proportion of neutral fats and proteins varies and the yolk is also classified as 'protein yolk' or 'fatty yolk.' The eggs are divided into four groups based on the quantity of yolk and they are oligolecithal eggs, mesolecithal eggs, telolecithal eggs, and centrolecithal eggs.

Now, let us find the solution from the options-
The yolk is contained in the telolecithal egg on one pole of the egg i.e., on one side.
The egg normally contains two opposite poles, one of which is the animal pole and the other is the vegetal pole.
A) In telolecithal egg forms, yolk is found on the vegetal pole whereas the other pole remains free.
B) In centrolecithal eggs, yolk is found in the interior at the centre and a thin coat on the exterior surface forms the cytoplasm.
C) In oligolecithal eggs, the granules of yolk are fine, spread uniformly and the volume of yolk is minimal.
D) The amount of yolk in macrolecithal eggs is so large that it covers almost the whole vegetal pole, and the active cytoplasm and nucleus (germinal vesicles) at the animal pole remain limited to a small cap.

Thus, the correct answer is option (B) On one side.

Note: The purpose of the egg yolk is used to provide energy and to synthesize the products needed for the embryonic body to be formed. In sharks, birds, amphibians, ganoids, elasmobranchs, and ling-fish, telolecithal eggs are found. Examples of mesolecithal eggs are eggs of frogs and fish. Oligolecithal eggs are seen in lower chordates, echinoderms. Centrolecithal eggs are found in arthropods especially in insects.