Question

Mature ovum in human being is surrounded by

• A. Plasma membrane
• B. Corona radiata
• C. Zona pellucida
• D. All of these

Answer 1

Answer: (B), (C)

The correct options are
B

Corona radiata

C

Zona pellucida

The zona pellucida (or egg wall) is an outer membrane of the egg. This structure helps the sperm to enter the egg through its hard outer layers. The corona radiata surrounds an egg and consists of two or three layers of cells from the follicle. They are attached to the zona pellucida – the outer protective layer of the egg – and their main purpose is to supply vital proteins to the cell.