Question

Tertiary egg membrane is
(a)Vitelline membrane
(b)Zona radiata
(c)Albumen
(d)Corona radiata

Answer 1

Hint: Egg Membranes are protective layers varying in structure and texture that surround the eggs of most animals.

Complete answer:
The tertiary egg membrane is generally the albumen that is secreted by the cells of the oviduct when the ovum moves through the oviduct. There are three types of egg membranes.
-The primary membrane is the vitelline membrane. It is produced by the oocyte itself during the growth period. It is generally a thin transparent layer but sometimes it achieves considerable thickness and is multilayered such as in Ascaris and certain vertebrates. In most vertebrates, the primary membrane is streaked with numerous radial canals and is hence known as the zona radiata (the zona pellucida in mammals).
-The secondary membrane, also known as chorion, is secreted by the auxiliary cells of the ovary by its conversion into the material of the membrane. In various arthropods the chorion is saturated with the chorionin, a substance similar in composition to keratin; the chorionin gives the toughness to the membrane.
-The tertiary membranes are secreted by cells of the female’s genital tract when the ovum moves after fertilization through the oviduct. Tertiary membranes include the gelatinous albumen of the eggs of echinoderms, molluscs, fish, and amphibians. The membrane may also include the tough protein membranes that are present in the horny shells of cephalopods and selachians, the fibrous and calcareous shells of the reptiles and the calcareous shells of bird’s egg.
So the correct answer is ‘Albumen’

Note: Egg membranes protect eggs from physical damage, penetration by pathogens and parasites, and dehydration. In many animals, the sticky membranes also help to attach the egg to the substrate such as leaves, rock, soil, etc. The protein membranes provide the nutrient matter to the developing embryos.