Question

Yolk cytoplasm contains
A. Ooplasm
B. Protoplasm
C. Deutoplasm
D. Trophoplasm

Answer 1

Hint: Yolk is the nutrient bearing part of the egg whose major function is the supply of nutrients or food for the developing embryo. There are different amounts of yolk that is present in different eggs and they are classified based on the amount of yolk that is alecithal, microlecithal, mesolecithal and megalecithal.

Complete answer:
Let us have a look at all the options given in the question one by one.
First option ooplasm. The definition of ooplasm is that it is the cytoplasm of the egg. Ooplasm is present in all the eggs unlike yolk which can be absent in some eggs.
The next is protoplasm. Protoplasm is a jelly kind of a substance that has the cytoplasm and the nucleus. All the other organelles bathed in the cytoplasm. It is transparent and thick (viscous) in composition.
Deutoplasm is the part of the egg yolk that actually nourishes the embryo. It contains the food particles required for the nourishment of the embryo.
As we saw, the nutritive substance of the egg cell is the yolk and specifically the deutoplasm. Similarly, for a vegetative cell or a somatic cell, the nourishment is provided by the trophoplasm. It is an undifferentiated protoplasm that has taken up the nutritive function.

So, we can conclude that the correct answer is option C – deutoplasm.

Note:
As mentioned above, some eggs lack the yolk. So, in such organisms, the embryo is nourished directly by the maternal blood. It is usually seen in animals that do not lay the eggs and give birth to young ones (viviparous). The reproductive system is said to be matrotrophic.
The reproductive system in which organisms in which embryos are supplied with nutritive yolk is called lecithotrophic.