Question

Describe the structure of the human ovum with a neat labelled diagram.

Hint:

Remember: Ovum = Large cell with zona pellucida + corona radiata.

Answer 1

Concept: The human ovum (egg) is the female gamete, specialized for fertilization and early development.
Step 1: General features.

• Large, spherical, non-motile cell
• Haploid (n) in nature
• Rich in cytoplasm containing nutrients

Step 2: Structure of ovum.

• Plasma membrane (Oolemma): Outer boundary of the ovum
• Cytoplasm (Ooplasm): Contains organelles and stored nutrients
• Nucleus: Haploid nucleus containing genetic material
• Zona pellucida: Thick glycoprotein layer surrounding the ovum
• Corona radiata: Outer layer of follicular cells providing protection and nourishment
• Perivitelline space: Space between plasma membrane and zona pellucida
• Polar body: Small cell formed during oogenesis

Step 3: Labelled diagram (schematic).
\[ \begin{array}{c} \text{Corona radiata}
\bigcirc
\text{Zona pellucida}
\bigcirc
\text{Plasma membrane (Oolemma)}
\bigcirc
\text{Cytoplasm (Ooplasm)}
\bigcirc
\text{Nucleus}
\end{array} \]
Step 4: Conclusion.
Thus, the human ovum is a well-organized cell with protective layers and stored nutrients essential for fertilization and development.